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An 18th-century depiction of early experimentation in the field of
The scientific method is a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous
knowledge. To be termed scientific, a method of inquiry must be based on empirical and measurable evidence subject to specific principles of reasoning. The Oxford English Dictionary defines the scientific method as: "a method or procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of
The chief characteristic which distinguishes the scientific method from other methods of acquiring knowledge is that scientists seek to let reality speak for itself,[discuss] supporting a theory when a theory's
predictions are confirmed and challenging a theory when its predictions prove false. Although procedures vary from one field of inquiry to another, identifiable features distinguish scientific inquiry from other methods of obtaining knowledge. Scientific researchers propose hypotheses as explanations of phenomena, and design experimental studies to test these hypotheses via predictions which can be derived from them. These steps must be repeatable, to guard against mistake or confusion in any
particular experimenter. Theories that encompass wider domains of inquiry may bind many independently derived hypotheses together in a coherent, supportive structure. Theories, in turn, may help form new hypotheses or place groups of hypotheses into context.
Scientific inquiry is generally intended to be as objective as possible in order to reduce biased interpretations of results. Another basic expectation is to document, archive and share all data and methodology so they are available for careful scrutiny by other scientists, giving them the opportunity to verify results by attempting to reproduce them. This practice, called full disclosure, also allows statistical measures of the reliability of these data to be established (when data is sampled or compared to chance).
? ? ? ? ? o o 1.2 Other components o 2.1 Properties of scientific inquiry o 2.2 Beliefs and biases o 3.1 Characterizations ? ? 3.1.2 Definition ? ? o 3.2 Hypothesis development ? o 3.3 Predictions from the hypothesis ? ? o 3.4 Experiments ? o 3.5 Evaluation and improvement ? o o o 4.2 Pragmatic model
o 5.2 Documentation and replication
? 5.2.2 Data sharing
? ? ? ? ? ? ? ? 5.3 Dimensions of practice o 9 See also o 9.1 Problems and issues o 12 Further reading o Overview
See also: History of scientific method and Timeline of the history of scientific method
According to Morris Kline, "Modern science owes its present flourishing state to a new scientific method which was fashioned almost entirely by Galileo Galilei." Dudley Shapere takes a more measured view of Galileo's contribution.
Johannes Kepler (1571–1630). "Kepler shows his keen logical sense in
detailing the whole process by which he finally arrived at the true orbit. This is the greatest piece of Retroductive reasoning ever performed." – C. S. Peirce, c. 1896, on Kepler's reasoning through explanatory hypotheses
For the beginnings of scientific method: Karl Popper writes of Parmenides (fl. 5th Century BCE):
So what was really new in Parmenides was his axiomatic-deductive method, which Leucippus and Democritus turned into a hypothetical-deductive method, and thus made part of scientific methodology.
According to David Lindberg, Aristotle (4th Century BCE) wrote about the scientific method even if he and his followers did not actually follow what he said. Lindberg also notes that Ptolemy (2nd Century AD) and Ibn al-Haytham (11th Century AD) are among the early examples of people who carried out scientific experiments.  Also, John Losee writes that "the Physics and the Metaphysics contain discussions of certain aspects of scientific method", of which, he says "Aristotle viewed scientific
inquiry as a progression from observations to general principles and back to observations."
The Scientific method is the process by which science is carried out. Because science builds on previous knowledge, it consistently improves our understanding of the world. The scientific method also improves itself in the same way, meaning that it gradually becomes more effective at generating new knowledge. For example, the concept of falsification (first proposed in 1934) reduces confirmation bias by formalizing the attempt to disprove hypotheses rather than prove them. The overall process involves making conjectures (hypotheses), deriving predictions from them as logical consequences, and then carrying out experiments based on those predictions to determine whether the original conjecture was correct. There are difficulties in a formulaic statement of method, however. Though the scientific method is often presented as a fixed sequence of steps, they are better considered as general
principles. Not all steps take place in every scientific inquiry (or to the same degree), and not always in the same order. As noted by William Whewell (1794–1866), "invention, sagacity, [and] genius" are required at every step:
Formulation of a question: The question can refer to the explanation of a specific observation, as in "Why is the sky blue?", but can also be open-ended, as in "How can I design a drug to cure this particular disease?" This stage also involves looking up and
evaluating previous evidence from other scientists, including experience. If the answer is already known, a different question that builds on the previous evidence can be posed. When applying the scientific method to scientific research, determining a good question can be very difficult and affects the final outcome of the investigation.
Hypothesis: An hypothesis is a conjecture, based on the knowledge obtained while formulating the question, that may explain the observed behavior of a part of our universe. The hypothesis might be very specific, e.g., Einstein's equivalence principle or Francis Crick's "DNA makes RNA makes protein", or it might be broad, e.g.,
unknown species of life dwell in the unexplored depths of the oceans.
A statistical hypothesis is a conjecture about some population. For example, the population might be people with a particular disease. The conjecture might be that a new drug will cure the disease in some of those people. Terms commonly associated with statistical hypotheses are null hypothesis and alternative hypothesis. A null hypothesis is the conjecture that the statistical hypothesis is false, e.g., that the new drug does nothing and that any cures are due to chance effects. Researchers normally want to show that the null hypothesis is false. The alternative hypothesis is the desired outcome, e.g., that the drug does better than chance. A final point: a scientific hypothesis must be falsifiable, meaning that one can identify a possible outcome of an experiment that conflicts with predictions deduced from the hypothesis; otherwise, it cannot be meaningfully tested.
Prediction: This step involves determining the logical
consequences of the hypothesis. One or more predictions are then selected for further testing. The less likely that the prediction would be correct simply by coincidence, the stronger evidence it would be if the prediction were fulfilled; evidence is also stronger if the answer to the prediction is not already known, due to the effects of hindsight bias (see also postdiction). Ideally, the prediction must also distinguish the hypothesis from likely
alternatives; if two hypotheses make the same prediction, observing the prediction to be correct is not evidence for either one over the other. (These statements about the relative strength of
evidence can be mathematically derived using Bayes' Theorem.) Testing: This is an investigation of whether the real world behaves as predicted by the hypothesis. Scientists (and other people) test hypotheses by conducting experiments. The purpose of an experiment is to determine whether observations of the real world agree with or conflict with the predictions derived from an hypothesis. If they agree, confidence in the hypothesis increases; otherwise, it
decreases. Agreement does not assure that the hypothesis is true; future experiments may reveal problems. Karl Popper advised
scientists to try to falsify hypotheses, i.e., to search for and test those experiments that seem most doubtful. Large numbers of successful confirmations are not convincing if they arise from experiments that avoid risk. Experiments should be designed to minimize possible errors, especially through the use of appropriate scientific controls. For example, tests of medical treatments are commonly run as double-blind tests. Test personnel, who might
unwittingly reveal to test subjects which samples are the desired test drugs and which are placebos, are kept ignorant of which are which. Such hints can bias the responses of the test subjects. Failure of an experiment does not necessarily mean the hypothesis is false. Experiments always depend on several hypotheses, e.g., that the test equipment is working properly, and a failure may be a failure of one of the auxiliary hypotheses. (See the Duhem-Quine thesis.) Experiments can be conducted in a college lab, on a kitchen table, at CERN's Large Hadron Collider, at the bottom of an ocean, on Mars (using one of the working rovers), and so on. Astronomers do experiments, searching for planets around distant stars. Finally, most individual experiments address highly specific topics for reasons of practicality. As a result, evidence about broader topics is usually accumulated gradually.
Analysis: This involves determining what the results of the
experiment show and deciding on the next actions to take. The
predictions of the hypothesis are compared to those of the null hypothesis, to determine which is better able to explain the data. In cases where an experiment is repeated many times, a statistical analysis such as a chi-squared test may be required. If the evidence has falsified the hypothesis, a new hypothesis is required; if the experiment supports the hypothesis but the evidence is not strong enough for high confidence, other predictions from the hypothesis must be tested. Once a hypothesis is strongly supported by evidence, a new question can be asked to provide further insight on the same topic. Evidence from other scientists and experience are frequently incorporated at any stage in the process. Many iterations may be required to gather sufficient evidence to answer a question with confidence, or to build up many answers to highly specific questions in order to answer a single broader question.
This model underlies the scientific revolution. One thousand years ago, Alhazen demonstrated the importance of forming questions and subsequently testing them, an approach which was advocated by Galileo in 1638 with the publication of Two New Sciences. The current method is based on a
hypothetico-deductive model formulated in the 20th century, although it has undergone significant revision since first proposed (for a more formal discussion, see below).
The basic elements of the scientific method are illustrated by the following example from the discovery of the structure of DNA:
? : Previous investigation of DNA had determined its
chemical composition (the four nucleotides), the structure of
each individual nucleotide, and other properties. It had been
identified as the carrier of genetic information by the
Avery–MacLeod–McCarty experiment in 1944, but the
mechanism of how genetic information was stored in DNA was
: and hypothesized that
DNA had a helical structure.
: If DNA had a helical structure, its X-ray
diffraction pattern would be X-shaped. This prediction was
determined using the mathematics of the helix transform, which
had been derived by Cochran, Crick and Vand (and
independently by Stokes).
: crystallized pure DNA and
performed X-ray diffraction to produce photo 51. The results
showed an X-shape.
: When Watson saw the detailed diffraction pattern, he
immediately recognized it as a helix. He and Crick then
produced their model, using this information along with the
previously known information about DNA’s composition and
about molecular interactions such as hydrogen bonds. ? ? ? ? The discovery became the starting point for many further studies involving the genetic material, such as the field of molecular genetics, and it was awarded the Nobel Prize in 1962. Each step of the example is examined in more detail later in the article.
The scientific method also includes other components required even when all the iterations of the steps above have been completed:
Replication: If an experiment cannot be repeated to produce the same results, this implies that the original results were in error. As a result, it is common for a single experiment to be performed multiple times, especially when there are uncontrolled variables or other indications of experimental error. For significant or surprising results, other scientists may also attempt to replicate the results for themselves, especially if those results would be important to their own work.
External review: The process of peer review involves evaluation of the experiment by experts, who give their opinions anonymously to allow them to give unbiased criticism. It does not certify
correctness of the results, only that the experiments themselves were sound (based on the description supplied by the experimenter). If the work passes peer review, which may require new experiments requested by the reviewers, it will be published in a peer-reviewed scientific journal. The specific journal that publishes the results indicates the perceived quality of the work.
Data recording and sharing: Scientists must record all data very precisely in order to reduce their own bias and aid in replication by others, a requirement first promoted by Ludwik Fleck (1896–1961) and others. They must supply this data to other scientists who wish to replicate any results, extending to the sharing of any experimental samples that may be difficult to obtain.
The goal of a scientific inquiry is to obtain knowledge in the form of testable explanations that can predict the results of future experiments. This allows scientists to gain an understanding of reality, and later use that understanding to intervene in its causal mechanisms (such as to cure disease). The better an explanation is at making predictions, the more useful it is, and the more likely it is to be correct. The most successful explanations, which explain and make accurate predictions in a wide range of circumstances, are called scientific theories.
Most experimental results do not result in large changes in human
understanding; improvements in theoretical scientific understanding is usually the result of a gradual synthesis of the results of different experiments, by various researchers, across different domains of
science. Scientific models vary in the extent to which they have been experimentally tested and for how long, and in their acceptance in the
scientific community. In general, explanations become accepted by a scientific community as evidence in favor is presented, and as
presumptions that are inconsistent with the evidence are falsified. Properties of scientific inquiry
Flying gallop falsified; see image below.
Main article: Sallie Gardner at a Gallop
Muybridge's photographs of The Horse in Motion, 1878, were used to answer the question whether all four feet of a galloping horse are ever off the ground at the same time. This demonstrates a use of photography in science.
An animation of Eadweard Muybridge's studies of a horse galloping in which the exact positions of the feet can no longer be clearly seen.
Scientific knowledge is closely tied to empirical findings, and always remains subject to falsification if new experimental observation
incompatible with it is found. That is, no theory can ever be considered completely certain, since new evidence falsifying it might be discovered.
If such evidence is found, a new theory may be proposed, or (more commonly) it is found that minor modifications to the previous theory are sufficient to explain the new evidence. The strength of a theory is related to how long it has persisted without falsification of its core principles. Confirmed theories are also subject to subsumption by more accurate theories. For example, thousands of years of scientific observations of the planets were explained almost perfectly by Newton's laws. However, these laws were then determined to be special cases of a more general theory (relativity), which explained both the (previously unexplained) exceptions to Newton's laws as well as predicting and explaining other observations such as the deflection of light by gravity. Thus independent, unconnected, scientific observations can be connected to each other, unified by principles of increasing explanatory power.
Since every new theory must explain even more than the previous one, any successor theory capable of subsuming it must meet an even higher standard, explaining both the larger, unified body of observations explained by the previous theory and unifying that with even more observations. In other words, as scientific knowledge becomes more accurate with time, it becomes increasingly harder to produce a more successful theory, simply because of the great success of the theories that already exist. For example, the Theory of Evolution explains the diversity of life on Earth, how species adapt to their environments, and many other patterns observed in the natural world; its most recent major modification was unification with genetics to form the modern evolutionary synthesis. In subsequent modifications, it has also subsumed aspects of many other fields such as biochemistry and molecular biology.
Beliefs and biases
Scientific methodology directs that hypotheses be tested in controlled conditions which can be reproduced by others. The scientific community's pursuit of experimental control and reproducibility diminishes the effects of cognitive biases.
For example, pre-existing beliefs can alter the interpretation of results, as in confirmation bias; this is a heuristic that leads a person with a particular belief to see things as reinforcing their belief, even if another observer might disagree (in other words, people tend to observe what they expect to observe).
A historical example is the conjecture that the legs of a galloping horse are splayed at the point when none of the horse's legs touches the ground,
to the point of this image being included in paintings by its supporters. However, the first stop-action pictures of a horse's gallop by Eadweard Muybridge showed this to be false, and that the legs are instead gathered together.
Another important human bias that plays a role is a preference for new, surprising statements (see appeal to novelty), which can result in a search for evidence that the new is true.
In contrast to the requirement for scientific knowledge to correspond to reality, beliefs based on myth or stories can be believed and acted upon irrespective of truth, often taking advantage of the narrative fallacy that when narrative is constructed its elements become easier to
believe. Myths intended to be taken as true must have their elements assumed a priori, while science requires testing and validation a posteriori before ideas are accepted.
Elements of the scientific method
There are different ways of outlining the basic method used for scientific inquiry. The scientific community and philosophers of science generally agree on the following classification of method components. These
methodological elements and organization of procedures tend to be more characteristic of natural sciences than social sciences. Nonetheless, the cycle of formulating hypotheses, testing and analyzing the results, and formulating new hypotheses, will resemble the cycle described below.
Four essential elements of the scientific method are iterations, recursions, interleavings, or orderings of the following:
? (observations, definitions, and
measurements of the subject of inquiry)
? (theoretical, hypothetical explanations of
observations and measurements of the subject)
? ( including  from the hypothesis or theory)
? (tests of all of the above)
Each element of the scientific method is subject to peer review for possible mistakes. These activities do not describe all that scientists do (see below) but apply mostly to experimental sciences (e.g., physics, chemistry, and biology). The elements above are often taught in the educational system as "the scientific method".
The scientific method is not a single recipe: it requires intelligence, imagination, and creativity. In this sense, it is not a mindless set of standards and procedures to follow, but is rather an ongoing cycle, constantly developing more useful, accurate and comprehensive models and methods. For example, when Einstein developed the Special and General Theories of Relativity, he did not in any way refute or discount Newton's Principia. On the contrary, if the astronomically large, the vanishingly small, and the extremely fast are removed from Einstein's theories – all phenomena Newton could not have observed – Newton's equations are what remain. Einstein's theories are expansions and refinements of Newton's theories and, thus, increase our confidence in Newton's work.
A linearized, pragmatic scheme of the four points above is sometimes offered as a guideline for proceeding:
1. Define a question
2. Gather information and resources (observe)
3. Form an explanatory hypothesis
4. Test the hypothesis by performing an experiment and collecting data
in a reproducible manner
5. Analyze the data
6. Interpret the data and draw conclusions that serve as a starting
point for new hypothesis
7. Publish results
8. Retest (frequently done by other scientists)
The iterative cycle inherent in this step-by-step method goes from point 3 to 6 back to 3 again.
While this schema outlines a typical hypothesis/testing method, it should also be noted that a number of philosophers, historians and
sociologists of science (perhaps most notably Paul Feyerabend) claim that such descriptions of scientific method have little relation to the ways science is actually practiced.
The "operational" paradigm combines the concepts of operational definition, instrumentalism, and utility:
The essential elements of scientific method are operations, observations, [not in citation given]models, and a utility function for evaluating models.
– Some action done to the system being investigated ? – What happens when the operation is done to the system ? – A , , , or the phenomenon itself at
a certain moment ?
? Utility Function – A measure of the usefulness of the model to
explain, predict, and control, and of the cost of use of it. One of the elements of any scientific utility function is the refutability of the model. Another is its simplicity, on the Principle of Parsimony more commonly known as Occam's Razor.
The scientific method depends upon increasingly sophisticated
characterizations of the subjects of investigation. (The subjects can also be called unsolved problems or the unknowns.) For example, Benjamin Franklin conjectured, correctly, that St. Elmo's fire was electrical in nature, but it has taken a long series of experiments and theoretical changes to establish this. While seeking the pertinent properties of the subjects, careful thought may also entail some definitions and
observations; the observations often demand careful measurements and/or counting.
The systematic, careful collection of measurements or counts of relevant quantities is often the critical difference between pseudo-sciences, such as alchemy, and science, such as chemistry or biology. Scientific
measurements are usually tabulated, graphed, or mapped, and statistical manipulations, such as correlation and regression, performed on them. The measurements might be made in a controlled setting, such as a laboratory, or made on more or less inaccessible or unmanipulatable objects such as stars or human populations. The measurements often require specialized scientific instruments such as thermometers, spectroscopes, Particle accelerator, or voltmeters, and the progress of a scientific field is usually intimately tied to their invention and improvement.
"I am not accustomed to saying anything with certainty after only one or two observations." – Andreas Vesalius (1546)
Measurements in scientific work are also usually accompanied by estimates of their uncertainty. The uncertainty is often estimated by making
repeated measurements of the desired quantity. Uncertainties may also be calculated by consideration of the uncertainties of the individual
underlying quantities used. Counts of things, such as the number of people in a nation at a particular time, may also have an uncertainty due to data collection limitations. Or counts may represent a sample of desired
quantities, with an uncertainty that depends upon the sampling method used and the number of samples taken.
Measurements demand the use of operational definitions of relevant
quantities. That is, a scientific quantity is described or defined by how it is measured, as opposed to some more vague, inexact or "idealized" definition. For example, electrical current, measured in amperes, may be operationally defined in terms of the mass of silver deposited in a certain time on an electrode in an electrochemical device that is described in some detail. The operational definition of a thing often relies on comparisons with standards: the operational definition of "mass"
ultimately relies on the use of an artifact, such as a particular kilogram of platinum-iridium kept in a laboratory in France.
The scientific definition of a term sometimes differs substantially from its natural language usage. For example, mass and weight overlap in meaning in common discourse, but have distinct meanings in mechanics. Scientific quantities are often characterized by their units of measure which can later be described in terms of conventional physical units when communicating the work.
New theories are sometimes developed after realizing certain terms have not previously been sufficiently clearly defined. For example, Albert Einstein's first paper on relativity begins by defining simultaneity and the means for determining length. These ideas were skipped over by Isaac Newton with, "I do not define time, space, place and motion, as being well known to all." Einstein's paper then demonstrates that they (viz., absolute time and length independent of motion) were approximations. Francis Crick cautions us that when characterizing a subject, however, it can be premature to define something when it remains ill-understood. In Crick's study of consciousness, he actually found it easier to study awareness in the visual system, rather than to study free will, for example. His cautionary example was the gene; the gene was much more poorly understood before Watson and Crick's pioneering discovery of the
structure of DNA; it would have been counterproductive to spend much time on the definition of the gene, before them.
The history of the discovery of the structure of DNA is a classic example of the elements of the scientific method: in 1950 it was known that genetic inheritance had a mathematical description, starting with the studies of Gregor Mendel, and that DNA contained genetic information (Oswald Avery's
transforming principle). But the mechanism of storing genetic
information (i.e., genes) in DNA was unclear. Researchers in Bragg's laboratory at Cambridge University made X-ray diffraction pictures of various molecules, starting with crystals of salt, and proceeding to more complicated substances. Using clues painstakingly assembled over decades, beginning with its chemical composition, it was determined that it should be possible to characterize the physical structure of DNA, and the X-ray images would be the vehicle. ..2. DNA-hypotheses
Another example: precession of Mercury
Precession of the perihelion (exaggerated)
The characterization element can require extended and extensive study, even centuries. It took thousands of years of measurements, from the Chaldean, Indian, Persian, Greek, Arabic and European astronomers, to fully record the motion of planet Earth. Newton was able to include those measurements into consequences of his laws of motion. But the perihelion of the planet Mercury's orbit exhibits a precession that cannot be fully explained by Newton's laws of motion (see diagram to the right), though it took quite some time to realize this. The observed difference for Mercury's precession between Newtonian theory and observation was one of the things that occurred to Einstein as a possible early test of his theory of General Relativity. His relativistic calculations matched observation much more closely than did Newtonian theory (the difference is
approximately 43 arc-seconds per century), .
Main article: Hypothesis formation
An hypothesis is a suggested explanation of a phenomenon, or alternately a reasoned proposal suggesting a possible correlation between or among a set of phenomena.
Normally hypotheses have the form of a mathematical model. Sometimes, but not always, they can also be formulated as existential statements, stating that some particular instance of the phenomenon being studied has some characteristic and causal explanations, which have the general form of universal statements, stating that every instance of the phenomenon has a particular characteristic.
Scientists are free to use whatever resources they have – their own creativity, ideas from other fields, induction, Bayesian inference, and so on – to imagine possible explanations for a phenomenon under study. Charles Sanders Peirce, borrowing a page from Aristotle (Prior Analytics, 2.25) described the incipient stages of inquiry, instigated by the
"irritation of doubt" to venture a plausible guess, as abductive reasoning. The history of science is filled with stories of scientists claiming a "flash of inspiration", or a hunch, which then motivated them to look for evidence to support or refute their idea. Michael Polanyi made such creativity the centerpiece of his discussion of methodology. William Glen observes that
the success of a hypothesis, or its service to science, lies not simply in its perceived "truth", or power to displace, subsume or reduce a predecessor idea, but perhaps more in its ability to
stimulate the research that will illuminate ? bald suppositions and areas of vagueness.
In general scientists tend to look for theories that are "elegant" or "beautiful". In contrast to the usual English use of these terms, they here refer to a theory in accordance with the known facts, which is nevertheless relatively simple and easy to handle. Occam's Razor serves as a rule of thumb for choosing the most desirable amongst a group of equally explanatory hypotheses.
Linus Pauling proposed that DNA might be a triple helix. This hypothesis was also considered by Francis Crick and James D. Watson but discarded. When Watson and Crick learned of Pauling's hypothesis, they understood
from existing data that Pauling was wrong and that Pauling would soon admit his difficulties with that structure. So, the race was on to figure out the correct structure (except that Pauling did not realize at the time that he was in a race – see section on "DNA-predictions" below) Predictions from the hypothesis
Main article: Prediction in science
Any useful hypothesis will enable predictions, by reasoning including deductive reasoning. It might predict the outcome of an experiment in a laboratory setting or the observation of a phenomenon in nature. The prediction can also be statistical and deal only with probabilities. It is essential that the outcome of testing such a prediction be currently unknown. Only in this case does a successful outcome increase the
probability that the hypothesis is true. If the outcome is already known, it is called a consequence and should have already been considered while formulating the hypothesis.
If the predictions are not accessible by observation or experience, the hypothesis is not yet testable and so will remain to that extent
unscientific in a strict sense. A new technology or theory might make the necessary experiments feasible. Thus, much scientifically based
speculation might convince one (or many) that the hypothesis that other intelligent species exist is true. But since there no experiment now known which can test this hypothesis, science itself can have little to say about the possibility. In future, some new technique might lead to an
experimental test and the speculation would then become part of accepted science.
James D. Watson, Francis Crick, and others hypothesized that DNA had a helical structure. This implied that DNA's X-ray diffraction pattern would be 'x shaped'. This prediction followed from the work of Cochran, Crick and Vand (and independently by Stokes). The
Cochran-Crick-Vand-Stokes theorem provided a mathematical explanation for the empirical observation that diffraction from helical structures produces x shaped patterns.
In their first paper, Watson and Crick also noted that the double helix structure they proposed provided a simple mechanism for DNA replication, writing "It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material". ..4. DNA-experiments
Another example: general relativity
Einstein's prediction (1907): Light bends in a gravitational field Einstein's theory of General Relativity makes several specific
predictions about the observable structure of space-time, such as that light bends in a gravitational field, and that the amount of bending depends in a precise way on the strength of that gravitational field. Arthur Eddington's observations made during a 1919 solar eclipse supported General Relativity rather than Newtonian gravitation. Experiments
Main article: Experiment
Once predictions are made, they can be sought by experiments. If the test results contradict the predictions, the hypotheses which entailed them are called into question and become less tenable. Sometimes the
experiments are conducted incorrectly or are not very well designed, when compared to a crucial experiment. If the experimental results confirm the predictions, then the hypotheses are considered more likely to be correct, but might still be wrong and continue to be subject to further testing. The experimental control is a technique for dealing with observational error. This technique uses the contrast between multiple samples (or observations) under differing conditions to see what varies or what remains the same. We vary the conditions for each measurement, to help isolate what has changed. Mill's canons can then help us figure out what the important factor is. Factor analysis is one technique for discovering the important factor in an effect.
Depending on the predictions, the experiments can have different shapes. It could be a classical experiment in a laboratory setting, a double-blind study or an archaeological excavation. Even taking a plane from New York to Paris is an experiment which tests the aerodynamical hypotheses used for constructing the plane.
Scientists assume an attitude of openness and accountability on the part of those conducting an experiment. Detailed record keeping is essential, to aid in recording and reporting on the experimental results, and
supports the effectiveness and integrity of the procedure. They will also assist in reproducing the experimental results, likely by others. Traces of this approach can be seen in the work of Hipparchus (190–120 BCE), when determining a value for the precession of the Earth, while controlled experiments can be seen in the works of Jābir ibn Hayyān (721–815 CE), al-Battani (853–929) and Alhazen (965–1039).
Watson and Crick showed an initial (and incorrect) proposal for the structure of DNA to a team from Kings College – Rosalind Franklin, Maurice Wilkins, and Raymond Gosling. Franklin immediately spotted the flaws which concerned the water content. Later Watson saw Franklin's detailed X-ray diffraction images which showed an X-shape and was able to confirm the structure was helical. This rekindled Watson and Crick's model building and led to the correct structure. ..1. DNA-characterizations Evaluation and improvement
The scientific method is iterative. At any stage it is possible to refine its accuracy and precision, so that some consideration will lead the scientist to repeat an earlier part of the process. Failure to develop an interesting hypothesis may lead a scientist to re-define the subject under consideration. Failure of a hypothesis to produce interesting and testable predictions may lead to reconsideration of the hypothesis or of the definition of the subject. Failure of an experiment to produce
interesting results may lead a scientist to reconsider the experimental method, the hypothesis, or the definition of the subject.
Other scientists may start their own research and enter the process at any stage. They might adopt the characterization and formulate their own hypothesis, or they might adopt the hypothesis and deduce their own
predictions. Often the experiment is not done by the person who made the prediction, and the characterization is based on experiments done by someone else. Published results of experiments can also serve as a hypothesis predicting their own reproducibility.
After considerable fruitless experimentation, being discouraged by their
superior from continuing, and numerous false starts, Watson and
Crick were able to infer the essential structure of DNA by concrete modeling of the physical shapes of the nucleotides which comprise it. They were guided by the bond lengths which had been deduced by Linus Pauling and by Rosalind Franklin's X-ray diffraction images. ..DNA Example
Science is a social enterprise, and scientific work tends to be accepted by the scientific community when it has been confirmed. Crucially,
experimental and theoretical results must be reproduced by others within the scientific community. Researchers have given their lives for this vision; Georg Wilhelm Richmann was killed by ball lightning (1753) when attempting to replicate the 1752 kite-flying experiment of Benjamin Franklin.
To protect against bad science and fraudulent data, government
research-granting agencies such as the National Science Foundation, and science journals, including Nature and Science, have a policy that
researchers must archive their data and methods so that other researchers can test the data and methods and build on the research that has gone before. Scientific data archiving can be done at a number of national archives in the U.S. or in the World Data Center.
Models of scientific inquiry
Main article: Models of scientific inquiry
The classical model of scientific inquiry derives from Aristotle, who distinguished the forms of approximate and exact reasoning, set out the threefold scheme of abductive, deductive, and inductive inference, and also treated the compound forms such as reasoning by analogy.
See also: Pragmatic theory of truth
In 1877, Charles Sanders Peirce (/?p?rs/ like "purse"; 1839–1914) characterized inquiry in general not as the pursuit of truth per se but as the struggle to move from irritating, inhibitory doubts born of surprises, disagreements, and the like, and to reach a secure belief, belief being that on which one is prepared to act. He framed scientific inquiry as part of a broader spectrum and as spurred, like inquiry
generally, by actual doubt, not mere verbal or hyperbolic doubt, which he held to be fruitless. He outlined four methods of settling opinion, ordered from least to most successful:
1. The method of tenacity (policy of sticking to initial belief) –
which brings comforts and decisiveness but leads to trying to ignore contrary information and others' views as if truth were
intrinsically private, not public. It goes against the social
impulse and easily falters since one may well notice when another's opinion is as good as one's own initial opinion. Its successes can shine but tend to be transitory.
2. The method of authority – which overcomes disagreements but
sometimes brutally. Its successes can be majestic and long-lived, but it cannot operate thoroughly enough to suppress doubts
indefinitely, especially when people learn of other societies
present and past.
3. The method of the a priori – which promotes conformity less
brutally but fosters opinions as something like tastes, arising in conversation and comparisons of perspectives in terms of "what is agreeable to reason." Thereby it depends on fashion in paradigms and goes in circles over time. It is more intellectual and
respectable but, like the first two methods, sustains accidental and capricious beliefs, destining some minds to doubt it.
4. The scientific method – the method wherein inquiry regards itself
as fallible and purposely tests itself and criticizes, corrects, and improves itself.
Peirce held that slow, stumbling ratiocination can be dangerously
inferior to instinct and traditional sentiment in practical matters, and that the scientific method is best suited to theoretical research, which in turn should not be trammeled by the other methods and practical ends; reason's "first rule" is that, in order to learn, one must desire to learn and, as a corollary, must not block the way of inquiry. The scientific method excels the others by being deliberately designed to arrive – eventually – at the most secure beliefs, upon which the most successful practices can be based. Starting from the idea that people seek not truth per se but instead to subdue irritating, inhibitory doubt, Peirce showed how, through the struggle, some can come to submit to truth for the sake of belief's integrity, seek as truth the guidance of potential practice correctly to its given goal, and wed themselves to the scientific method.
For Peirce, rational inquiry implies presuppositions about truth and the real; to reason is to presuppose (and at least to hope), as a principle of the reasoner's self-regulation, that the real is discoverable and independent of our vagaries of opinion. In that vein he defined truth as the correspondence of a sign (in particular, a proposition) to its object and, pragmatically, not as actual consensus of some definite, finite community (such that to inquire would be to poll the experts), but instead as that final opinion which all investigators would reach sooner or later but still inevitably, if they were to push investigation far enough, even when they start from different points. In tandem he defined the real as a true sign's object (be that object a possibility or quality, or an actuality or brute fact, or a necessity or norm or law), which is what it is independently of any finite community's opinion and, pragmatically, depends only on the final opinion destined in a sufficient investigation. That is a destination as far, or near, as the truth itself to you or me or the given finite community. Thus his theory of inquiry boils down to "Do the science." Those conceptions of truth and the real involve the idea of a community both without definite limits (and thus potentially
self-correcting as far as needed) and capable of definite increase of knowledge. As inference, "logic is rooted in the social principle" since
it depends on a standpoint that is, in a sense, unlimited.
Paying special attention to the generation of explanations, Peirce outlined the scientific method as a coordination of three kinds of
inference in a purposeful cycle aimed at settling doubts, as follows (in §III–IV in "A Neglected Argument" except as otherwise noted):
1. Abduction (or retroduction). Guessing, inference to explanatory hypotheses for selection of those best worth trying. From abduction, Peirce distinguishes induction as inferring, on the basis of tests, the
proportion of truth in the hypothesis. Every inquiry, whether into ideas, brute facts, or norms and laws, arises from surprising observations in one or more of those realms (and for example at any stage of an inquiry already underway). All explanatory content of theories comes from
abduction, which guesses a new or outside idea so as to account in a simple, economical way for a surprising or complicative phenomenon. Oftenest, even a well-prepared mind guesses wrong. But the modicum of success of our guesses far exceeds that of sheer luck and seems born of attunement to nature by instincts developed or inherent, especially insofar as best guesses are optimally plausible and simple in the sense, said Peirce, of the "facile and natural", as by Galileo's natural light of reason and as distinct from "logical simplicity". Abduction is the most fertile but least secure mode of inference. Its general rationale is inductive: it succeeds often enough and, without it, there is no hope of sufficiently expediting inquiry (often multi-generational) toward new truths.
Coordinative method leads from abducing a plausible hypothesis to judging
it for its testability and for how its trial would economize inquiry
itself. Peirce calls his pragmatism "the logic of abduction". His pragmatic maxim is: "Consider what effects that might conceivably have practical bearings you conceive the objects of your conception to have. Then, your conception of those effects is the whole of your conception of the object". His pragmatism is a method of reducing conceptual confusions fruitfully by equating the meaning of any conception with the conceivable practical implications of its object's conceived effects – a method of experimentational mental reflection hospitable to forming hypotheses and conducive to testing them. It favors efficiency. The hypothesis, being insecure, needs to have practical implications leading at least to mental tests and, in science, lending themselves to scientific tests. A simple but unlikely guess, if uncostly to test for falsity, may belong first in line for testing. A guess is intrinsically worth testing if it has instinctive plausibility or reasoned objective probability, while subjective likelihood, though reasoned, can be misleadingly seductive. Guesses can be chosen for trial strategically, for their caution (for which Peirce gave as example the game of Twenty Questions), breadth, and incomplexity. One can hope to discover only that which time would reveal through a learner's sufficient experience anyway, so the point is to expedite it; the economy of research is what demands the leap, so to speak, of abduction and governs its art.
2. Deduction. Two stages:
i. Explication. Unclearly premissed, but deductive, analysis of the hypothesis in order to render its parts as clear as possible.
ii. Demonstration: Deductive Argumentation, Euclidean in procedure. Explicit deduction of hypothesis's consequences as predictions, for induction to test, about evidence to be found. Corollarial or, if needed, Theorematic.
3. Induction. The long-run validity of the rule of induction is deducible from the principle (presuppositional to reasoning in general) that the real is only the object of the final opinion to which adequate
investigation would lead; anything to which no such process would ever lead would not be real. Induction involving ongoing tests or observations follows a method which, sufficiently persisted in, will diminish its error below any predesignate degree. Three stages:
i. Classification. Unclearly premissed, but inductive, classing of objects of experience under general ideas.
ii. Probation: direct Inductive Argumentation. Crude (the
enumeration of instances) or Gradual (new estimate of proportion of truth in the hypothesis after each test). Gradual Induction is Qualitative or Quantitative; if Qualitative, then dependent on weightings of qualities or characters; if Quantitative, then dependent on measurements, or on statistics, or on countings. iii. Sentential Induction. "...which, by Inductive reasonings, appraises the different Probations singly, then their combinations, then makes self-appraisal of these very appraisals themselves, and passes final judgment on the whole result".
Communication and community
Frequently the scientific method is employed not only by a single person, but also by several people cooperating directly or indirectly. Such cooperation can be regarded as one of the defining elements of a scientific community. Various techniques have been developed to ensure the integrity of scientific methodology within such an environment.
Peer review evaluation
Scientific journals use a process of peer review, in which scientists' manuscripts are submitted by editors of scientific journals to (usually one to three) fellow (usually anonymous) scientists familiar with the field for evaluation. The referees may or may not recommend publication, publication with suggested modifications, or, sometimes, publication in another journal. This serves to keep the scientific literature free of unscientific or pseudoscientific work, to help cut down on obvious errors,
and generally otherwise to improve the quality of the material. The peer review process can have limitations when considering research outside the conventional scientific paradigm: problems of "groupthink" can interfere
with open and fair deliberation of some new research.
Documentation and replication
Main article: Reproducibility
Sometimes experimenters may make systematic errors during their
experiments, unconsciously veer from scientific method (Pathological science) for various reasons, or, in rare cases, deliberately report false results. Consequently, it is a common practice for other scientists to attempt to repeat the experiments in order to duplicate the results, thus further validating the hypothesis.
As a result, researchers are expected to practice scientific data archiving in compliance with the policies of government funding agencies and scientific journals. Detailed records of their experimental
procedures, raw data, statistical analyses and source code are preserved in order to provide evidence of the effectiveness and integrity of the procedure and assist in reproduction. These procedural records may also assist in the conception of new experiments to test the hypothesis, and may prove useful to engineers who might examine the potential practical applications of a discovery.
When additional information is needed before a study can be reproduced, the author of the study is expected to provide it promptly. If the author refuses to share data, appeals can be made to the journal editors who published the study or to the institution which funded the research. Limitations
Since it is impossible for a scientist to record everything that took place in an experiment, facts selected for their apparent relevance are reported. This may lead, unavoidably, to problems later if some supposedly
irrelevant feature is questioned. For example, Heinrich Hertz did not report the size of the room used to test Maxwell's equations, which later turned out to account for a small deviation in the results. The problem is that parts of the theory itself need to be assumed in order to select
and report the experimental conditions. The observations are hence sometimes described as being 'theory-laden'.
Dimensions of practice
Further information: Rhetoric of science
The primary constraints on contemporary science are:
? Resources (mostly funding) ?
It has not always been like this: in the old days of the "gentleman scientist" funding (and to a lesser extent publication) were far weaker constraints.
Both of these constraints indirectly require scientific method – work that violates the constraints will be difficult to publish and difficult to get funded. Journals require submitted papers to conform to "good scientific practice" and this is mostly enforced by peer review.
Originality, importance and interest are more important – see for example the author guidelines for Nature.
Philosophy and sociology of science
Main articles: Philosophy of science and Sociology of science
Philosophy of science looks at the underpinning logic of the scientific method, at what separates science from non-science, and the ethic that is implicit in science. There are basic assumptions derived from
philosophy that form the base of the scientific method – namely, that reality is objective and consistent, that humans have the capacity to perceive reality accurately, and that rational explanations exist for elements of the real world. These assumptions from methodological naturalism form the basis on which science is grounded. Logical Positivist, empiricist, falsificationist, and other theories have claimed to give a definitive account of the logic of science, but each has in turn been criticized. Thomas Kuhn examined the history of science in his The Structure of Scientific Revolutions, and found that the actual method used by
scientists differed dramatically from the then-espoused method. His observations of science practice are essentially sociological and do not
speak to how science is or can be practiced in other times and other cultures.
Norwood Russell Hanson, Imre Lakatos and Thomas Kuhn have done extensive work on the "theory laden" character of observation. Hanson (1958) first coined the term for the idea that all observation is dependent on the conceptual framework of the observer, using the concept of gestalt to show
how preconceptions can affect both observation and description. He
opens Chapter 1 with a discussion of the Golgi bodies and their initial rejection as an artefact of staining technique, and a discussion of Brahe and Kepler observing the dawn and seeing a "different" sun rise despite the same physiological phenomenon. Kuhn and Feyerabend acknowledge the pioneering significance of his work.
Kuhn (1961) said the scientist generally has a theory in mind before designing and undertaking experiments so as to make empirical
observations, and that the "route from theory to measurement can almost never be traveled backward". This implies that the way in which theory is tested is dictated by the nature of the theory itself, which led Kuhn (1961, p. 166) to argue that "once it has been adopted by a profession ... no theory is recognized to be testable by any quantitative tests that it has not already passed". Paul Feyerabend similarly examined the history of science, and was led to deny that science is genuinely a methodological process. In his book Against Method he argues that scientific progress is not the result of applying any particular method. In essence, he says that for any specific method or norm of science, one can find a historic episode where violating it has contributed to the progress of science. Thus, if believers in scientific method wish to express a single universally valid rule,
Feyerabend jokingly suggests, it should be 'anything goes'. Criticisms such as his led to the strong programme, a radical approach to the sociology of science.
The postmodernist critiques of science have themselves been the subject of intense controversy. This ongoing debate, known as the science wars, is the result of conflicting values and assumptions between the
postmodernist and realist camps. Whereas postmodernists assert that scientific knowledge is simply another discourse (note that this term has special meaning in this context) and not representative of any form of fundamental truth, realists in the scientific community maintain that scientific knowledge does reveal real and fundamental truths about
reality. Many books have been written by scientists which take on this problem and challenge the assertions of the postmodernists while defending science as a legitimate method of deriving truth.
Role of chance in discovery
Main article: Role of chance in scientific discoveries
Somewhere between 33% and 50% of all scientific discoveries are estimated to have been stumbled upon, rather than sought out. This may explain why scientists so often express that they were lucky. Louis Pasteur is credited with the famous saying that "Luck favours the prepared mind", but some psychologists have begun to study what it means to be 'prepared for luck' in the scientific context. Research is showing that scientists are taught various heuristics that tend to harness chance and the
unexpected. This is what professor of economics Nassim Nicholas Taleb calls "Anti-fragility"; while some systems of investigation are fragile in the face of human error, human bias, and randomness, the scientific method is more than resistant or tough – it actually benefits from such randomness in many ways (it is anti-fragile). Taleb believes that the more anti-fragile the system, the more it will flourish in the real world.
Psychologist Kevin Dunbar says the process of discovery often starts with researchers finding bugs in their experiments. These unexpected results lead researchers to try and fix what they think is an error in their method. Eventually, the researcher decides the error is too persistent and systematic to be a coincidence. The highly controlled, cautious and curious aspects of the scientific method are thus what make it well suited for identifying such persistent systematic errors. At this point, the researcher will begin to think of theoretical explanations for the error, often seeking the help of colleagues across different domains of expertise.
Main article: History of scientific method
See also: Timeline of the history of scientific method
Aristotle, 384 BC–322 BC. "As regards his method, Aristotle is recognized as the inventor of scientific method because of his refined analysis of logical implications contained in demonstrative discourse, which goes well beyond natural logic and does not owe anything to the ones who philosophized before him." – Riccardo Pozzo
The development of the scientific method is inseparable from the history of science itself. Ancient Egyptian documents describe empirical methods in astronomy, mathematics, and medicine. In the 7th century BC Daniel, a Jewish captive of the Babylonian king Nebuchadnezzar, conducted a scientific experiment complete with a hypothesis, a control group, a treatment group, and a conclusion. The control group partook of the king’s delicacies and wine, whereas Daniel’s test group limited
themselves to vegetables and water. At the end of the test, Daniel’s hypothesis was proven true.
The ancient Greek philosopher Thales in the 6th century BC refused to accept supernatural, religious or mythological explanations for natural phenomena, proclaiming that every event had a natural cause. The
development of deductive reasoning by Plato was an important step towards the scientific method. Empiricism seems to have been formalized by Aristotle, who believed that universal truths could be reached via induction.
However in order for true scientific method to develop, Aristotle could not be taken at face value. Errors in his “On the Heavens” and
“Physics” had to be realized and corrected. Moreover, the pagan view common in the world during that era followed two concepts that prevented them from progressing toward a functional scientific method:
1. Organismic view of nature – nature and created objects are divine
or are themselves without beginning or end
2. Circular reasoning as opposed to linear reasoning.[discuss]
According to Haffner, cultures that were thus debilitated included
Chinese, Hindu, Meso-American, Egyptian, Babylonian, Greek and Arabic. We shall soon see how the basis for the emergence of a true scientific method was provided by the Judeo-Christian perspective. “The principles underlying the scientific method (testability,
verification/falsification) arise from the Judeo-Christian Scriptures. The experimental method was clearly nurtured by Christian doctrine." Early Christian leaders such as Clement of Alexandria (150–215) and Basil of Caesarea (330–379) encouraged future generations to view the Greek wisdom as “handmaidens to theology” and science was considered a means
to more accurate understanding of the Bible and of God.Augustine of Hippo (354–430) who contributed great philosophical wealth to the Latin Middle Ages, advocated the study of science and was wary of philosophies that disagreed with the Bible, such as astrology and the Greek belief that
the world had no beginning. This Christian accommodation with Greek
science “laid a foundation for the later widespread, intensive study of natural philosophy during the Late Middle Ages.” However the division of Latin-speaking Western Europe from the Greek-speaking East,
followed by barbarian invasions, the Plague of Justinian, and the Islamic invasion, resulted in the West largely losing access to Greek wisdom. By the 8th century Islam had overrun the Christian lands of Syria, Iraq,
Iran and Egypt This swift occupation further severed Western Europe
from many of the great works of Aristotle, Plato, Euclid and others. Having come upon such a wealth of knowledge, the Arabs, who viewed non-Arab languages as inferior, even as a source of pollution, employed
conquered Christians and Jews to translate these works from the native Greek and Syriac into Arabic
Thus equipped, Arab philosopher Alhazen performed optical and
physiological experiments, reported in his manifold works, the most famous being Book of Optics (1021). He was thus a forerunner of scientific method, having understood that a controlled environment
involving experimentation and measurement is required in order to draw educated conclusions. Other Arab polymaths of the same era produced copious works on mathematics, philosophy, astronomy and alchemy. Most stuck closely to Aristotle, being hesitant to admit that some of
Aristotle’s thinking was errant, while others strongly criticized him.
The source of the Arab difficulty in getting beyond Aristotle lay in the Islamic worldview. Akin to the polytheistic cultures mentioned above, folk traditions were widespread among the local population. Thus many
Muslims pursued astrology and followed the view that nature was alive and divine. Secondly, and of greater consequence, Muslim thinkers
labored against the theological understanding that Allah is unlimited and therefore liable to change, natural phenomenon thus being a direct product
of his unpredictable will.
In order to get to true scientific method, it was necessary for humankind to:
1. Find a balance in the interpretation of Aristotle and other ancient
philosophers – to glean, utilize and build upon their wisdom while yet being willing to criticize the mistakes
2. To liberate themselves from the perception that nature undergoes
constant divine intervention, recognizing instead that that it is governed by its own laws, albeit perhaps set in motion by God, yet otherwise driven by natural and therefore discoverable and knowable
The Judeo-Christian perspective, which embraced both of the above, thus fostered the eventual breakthrough into true scientific method. Though paraphrased translations from the Arabic, which itself had been translated from Greek and Syriac, made their way to the West, it wasn't until the Fourth Crusade when the West re-possessed Constantinople from the Muslims in 1204 that access was again gained to the original Greek texts. From that point a functional scientific method that would launch modern science was on the horizon. Grosseteste (1175–1253), an English statesman, scientist and Christian theologian, was "the principal figure" in bringing about "a more adequate method of scientific inquiry" by which "medieval scientists were able eventually to outstrip their ancient European and Muslim teachers" (Dales 1973:62). ... His thinking influenced Roger Bacon, who spread
Grosseteste's ideas from Oxford to the University of Paris during a visit there in the 1240s. From the prestigious universities in Oxford and Paris, the new experimental science spread rapidly throughout the medieval universities: "And so it went to Galileo, William Gilbert, Francis Bacon, William Harvey, Descartes, Robert Hooke, Newton, Leibniz, and the world of the seventeenth century" (Crombie 1962:15). So it went to us also.| Hugh G. Gauch, 2003.
Roger Bacon (c.1214–1294) is sometimes credited as one of the earliest European advocates of the modern scientific method inspired by the works of Aristotle. Roger Bacon (1214–1294), an English thinker and experimenter, is
recognized by many to be the father of modern scientific method. His view that mathematics was essential to a correct understanding of natural philosophy was considered to be 400 years ahead of its time. He was viewed as “a lone genius proclaiming the truth about time,” having correctly calculated the calendar His work in optics provided the platform on which Newton, Descartes, Huygens and others later transformed the science of light. Bacon’s groundbreaking advances were due largely to his discovery that experimental science must be based on mathematics. (186–187) His works Opus Majus and De Speculis Comburentibus contain many “carefully drawn diagrams showing Bacon’s meticulous investigations into the behavior of light.” He gives detailed descriptions of
systematic studies using prisms and measurements by which he shows how a rainbow functions.
Others who advanced scientific method during this era included Albertus Magnus (c.1193–1280), Theodoric of Freiberg, (c.1250–c.1310), William of Ockham (c.1285–c.1350), and Jean Buridan (c.1300–c.1358). These were not only scientists but leaders of the church – Christian archbishops, friars and priests.
By the late 15th century, the physician-scholar Niccolò Leoniceno was finding errors in Pliny's Natural History. As a physician, Leoniceno was concerned about these botanical errors propagating to the materia medica on which medicines were based. To counter this, a botanical garden was established at Orto botanico di Padova, University of Padua (in use for teaching by 1546), in order that medical students might have empirical access to the plants of a pharmacopia. The philosopher and physician Francisco Sanches was led by his medical training at Rome, 1571–73, and by the philosophical skepticism recently placed in the European mainstream by the publication of Sextus Empiricus' "Outlines of
Pyrrhonism", to search for a true method of knowing (modus sciendi), as
nothing clear can be known by the methods of Aristotle and his followers – for example, syllogism fails upon circular reasoning. Following the physician Galen's method of medicine, Sanches lists the methods of
judgement and experience, which are faulty in the wrong hands, and we are left with the bleak statement That Nothing is Known (1581). This challenge was taken up by René Descartes in the next generation (1637), but at the least, Sanches warns us that we ought to refrain from the methods, summaries, and commentaries on Aristotle, if we seek scientific knowledge. In this, he is echoed by Francis Bacon, also influenced by skepticism; Sanches cites the humanist Juan Luis Vives who sought a better educational system, as well as a statement of human rights as a pathway for improvement of the lot of the poor.
The modern scientific method crystallized no later than in the 17th and 18th centuries. In his work Novum Organum (1620) – a reference to
Aristotle's Organon – Francis Bacon outlined a new system of logic to improve upon the old philosophical process of syllogism. Then, in 1637, René Descartes established the framework for scientific method's guiding principles in his treatise, Discourse on Method. The writings of Alhazen, Bacon and Descartes are considered critical in the historical development of the modern scientific method, as are those of John Stuart Mill. In the late 19th century, Charles Sanders Peirce proposed a schema that would turn out to have considerable influence in the development of current scientific methodology generally. Peirce accelerated the
progress on several fronts. Firstly, speaking in broader context in "How to Make Our Ideas Clear" (1878), Peirce outlined an objectively verifiable method to test the truth of putative knowledge on a way that goes beyond mere foundational alternatives, focusing upon both deduction and induction. He thus placed induction and deduction in a complementary rather than competitive context (the latter of which had been the primary trend at least since David Hume, who wrote in the mid-to-late 18th century). Secondly, and of more direct importance to modern method, Peirce put forth the basic schema for hypothesis/testing that continues to prevail today. Extracting the theory of inquiry from its raw materials in classical logic, he refined it in parallel with the early development of symbolic logic to address the then-current problems in scientific reasoning. Peirce examined and articulated the three fundamental modes of reasoning that, as discussed above in this article, play a role in inquiry today, the processes that are currently known as abductive, deductive, and inductive inference. Thirdly, he played a major role in the progress of symbolic logic itself – indeed this was his primary specialty.
Beginning in the 1930s, Karl Popper argued that there is no such thing as inductive reasoning. All inferences ever made, including in science,
are purely deductive according to this view. Accordingly, he claimed that the empirical character of science has nothing to do with induction – but with the deductive property of falsifiability that scientific hypotheses have. Contrasting his views with inductivism and positivism, he even denied the existence of the scientific method: "(1) There is no method of discovering a scientific theory (2) There is no method for ascertaining the truth of a scientific hypothesis, i.e., no method of verification; (3) There is no method for ascertaining whether a hypothesis is 'probable', or probably true". Instead, he held that there is only one universal method, a method not particular to science: The negative method of criticism, or colloquially termed trial and error. It covers not only all products of the human mind, including science, mathematics, philosophy, art and so on, but also the evolution of life. Following Peirce and others, Popper argued that science is fallible and has no authority. In contrast to empiricist-inductivist views, he welcomed metaphysics and philosophical discussion and even gave qualified support to myths and
pseudosciences. Popper's view has become known as critical rationalism.
Although science in a broad sense existed before the modern era, and in many historical civilizations (as described above), modern science is so distinct in its approach and successful in its results that it now defines what science is in the strictest sense of the term.
Relationship with mathematics
Science is the process of gathering, comparing, and evaluating proposed models against observables. A model can be a simulation, mathematical or chemical formula, or set of proposed steps. Science is like mathematics in that researchers in both disciplines can clearly distinguish what is known from what is unknown at each stage of discovery. Models, in both science and mathematics, need to be internally consistent and also ought to be falsifiable (capable of disproof). In mathematics, a statement need not yet be proven; at such a stage, that statement would be called a conjecture. But when a statement has attained mathematical proof, that statement gains a kind of immortality which is highly prized by
mathematicians, and for which some mathematicians devote their lives. Mathematical work and scientific work can inspire each other. For example, the technical concept of time arose in science, and timelessness was a hallmark of a mathematical topic. But today, the Poincaré conjecture has been proven using time as a mathematical concept in which objects can flow (see Ricci flow).
Nevertheless, the connection between mathematics and reality (and so science to the extent it describes reality) remains obscure. Eugene Wigner's paper, The Unreasonable Effectiveness of Mathematics in the Natural Sciences, is a very well known account of the issue from a Nobel Prize-winning physicist. In fact, some observers (including some well known mathematicians such as Gregory Chaitin, and others such as Lakoff and Nú?ez) have suggested that mathematics is the result of practitioner bias and human limitation (including cultural ones), somewhat like the post-modernist view of science. George Pólya's work on problem solving, the construction of
mathematical proofs, and heuristic show that the mathematical method and the scientific method differ in detail, while nevertheless resembling each other in using iterative or recursive steps.
Mathematical method 1 Understanding 2 Analysis 3 Synthesis 4 Review/Extend Scientific method Characterization from experience and observation Hypothesis: a proposed explanation Deduction: prediction from the hypothesis Test and experiment
In Pólya's view, understanding involves restating unfamiliar definitions in your own words, resorting to geometrical figures, and questioning what we know and do not know already; analysis, which Pólya takes from Pappus, involves free and heuristic construction of plausible arguments, working backward from the goal, and devising a plan for constructing the proof; synthesis is the strict Euclidean exposition of step-by-step details of the proof; review involves reconsidering and re-examining the result and the path taken to it. Gauss, when asked how he came about his theorems, once replied "durch planm?ssiges Tattonieren" (through systematic palpable experimentation). Imre Lakatos argued that mathematicians actually use contradiction, criticism and revision as principles for improving their work. See also
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2. 3. 4.
6. 7. 8. ^ Jump up to: a b Goldhaber & Nieto 2010, p. 940 Jump up ^ " Rules for the study of natural philosophy", Newton 1999, pp. 794–6, from Book 3, The System of the World. Jump up ^ Oxford English Dictionary – entry for scientific. Jump up ^ Morris Kline (1985) Mathematics for the nonmathematician. Courier Dover Publications. p. 284. ISBN 0-486-24823-2 Jump up ^ Shapere, Dudley (1974). Galileo: A Philosophical Study. University of Chicago Press. ISBN 0-226-75007-8. Jump up ^ Peirce, C. S., Collected Papers v. 1, paragraph 74. Jump up ^ Popper, Karl (1998). The world of Parmenides: essays on the Presocratic enlightenment. Routledge. p. 91. ISBN 0415173019. Jump up ^ Lindberg, David (2007). The beginnings of western science:
the European scientific tradition in philosophical, religious, and institutional context, Prehistory to A.D. 1450. The University of Chicago Press. p. 362. ISBN 0226482057.
9. Jump up ^ Losee, John (2001). A Historical Introduction to the
Philosophy of Science. Oxford University Press. pp. 4–5. ISBN 0198700555.
10. Jump up ^ " The thesis of this book, as set forth in Chapter One,
is that there are general principles applicable to all the sciences." __ Gauch 2003, p. xv
11. ^ Jump up to: a b c Peirce (1877), "The Fixation of Belief", Popular
Science Monthly, v. 12, pp. 1–15. Reprinted often, including (Collected Papers of Charles Sanders Peirce v. 5, paragraphs 358–87), (The
Essential Peirce, v. 1, pp. 109–23). Peirce.org Eprint. Wikisource Eprint.
12. Jump up ^ Gauch 2003, p. 1: This is the principle of
13. ^ Jump up to: a b Peirce, C. S., Collected Papers v. 5, in paragraph
582, from 1898:
... [rational] inquiry of every type, fully carried out, has the vital power of self-correction and of growth. This is a property so deeply saturating its inmost nature that it may truly be said that there is but one thing needful for learning the truth, and that is a hearty and active desire to learn what is true.
14. ^ Jump up to: a b Taleb contributes a brief description of
15. Jump up ^ Karl R. Popper (1963), 'The Logic of Scientific
Discovery'. The Logic of Scientific Discovery pp. 17–20, 249–252, 437–438, and elsewhere.
? , for teaching , illustrates how
to avoid confirmation bias: Ian Shelton, in Chile, was initially
skeptical that supernova 1987a was real, but possibly an artifact
of instrumentation (null hypothesis), so he went outside and
disproved his null hypothesis by observing SN 1987a with the naked
eye. The Kamiokande experiment, in Japan, independently observed neutrinos from SN 1987a at the same time.
ab16. ^ Jump up to: Peirce (1908), "A Neglected Argument for the
Reality of God", Hibbert Journal v. 7, pp. 90–112. s:A Neglected Argument for the Reality of God with added notes. Reprinted with previously unpublished part, Collected Papers v. 6, paragraphs 452-85, The Essential Peirce v. 2, pp. 434–50, and elsewhere.
17. Jump up ^ Gauch 2003, p. 3
18. Jump up ^ History of Inductive Science (1837), and in Philosophy
of Inductive Science (1840)
19. Jump up ^ Schuster and Powers (2005), Translational and
Experimental Clinical Research, Ch. 1. Link. This chapter also discusses the different types of research questions and how they are produced.
20. Jump up ^ This phrasing is attributed to Marshall Nirenberg.
21. Jump up ^ Karl R. Popper, Conjectures and Refutations: The Growth
of Scientific Knowledge, Routledge, 2003 ISBN 0-415-28594-1
22. Jump up ^ Lindberg 2007, pp. 2–3: "There is a danger that must
be avoided. ... If we wish to do justice to the historical enterprise, we must take the past for what it was. And that means we must resist the temptation to scour the past for examples or precursors of modern
science. ...My concern will be with the beginnings of scientific theories, the methods by which they were formulated, and the uses to which they were put; ... "
23. Jump up ^ "How does light travel through transparent bodies? Light
travels through transparent bodies in straight lines only.... We have explained this exhaustively in our Book of Optics. But let us now mention something to prove this convincingly: the fact that light travels in straight lines is clearly observed in the lights which enter into dark rooms through holes.... [T]he entering light will be clearly observable in the dust which fills the air. – Alhazen, translated into English from German by M. Schwarz, from "Abhandlung über das Licht", J. Baarmann (ed. 1882) Zeitschrift der Deutschen Morgenl?ndischen Gesellschaft Vol 36 as quoted in Sambursky 1974, p. 136.
He demonstrated his conjecture that "light travels through
transparent bodies in straight lines only" by placing a straight
stick or a taut thread next to the light beam, as quoted in Sambursky 1974, p. 136 to prove that light travels in a straight
? , (2001, 2006) in Secret Knowledge:
rediscovering the lost techniques of the old masters ISBN 0-14-200512-6 (expanded edition) cites Alhazen several times as
the likely source for the portraiture technique using the camera obscura, which Hockney rediscovered with the aid of an optical
suggestion from Charles M. Falco. Kitab al-Manazir, which is
Alhazen's Book of Optics, at that time denoted Opticae Thesaurus,
Alhazen Arabis, was translated from Arabic into Latin for European
use as early as 1270. Hockney cites Friedrich Risner's 1572 Basle
edition of Opticae Thesaurus. Hockney quotes Alhazen as the first
clear description of the camera obscura in Hockney, p. 240. ?
"Truth is sought for its own sake. And those who are engaged upon the quest for anything for its own sake are not interested in other things. Finding the truth is difficult, and the road to it is rough." – Alhazen (Ibn Al-Haytham 965–c.1040) Critique of Ptolemy, translated by S. Pines, Actes X Congrès internationale d'histoire des sciences, Vol I Ithaca 1962, as quoted in Sambursky 1974, p. 139. (This quotation is from Alhazen's critique of Ptolemy's books Almagest, Planetary Hypotheses, and Optics as translated into English by A. Mark Smith.)
Jump up ^ Galilei, Galileo (M.D.C.XXXVIII), Discorsi e
Dimonstrazioni Matematiche, intorno a due nuoue scienze, Leida: Apresso gli Elsevirri, ISBN 0-486-60099-8, Dover reprint of the 1914 Macmillan translation by Henry Crew and Alfonso de Salvio of Two New Sciences, Galileo Galilei Linceo (1638). Additional publication information is from the collection of first editions of the Library of Congress surveyed by Bruno 1989, pp. 261–264.
25. Jump up ^ Godfrey-Smith 2003 p. 236.
26. ^ Jump up to: a b McCarty1985
27. Jump up ^ October 1951, as noted in McElheny 2004, p. 40:"That's
what a helix should look like!" Crick exclaimed in delight (This is the Cochran-Crick-Vand-Stokes theory of the transform of a helix).
28. Jump up ^ June 1952, as noted in McElheny 2004, p. 43: Watson had
succeeded in getting X-ray pictures of TMV showing a diffraction pattern consistent with the transform of a helix.
29. ^ Jump up to: a b Watson did enough work on Tobacco mosaic virus
to produce the diffraction pattern for a helix, per Crick's work on the 24.
transform of a helix. pp. 137–138, Horace Freeland Judson (1979) The Eighth Day of Creation ISBN 0-671-22540-5
30. ^ Jump up to: a b – Cochran W, Crick FHC and Vand V. (1952) "The
Structure of Synthetic Polypeptides. I. The Transform of Atoms on a Helix", Acta Cryst., 5, 581–586.
31. ^ Jump up to: a b Friday, January 30, 1953. Tea time, as noted in McElheny 2004, p. 52: Franklin confronts Watson and his paper – "Of course it [Pauling's pre-print] is wrong. DNA is not a helix." However, Watson then visits Wilkins' office, sees photo 51, and immediately recognizes the diffraction pattern of a helical structure. But additional questions remained, requiring additional iterations of their research. For example, the number of strands in the backbone of the helix (Crick suspected 2 strands, but cautioned Watson to examine that more
critically), the location of the base pairs (inside the backbone or outside the backbone), etc. One key point was that they realized that the quickest way to reach a result was not to continue a mathematical analysis, but to build a physical model.
32. ^ Jump up to: a b "The instant I saw the picture my mouth fell open
and my pulse began to race." – Watson 1968, p. 167 Page 168 shows the X-shaped pattern of the B-form of DNA, clearly indicating crucial details of its helical structure to Watson and Crick.
? p.52 dates the Franklin-Watson confrontation
as Friday, January 30, 1953. Later that evening, Watson urges
Wilkins to begin model-building immediately. But Wilkins agrees
to do so only after Franklin's departure.
33. ^ Jump up to: a b Saturday, February 28, 1953, as noted in McElheny 2004, pp. 57–59: Watson found the base pairing mechanism which explained Chargaff's rules using his cardboard models.
34. Jump up ^ Fleck 1979, pp. xxvii–xxviii
35. Jump up ^ "NIH Data Sharing Policy."
36. Jump up ^ Stanovich, Keith E. (2007). How to Think Straight About
Psychology. Boston: Pearson Education. pg 123
37. ^ Jump up to: a b Brody 1993, pp. 44–45
38. Jump up ^ Hall, B. K.; Hallgrímsson, B., eds. (2008). Strickberger's Evolution (4th ed.). Jones & Bartlett. p. 762. ISBN 0-7637-0066-5.
39. Jump up ^ Cracraft, J.; Donoghue, M. J., eds. (2005). Assembling the tree of life. Oxford University Press. p. 592. ISBN 0-19-517234-5.
40. Jump up ^ Needham & Wang 1954 p.166 shows how the 'flying gallop'
image propagated from China to the West.
41. Jump up ^ "A myth is a belief given uncritical acceptance by members
of a group ..." – Weiss, Business Ethics p. 15, as cited by Ronald R. Sims (2003) Ethics and corporate social responsibility: why giants fall p.21
42. Jump up ^ Imre Lakatos (1976), Proofs and Refutations. Taleb 2007,
p. 72 lists ways to avoid narrative fallacy and confirmation bias.
43. Jump up ^ For more on the narrative fallacy, see also Fleck 1979,
p. 27: "Words and ideas are originally phonetic and mental equivalences of the experiences coinciding with them. ... Such proto-ideas are at first always too broad and insufficiently specialized. ... Once a structurally complete and closed system of opinions consisting of many details and relations has been formed, it offers enduring resistance to anything that contradicts it."
44. Jump up ^ "Invariably one came up against fundamental physical
limits to the accuracy of measurement. ... The art of physical measurement seemed to be a matter of compromise, of choosing between reciprocally related uncertainties. ... Multiplying together the conjugate pairs of uncertainty limits mentioned, however, I found that they formed invariant products of not one but two distinct kinds. ... The first group of limits were calculable a priori from a specification of the instrument. The second group could be calculated only a posteriori from a specification of what was done with the instrument. ... In the first case each unit
[of information] would add one additional dimension (conceptual
category), whereas in the second each unit would add one additional atomic fact.", – pp. 1–4: MacKay, Donald M. (1969), Information, Mechanism, and Meaning, Cambridge, MA: MIT Press, ISBN 0-262-63-032-X
45. Jump up ^ See the hypothethico-deductive method, for example, Godfrey-Smith 2003, p. 236.
46. Jump up ^ Jevons 1874, pp. 265–6.
47. Jump up ^ pp. 65,73, 92, 398 – Andrew J. Galambos, Sic Itur ad
Astra ISBN 0-88078-004-5(AJG learned scientific method from Felix Ehrenhaft
48. Jump up ^ Galileo 1638, pp. v–xii,1–300
49. Jump up ^ Brody 1993, pp. 10–24 calls this the "epistemic cycle":
"The epistemic cycle starts from an initial model; iterations of the cycle then improve the model until an adequate fit is achieved."
50. Jump up ^ Iteration example: Chaldean astronomers such as Kidinnu
compiled astronomical data. Hipparchus was to use this data to calculate the precession of the Earth's axis. Fifteen hundred years after Kidinnu, Al-Batani, born in what is now Turkey, would use the collected data and improve Hipparchus' value for the precession of the Earth's axis. Al-Batani's value, 54.5 arc-seconds per year, compares well to the current value of 49.8 arc-seconds per year (26,000 years for Earth's axis to round the circle of nutation).
51. Jump up ^ Recursion example: the Earth is itself a magnet, with
its own North and South Poles William Gilbert (in Latin 1600) De Magnete, or On Magnetism and Magnetic Bodies. Translated from Latin to English, selection by Moulton & Schifferes 1960, pp. 113–117. Gilbert created
a terrella, a lodestone ground into a spherical shape, which served as Gilbert's model for the Earth itself, as noted in Bruno 1989, p. 277.
52. Jump up ^ "The foundation of general physics ... is experience.
These ... everyday experiences we do not discover without deliberately directing our attention to them. Collecting information about these is observation." – Hans Christian ?rsted("First Introduction to General Physics" ?13, part of a series of public lectures at the University of Copenhagen. Copenhagen 1811, in Danish, printed by Johan Frederik Schulz. In Kirstine Meyer's 1920 edition of ?rsted's works, vol.III pp. 151–190. ) "First Introduction to Physics: the Spirit, Meaning, and Goal of Natural Science". Reprinted in German in 1822, Schweigger's Journal für Chemie und Physik 36, pp. 458–488, as translated in ?rsted 1997, p. 292
53. Jump up ^ "When it is not clear under which law of nature an effect
or class of effect belongs, we try to fill this gap by means of a guess. Such guesses have been given the name conjectures or hypotheses." – Hans Christian ?rsted(1811) "First Introduction to General Physics" as translated in ?rsted 1997, p. 297.
54. Jump up ^ "In general we look for a new law by the following process.
First we guess it. ...", – Feynman 1965, p. 156
55. Jump up ^ "... the statement of a law – A depends on B – always
transcends experience." – Born 1949, p. 6
56. Jump up ^ "The student of nature ... regards as his property the
experiences which the mathematician can only borrow. This is why he deduces theorems directly from the nature of an effect while the
mathematician only arrives at them circuitously." – Hans Christian ?rsted(1811) "First Introduction to General Physics" ?17. as translated in ?rsted 1997, p. 297.
57. Jump up ^ Salviati speaks: "I greatly doubt that Aristotle ever
tested by experiment whether it be true that two stones, one weighing ten times as much as the other, if allowed to fall, at the same instant, from a height of, say, 100 cubits, would so differ in speed that when the heavier had reached the ground, the other would not have fallen more than 10 cubits." Two New Sciences (1638) – Galileo 1638, pp. 61–62.
A more extended quotation is referenced by Moulton & Schifferes 1960, pp. 80–81.
58. Jump up ^ In the inquiry-based education paradigm, the stage of
"characterization, observation, definition, ?" is more briefly summed up under the rubric of a Question
59. Jump up ^ "To raise new questions, new possibilities, to regard
old problems from a new angle, requires creative imagination and marks real advance in science." – Einstein & Infeld 1938, p. 92.
60. Jump up ^ Crawford S, Stucki L (1990), "Peer review and the changing
research record", "J Am Soc Info Science", vol. 41, pp. 223–228
61. Jump up ^ See, e.g., Gauch 2003, esp. chapters 5–8
62. Jump up ^ Cartwright, Nancy (1983), How the Laws of Physics Lie.
Oxford: Oxford University Press. ISBN 0-19-824704-4
63. Jump up ^ Andreas Vesalius, Epistola, Rationem, Modumque
Propinandi Radicis Chynae Decocti (1546), 141. Quoted and translated in
C.D. O'Malley, Andreas Vesalius of Brussels, (1964), 116. As quoted by Bynum & Porter 2005, p. 597: Andreas Vesalius,597#1.
64. Jump up ^ Crick, Francis (1994), The Astonishing Hypothesis ISBN 0-684-19431-7 p.20
65. Jump up ^ McElheny 2004 p.34
66. Jump up ^ Glen 1994, pp. 37–38.
67. Jump up ^ "The structure that we propose is a three-chain structure,
each chain being a helix" – Linus Pauling, as quoted on p. 157 by Horace Freeland Judson (1979), The Eighth Day of Creation ISBN 0-671-22540-5
68. Jump up ^ McElheny 2004, pp. 49–50: January 28, 1953 – Watson
read Pauling's pre-print, and realized that in Pauling's model, DNA's phosphate groups had to be un-ionized. But DNA is an acid, which
contradicts Pauling's model.
69. Jump up ^ June 1952. as noted in McElheny 2004, p. 43: Watson had
succeeded in getting X-ray pictures of TMV showing a diffraction pattern consistent with the transform of a helix.
70. Jump up ^ McElheny 2004 p.68: Nature April 25, 1953.
71. Jump up ^ In March 1917, the Royal Astronomical Society announced
that on May 29, 1919, the occasion of a total eclipse of the sun would afford favorable conditions for testing Einstein's General theory of relativity. One expedition, to Sobral, Ceará, Brazil, and Eddington's expedition to the island of Principe yielded a set of photographs, which, when compared to photographs taken at Sobral and at Greenwich Observatory showed that the deviation of light was measured to be 1.69 arc-seconds, as compared to Einstein's desk prediction of 1.75 arc-seconds. –
Antonina Vallentin (1954), Einstein, as quoted by Samuel Rapport and Helen Wright (1965), Physics, New York: Washington Square Press, pp 294–295.
72. Jump up ^ Mill, John Stuart, "A System of Logic", University Press
of the Pacific, Honolulu, 2002, ISBN 1-4102-0252-6.
73. Jump up ^ al-Battani, De Motu Stellarum translation from Arabic to Latin in 1116, as cited by "Battani, al-" (c.858–929) Encyclopaedia Britannica, 15th. ed. Al-Battani is known for his accurate observations at al-Raqqah in Syria, beginning in 877. His work includes measurement of the annual precession of the equinoxes.
74. Jump up ^ McElheny 2004 p.53: The weekend (January 31 – February
1) after seeing photo 51, Watson informed Bragg of the X-ray diffraction image of DNA in B form. Bragg gave them permission to restart their research on DNA (that is, model building).
75. Jump up ^ McElheny 2004 p.54: On Sunday February 8, 1953, Maurice
Wilkes gave Watson and Crick permission to work on models, as Wilkes would not be building models until Franklin left DNA research.
76. Jump up ^ McElheny 2004 p.56: Jerry Donohue, on sabbatical from
Pauling's lab and visiting Cambridge, advises Watson that textbook form of the base pairs was incorrect for DNA base pairs; rather, the keto form of the base pairs should be used instead. This form allowed the bases' hydrogen bonds to pair 'unlike' with 'unlike', rather than to pair 'like' with 'like', as Watson was inclined to model, on the basis of the textbook statements. On February 27, 1953, Watson was convinced enough to make cardboard models of the nucleotides in their keto form.
77. Jump up ^ "Suddenly I became aware that an adenine-thymine pair
held together by two hydrogen bonds was identical in shape to a guanine-cytosine pair held together by at least two hydrogen bonds. ..." – Watson 1968, pp. 194–197.
? p.57 Saturday, February 28, 1953, Watson
tried 'like with like' and admited these base pairs didn't have
hydrogen bonds that line up. But after trying 'unlike with unlike',
and getting Jerry Donohue's approval, the base pairs turned out
to be identical in shape (as Watson stated above in his 1968 Double
Helix memoir quoted above). Watson now felt confident enough to
inform Crick. (Of course, 'unlike with unlike' increases the
number of possible codons, if this scheme were a genetic code.)
78. Jump up ^ See, e.g., Physics Today, 59(1), p42. Richmann electrocuted in St. Petersburg (1753)
79. Jump up ^ Aristotle, "Prior Analytics", Hugh Tredennick (trans.),
pp. 181–531 in Aristotle, Volume 1, Loeb Classical Library, William Heinemann, London, UK, 1938.
80. Jump up ^ "What one does not in the least doubt one should not
pretend to doubt; but a man should train himself to doubt," said Peirce in a brief intellectual autobiography; see Ketner, Kenneth Laine (2009) "Charles Sanders Peirce: Interdisciplinary Scientist" in The Logic of Interdisciplinarity). Peirce held that actual, genuine doubt originates externally, usually in surprise, but also that it is to be sought and cultivated, "provided only that it be the weighty and noble metal itself, and no counterfeit nor paper substitute"; in "Issues of Pragmaticism", The Monist, v. XV, n. 4, pp. 481–99, see p. 484, and p. 491. (Reprinted in Collected Papers v. 5, paragraphs 438-63, see 443 and 451).
81. Jump up ^ Peirce (1898), "Philosophy and the Conduct of Life",
Lecture 1 of the Cambridge (MA) Conferences Lectures, published in Collected Papers v. 1, paragraphs 616-48 in part and in Reasoning and the Logic of Things, Ketner (ed., intro.) and Putnam (intro., comm.), pp. 105–22, reprinted in Essential Peirce v. 2, pp. 27–41.
82. Jump up ^ " ... in order to learn, one must desire to learn ..."
– Peirce (1899), "F.R.L." [First Rule of Logic], Collected Papers v. 1, paragraphs 135-40, Eprint
abc83. ^ Jump up to: Peirce (1877), "How to Make Our Ideas Clear",
Popular Science Monthly, v. 12, pp. 286–302. Reprinted often, including Collected Papers v. 5, paragraphs 388–410, Essential Peirce v. 1, pp. 124–41. ArisbeEprint. Wikisource Eprint.
84. Jump up ^ Peirce (1868), "Some Consequences of Four Incapacities",
Journal of Speculative Philosophy v. 2, n. 3, pp. 140–57. Reprinted Collected Papers v. 5, paragraphs 264–317, The Essential Peirce v. 1, pp. 28–55, and elsewhere. Arisbe Eprint
85. Jump up ^ Peirce (1878), "The Doctrine of Chances", Popular Science
Monthly v. 12, pp. 604–15, see pp. 610-11 via Internet Archive. Reprinted Collected Papers v. 2, paragraphs 645-68, Essential Peirce v. 1, pp. 142–54. "...death makes the number of our risks, the number of our inferences, finite, and so makes their mean result uncertain. The very idea of probability and of reasoning rests on the assumption that this number is indefinitely great. .... ...logicality inexorably requires that our interests shall not be limited. .... Logic is rooted in the social principle."
86. Jump up ^ Peirce (c. 1906), "PAP (Prolegomena for an Apology to
Pragmatism)" (Manuscript 293, not the like-named article), The New Elements of Mathematics (NEM) 4:319–320, see first quote under
"Abduction" at Commens Dictionary of Peirce's Terms.
87. Jump up ^ Peirce, Carnegie application (L75, 1902), New Elements
of Mathematics v. 4, pp. 37–38:
For it is not sufficient that a hypothesis should be a justifiable one. Any hypothesis which explains the facts is justified critically. But among justifiable hypotheses we have to select that one which is suitable for being tested by experiment.
88. ^ Jump up to: Peirce (1902), Carnegie application, see MS
L75.329–330, from Draft D of Memoir 27:
Consequently, to discover is simply to expedite an event that would occur sooner or later, if we had not troubled ourselves to make the discovery. Consequently, the art of discovery is purely a question of economics. The economics of research is, so far as logic is concerned, the leading doctrine with reference to the art of discovery. Consequently, the conduct of abduction, which is chiefly a question of heuretic and is the first question of heuretic, is to be governed by economical
89. Jump up ^ Peirce (1903), "Pragmatism – The Logic of Abduction",
Collected Papers v. 5, paragraphs 195–205, especially 196. Eprint.
90. Jump up ^ Peirce, "On the Logic of Drawing Ancient History from
Documents", Essential Peirce v. 2, see pp. 107–9. On Twenty Questions, p. 109:
Thus, twenty skillful hypotheses will ascertain what 200,000 stupid ones might fail to do.
Jump up ^ Peirce (1878), "The Probability of Induction", Popular
Science Monthly, v. 12, pp. 705–18, see 718 Google Books; 718 via Internet Archive. Reprinted often, including (Collected Papers v. 2, paragraphs 669-93), (The Essential Peirce v. 1, pp. 155–69).
92. Jump up ^ Peirce (1905 draft "G" of "A Neglected Argument"), "Crude,
Quantitative, and Qualitative Induction", Collected Papers v. 2,
paragraphs 755–760, see 759. Find under "Induction" at Commens
Dictionary of Peirce's Terms.
93. Jump up ^ . Brown, C. (2005) Overcoming Barriers to Use of Promising
Research Among Elite Middle East Policy Groups, Journal of Social
Behaviour and Personality, Select Press.
94. Jump up ^ Hanson, Norwood (1958), Patterns of Discovery, Cambridge
University Press, ISBN 0-521-05197-5
95. Jump up ^ Kuhn 1962, p. 113 ISBN 978-1-4432-5544-8
96. Jump up ^ Feyerabend, Paul K (1960) "Patterns of Discovery" The
Philosophical Review (1960) vol. 69 (2) pp. 247–252
97. Jump up ^ Kuhn, Thomas S., "The Function of Measurement in Modern
Physical Science", ISIS 52(2), 161–193, 1961.
98. Jump up ^ Feyerabend, Paul K., Against Method, Outline of an
Anarchistic Theory of Knowledge, 1st published, 1975. Reprinted, Verso, London, UK, 1978.
99. Jump up ^ 91. Higher Superstition: The Academic Left and Its Quarrels
with Science, The Johns Hopkins University Press, 1997
? Fashionable Nonsense: Postmodern Intellectuals' Abuse of
Science, Picador; 1st Picador USA Pbk. Ed edition, 1999
? The Sokal Hoax: The Sham That Shook the Academy, University ?
of Nebraska Press, 2000 ISBN 0-8032-7995-7
A House Built on Sand: Exposing Postmodernist Myths About
Science, Oxford University Press, 2000
? Intellectual Impostures, Economist Books, 2003 ?
100. ^ Jump up to: a b c Dunbar, K., & Fugelsang, J. (2005). Causal
thinking in science: How scientists and students interpret the unexpected. In M. E. Gorman, R. D. Tweney, D. Gooding & A. Kincannon (Eds.), Scientific
and Technical Thinking (pp. 57–79). Mahwah, NJ: Lawrence Erlbaum
101. ^ Jump up to: a b Oliver, J.E. (1991) Ch2. of The incomplete guide
to the art of discovery. New York:NY, Columbia University Press.
102. Jump up ^ Riccardo Pozzo (2004) The impact of Aristotelianism on modern philosophy. CUA Press. p.41. ISBN 0-8132-1347-9
103. Jump up ^ The ancient Egyptians observed that heliacal rising of
a certain star, Sothis (Greek for Sopdet (Egyptian), known to the West as Sirius), marked the annual flooding of the Nile river. See Neugebauer, Otto (1969) , The Exact Sciences in Antiquity (2 ed.), Dover Publications, ISBN 978-0-486-22332-2, p.82, and also the 1911 Britannica, "Egypt".
104. Jump up ^ The Rhind papyrus lists practical examples in arithmetic
and geometry – 1911 Britannica, "Egypt".
105. Jump up ^ The Ebers papyrus lists some of the 'mysteries of the
physician', as cited in the 1911 Britannica, "Egypt"
106. Jump up ^ Holy Bible, Book of Daniel 1:8–16
107. Jump up ^ Haffner, Paul. “Mystery of the Church”. Gracewing,
Herefordshire, UK, 2007, p. 263.
108. Jump up ^ Woodward, Kenneth L. “How the Heavens Go.” Newsweek,
July 20, 1998, p. 52.
109. ^ Jump up to: a b c d Grant, Edward. “The Foundations of Modern Science in the Middle Ages”. Cambridge University Press, UK, pp. 4–5. 110. Jump up ^ Hodges, Richard and David Whitehouse. “Mohammed,
Charlemagne and the Origins of Europe”. Cornell University Press, Ithaca, NY, 1983, p. 76.
111. Jump up ^ Lewis, Bernard. “Muslim Discovery of Europe”. W. W.
Norton and Company Ltd., New York, NY, 2001, p. 74.
112. Jump up ^ Dowley, Tim, Ed. “The Baker Atlas of Christian
History.” 2001, p. 89
113. Jump up ^ Lewis, Muslim Discovery, p. 72.
114. Jump up ^ Meri, Josef W. and Jere L. Bacharach. “Medieval Islamic
Civilization”. Vol. 1 Index A – K. 2006, p. 304.
115. Jump up ^ R. L. Verma (1969). Al-Hazen: father of modern optics. 116. Jump up ^ Jaki, Stanley. “Science and Creation: From Eternal Cycles to an Oscillating Universe”. Science History Publications, NY, 1974, p. 206.
117. Jump up ^ Glick, Thomas F. “George Sarton and the Spanish
Arabists.” 1985, p. 497.
118. Jump up ^ See "The Study of Astrology" section in "Astronomy and
Astrology in the Medieval Islamic World", The Metropolitan Museum of Art website, Accessed July 2013.
119. Jump up ^ Jaki, Science and Creation, pp. 204–205.
120. Jump up ^ “Some of the philosophical presuppositions foundational
to the study of science include these: the existence of an objectively real world, the comprehensibility of that world, the reliability of sense perception and human rationality, the orderliness and uniformity of nature, and the validity of mathematics and logic.” Hummel, Charles E. “The Galileo Connection.” Inter Varsity Press: Downers Grove, IL, 1986, pp. 158–159.
121. Jump up ^ Alfred North Whitehead, a renowned philosopher,
considered Christianity to be the "mother of science" on account of its insistence on the rationality of God. | Schaeffer, Francis A. “How Should We Then Live.”1976, p. 132.
122. Jump up ^ "Entomologist Stanley Beck, though not a Christian
himself, acknowledged the corner-stone premises of science which the Judeo-Christian world view offers: 'The first of the unprovable premises on which science has been based is the belief that the world is real and the human mind is capable of knowing its real nature. The second and best-known postulate underlying the structure of scientific knowledge is that of cause and effect. The third basic scientific premise is that nature is unified.'" | Morris, Henry M. “Biblical Basis for Modern Science.” Baker, 1991, p. 30.
123. Jump up ^ Mathpages. “Translating Aristotle”. Accessed July
124. Jump up ^ Gauch 2003, pp. 52–53
125. Jump up ^ George Sampson (1970). The concise Cambridge history of English literature. Cambridge University Press. p.174. ISBN 0-521-09581-6
abcd126. ^ Jump up to: Clegg, Brian. “The First Scientist: A Life of Roger Bacon”. Carroll and Graf Publishers, NY, 2003, p. 2.
127. Jump up ^ Niccolò Leoniceno (1509), De Plinii et aliorum erroribus
liber apud Ferrara, as cited by Sanches, Limbrick & Thomson 1988, p. 13 128. Jump up ^ 'I have sometimes seen a verbose quibbler attempting to
persuade some ignorant person that white was black; to which the latter replied, "I do not understand your reasoning, since I have not studied as much as you have; yet I honestly believe that white differs from black. But pray go on refuting me for just as long as you like." ' – Sanches, Limbrick & Thomson 1988, p. 276
129. Jump up ^ Sanches, Limbrick & Thomson 1988, p. 278.
130. Jump up ^ Bacon, Francis Novum Organum (The New Organon), 1620.
Bacon's work described many of the accepted principles, underscoring the importance of empirical results, data gathering and experiment.
Encyclopaedia Britannica (1911), "Bacon, Francis" states: [In Novum Organum, we ] "proceed to apply what is perhaps the most valuable part of the Baconian method, the process of exclusion or rejection. This elimination of the non-essential, ..., is the most important of Bacon's
contributions to the logic of induction, and that in which, as he
repeatedly says, his method differs from all previous philosophies." 131. Jump up ^ "John Stuart Mill (Stanford Encyclopedia of Philosophy)".
plato.stanford.edu. Retrieved 2009-07-31.
132. Jump up ^ Logik der Forschung, new appendices *XVII–*XIX (not yet
available in the English edition Logic of scientific discovery)
133. Jump up ^ Logic of Scientific discovery, p. 20
134. ^ Jump up to: a b Karl Popper: On the non-existence of scientific
method. Realism and the Aim of Science (1983)
135. Jump up ^ Karl Popper: Science: Conjectures and Refutations.
Conjectures and Refuations, section VII
136. Jump up ^ Karl Popper: On knowledge. In search of a better world,
137. Jump up ^ "The historian ... requires a very broad definition of
"science" – one that ... will help us to understand the modern scientific enterprise. We need to be broad and inclusive, rather than narrow and exclusive ... and we should expect that the farther back we go [in time] the broader we will need to be." – David Pingree (1992), "Hellenophilia versus the History of Science" Isis 83 554–63, as cited on p.3, David C. Lindberg (2007), The beginnings of Western science: the European Scientific tradition in philosophical, religious, and institutional context, Second ed. Chicago: Univ. of Chicago Press ISBN 978-0-226-48205-7
138. Jump up ^ "When we are working intensively, we feel keenly the
progress of our work; we are elated when our progress is rapid, we are depressed when it is slow." – the mathematician Pólya 1957, p. 131 in the section on 'Modern heuristic'.
139. Jump up ^ "Philosophy [i.e., physics] is written in this grand book
– I mean the universe – which stands continually open to our gaze, but it cannot be understood unless one first learns to comprehend the language and interpret the characters in which it is written. It is written in the language of mathematics, and its characters are triangles, circles, and other geometrical figures, without which it is humanly impossible to understand a single word of it; without these, one is wandering around in a dark labyrinth." – Galileo Galilei, Il Saggiatore (The Assayer, 1623), as translated by Stillman Drake (1957), Discoveries and Opinions of Galileo pp. 237–8, as quoted by di Francia 1981, p. 10.
140. Jump up ^ Pólya 1957 2nd ed.
141. Jump up ^ George Pólya (1954), Mathematics and Plausible Reasoning
Volume I: Induction and Analogy in Mathematics,
142. Jump up ^ George Pólya (1954), Mathematics and Plausible Reasoning
Volume II: Patterns of Plausible Reasoning.
143. Jump up ^ Pólya 1957, p. 142
144. Jump up ^ Pólya 1957, p. 144
145. Jump up ^ Mackay 1991 p.100
146. Jump up ^ See the development, by generations of mathematicians,
of Euler's formula for polyhedra as documented by Lakatos, Imre (1976), Proofs and refutations, Cambridge: Cambridge University Press, ISBN 0-521-29038-4
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This article is about a period in the history of science. For the process of scientific progress via revolution, proposed by Thomas Kuhn, see
The scientific revolution was the emergence of modern science during the early modern period, when developments in mathematics, physics, astronomy, biology, medicine, and chemistry transformed views of society and nature. According to traditional accounts, the scientific revolution began in Europe towards the end of the Renaissance era and continued through the late 18th century, influencing the intellectual social movement known as the Enlightenment. While its dates are disputed, the publication in 1543 of Nicolaus Copernicus's De revolutionibus orbium coelestium (On the Revolutions of the Heavenly Spheres) and Andreas Vesalius's De humani corporis fabrica (On the Fabric of the Human body)
is often cited as marking the beginning of the scientific revolution. By the end of the 18th century, the scientific revolution had given way to the "Age of Reflection".
Philosopher and historian Alexandre Koyré coined the term scientific revolution in 1939 to describe this epoch.
? ? ? ? ? ? ? ? ? ? o o 4.2 The chemical philosophy o o 4.4 Mathematization o 8.1 Revolutions
Significance of the revolution
The science of the middle ages was significant in establishing a base for modern science. The Marxist historian and scientist J. D. Bernal asserted that "the renaissance enabled a scientific revolution which let scholars look at the world in a different light. Religion, superstition, and fear were replaced by reason and knowledge". James Hannam says that, while most historians do think something revolutionary happened at this time, "the term 'scientific revolution' is another one of those
prejudicial historical labels that explains nothing. You could call any century from the twelfth to the twentieth a revolution in science" and that the concept "does nothing more than reinforce the error that before Copernicus nothing of any significance to science took place". Despite some challenges to religious views, however, most notable figures of the scientific revolution—including Nicolaus Copernicus, Tycho Brahe, Johannes Kepler, Galileo Galilei, Francis Bacon, René Descartes, Isaac
Newton and Gottfried Leibniz— were devout in their faith. Some scholars see a direct tie between Christian metaphysics and self-sustaining science.
This period saw a fundamental transformation in scientific ideas across mathematics, physics, astronomy, and biology in institutions supporting scientific investigation and in the more widely held picture of the universe. The scientific revolution led to the establishment of several modern sciences. In 1984, Joseph Ben-David wrote:
Rapid accumulation of knowledge, which has characterized the development of science since the 17th century, had never occurred before that time. The new kind of scientific activity emerged only in a few countries of Western Europe, and it was restricted to that small area for about two hundred years. (Since the 19th century, scientific knowledge has been assimilated by the rest of the world).
Many contemporary writers and modern historians claim that there was a revolutionary change in world view. In 1611 the English poet, John Donne, wrote:
[The] new Philosophy calls all in doubt,
The Element of fire is quite put out;
The Sun is lost, and th'earth, and no man's wit
Can well direct him where to look for it.
Mid-20th century historian Herbert Butterfield was less disconcerted, but nevertheless saw the change as fundamental:
Since that revolution turned the authority in English not only of the Middle Ages but of the ancient world—since it started not only in the eclipse of scholastic philosophy but in the destruction of Aristotelian physics—it outshines everything since the rise of Christianity and reduces the Renaissance and Reformation to the rank of mere episodes, mere internal displacements within the system of medieval Christendom.... [It] looms so large as the real origin both of the modern world and of the modern mentality that our customary periodization of European history has become
an anachronism and an encumbrance.
More recently, sociologist and historian of science Steven Shapin opened his book, The Scientific Revolution, with the paradoxical statement: "There was no such thing as the Scientific Revolution, and this is a book about it." Although historians of science continue to debate the exact
meaning of the term, and even its validity, the scientific revolution still remains a useful concept to interpret the many changes in science itself.
Galileo Galilei. Portrait in crayon by Leoni
The scientific revolution was not marked by any single change. The following new ideas contributed to what is called the scientific revolution:
The replacement of the Earth as by heliocentrism.
? Deprecation of the that matter was continuous
and made up of the elements Earth, Water, Air, and Fire because its classic rival, Atomism, better lent itself to a "mechanical
philosophy" of matter.
? The replacement of the Aristotelian idea that heavy bodies, by their
nature, moved straight down toward their natural places; that light bodies, by their nature, moved straight up toward their natural place; and that ethereal bodies, by their nature, moved in
unchanging circular motions with the idea that all bodies are heavy and move according to the same physical laws.
? replaced the medieval , that unnatural motion
("forced" or "violent" rectilinear motion) is caused by continuous ?
action of the original force imparted by a mover into that which is moved.
? The replacement of 's treatment of the venous and arterial
systems as two separate systems with William Harvey's concept that blood circulated from the arteries to the veins "impelled in a circle, and is in a state of ceaseless motion."
However, according to Galileo, the core of what came to be known as the scientific method in modern physical sciences is stated in his book Il Saggiatore to be the concept of a systematic mathematical interpretation of experiments and empirical facts:
"Philosophy [i.e., physics] is written in this grand book—I mean the universe—which stands continually open to our gaze, but it cannot be understood unless one first learns to comprehend the language and
interpret the characters in which it is written. It is written in the language of mathematics, and its characters are triangles, circles, and other geometrical figures, without which it is humanly impossible to understand a single word of it; without these, one is wandering around in a dark labyrinth."
René Descartes with Queen Christina of Sweden.
Many of the important figures of the scientific revolution, however, shared in the Renaissance respect for ancient learning and cited ancient pedigrees for their innovations. Nicolaus Copernicus (1473–1543), Kepler (1571–1630), Newton (1642–1727), and Galileo Galilei
(1564–1642) all traced different ancient and medieval ancestries for the heliocentric system. In the Axioms Scholium of his Principia, Newton said its axiomatic three laws of motion were already accepted by mathematicians such as Huygens (1629–1695), Wallace, Wren, and others, and in memos in his draft preparations of the second edition of the Principia, he attributed its first law of motion and its law of gravity to a range of historical figures. According to Newton himself and other
historians of science, his Principia's first law of motion was the same as Aristotle's counterfactual principle of interminable locomotion in a void stated in Physics 4.8.215a19–22 and was also endorsed by ancient Greek atomists and others. As Newton expressed himself:
All those ancients knew the first law [of motion] who attributed to atoms in an infinite vacuum a motion which was rectilinear, extremely swift and perpetual because of the lack of resistance... Aristotle was of the same mind, since he expresses his opinion thus...[in Physics 4.8.215a19-22], speaking of motion in the void [in which bodies have no gravity and] where there is no impediment he writes: 'Why a body once moved should come to rest anywhere no one can say. For why should it rest here rather than there ? Hence either it will not be moved, or it must be moved indefinitely, unless
something stronger impedes it.'
As Newton attests, the Principia's first law of motion was known in antiquity, even by Aristotle, although its significance, as such, went unappreciated. This refutes Kuhn's thesis of a scientific revolution in dynamics.
The geocentric model was nearly universally accepted until 1543 when Nicolaus Copernicus published his book titled De revolutionibus orbium coelestium and was still widely accepted into the next century. At around the same time, the findings of Vesalius corrected the previous anatomical teachings of Galen, which were based upon the dissection of animals even though they were supposed to be a guide to the human body.
Andreas Vesalius (1514–1564) was an author of one of the most influential
books on human anatomy, De humani corporis fabrica, published in 1543.
French surgeon Ambroise Paré (c.1510–1590) is considered one of the fathers of surgery; he was leader in surgical techniques and battlefield medicine, especially the treatment of wounds. Influenced by the works of Italian surgeon and anatomist Matteo Realdo Colombo (c. 1516–1559), the anatomist William Harvey (1578–1657) described the circulatory system. Herman Boerhaave (1668–1738) is sometimes referred to as a "father of physiology" due to his exemplary teaching in Leiden and his textbook 'Institutiones medicae' (1708).
Antonie van Leeuwenhoek, the first person to use a microscope to view bacteria.
It was between 1650 and 1800 that the science of modern dentistry developed. It is said that the 17th-century French physician Pierre Fauchard
(1678–1761) started dentistry science as we know it today, and he has been named "the father of modern dentistry".
Pierre Vernier (1580–1637) was inventor and eponym of the vernier scale, used in measuring devices. Evangelista Torricelli (1607–1647) was best known for his invention of the barometer. Although Franciscus Vieta (1540–1603) gave the first notation of modern algebra, John Napier (1550–1617) invented logarithms, and Edmund Gunter (1581–1626) created the logarithmic scales (lines, or rules) upon which slide rules are based. It was William Oughtred (1575–1660) who first used two such scales sliding by one another to perform direct multiplication and division, and thus is credited as the inventor of the slide rule in 1622.
Blaise Pascal (1623–1662) invented the mechanical calculator in 1642. The introduction of his Pascaline in 1645 launched the development of mechanical calculators first in Europe and then all over the world. The notion of mathematical probability was first initiated by Pascal with his research in the games of chance; his later theory for binomial coefficient (or Pascal's Triangle) was used as some of the foundation to Leibniz' infinitesimal calculus. He also made important contributions to the study of fluid and clarified the concepts of pressure and vacuum by generalizing the work of Evangelista Torricelli. He wrote a significant treatise on the subject of projective geometry at the age of sixteen and later corresponded with Pierre de Fermat (1601–1665) on probability theory, strongly influencing the development of modern economics and social science.
Gottfried Leibniz (1646–1716), building on Pascal's work, became one of the most prolific inventors in the field of mechanical calculators; he was the first to describe a pinwheel calculator, in 1685, and invented the Leibniz wheel, used in the arithmometer, the first mass-produced mechanical calculator. He also refined the binary number system, foundation of virtually all modern computer architectures. John Hadley (1682–1744) was mathematician inventor of the octant, the precursor to the sextant. Hadley also developed ways to make precision aspheric and parabolic objective mirrors for reflecting telescopes, building the first parabolic Newtonian telescope and a Gregorian telescope with accurately shaped mirrors.
Denis Papin, best known for his pioneering invention of the steam digester, the forerunner of the steam engine. Denis Papin (1647–1712) was best known for his pioneering invention of the steam digester, the forerunner of the steam engine. Abraham Darby I (1678–1717) was the first, and most famous, of three generations of the Darby family who played an important role in the Industrial Revolution. He developed a method of producing high-grade iron in a blast furnace fueled by coke rather than charcoal. This was a major step forward in the production of iron as a raw material for the Industrial Revolution. Thomas Newcomen (1664–1729) perfected a practical steam engine for pumping water, the Newcomen steam engine. Consequently, he can be regarded as a forefather of the Industrial Revolution.
In 1672 Otto von Guericke (1602–1686), was the first human on record to knowingly generate electricity using a machine, and in 1729 Stephen Gray (1666–1736) demonstrated that electricity could be "transmitted"
through metal filaments. The first electrical storage device was invented in 1745, the so-called "Leyden jar," and in 1749 Benjamin Franklin
(1706–1790) demonstrated that lightning was electricity. In 1698 Thomas Savery (c.1650–1715) patented an early steam engine.
German scientist Georg Agricola (1494–1555), known as "the father of mineralogy," published his great work De re metallica. Robert Boyle (1627–1691) was credited with the discovery of Boyle's Law. He is also credited for his landmark publication The Sceptical Chymist, where he attempts to develop an atomic theory of matter. The person celebrated as the "father of modern chemistry" is Antoine Lavoisier (1743–1794) who developed his law of Conservation of mass in 1789, also called Lavoisier's
Law. Antoine Lavoisier proved that burning was caused by oxidation, that is, the mixing of a substance with oxygen. He also proved that diamonds were made of carbon and argued that all living processes were, at their heart, chemical reactions. In 1766 Henry Cavendish (1731–1810)
discovered hydrogen. In 1774 Joseph Priestley (1733–1804) discovered oxygen.
Gottfried Leibniz (1646–1716) refined the binary system, foundation of virtually all modern computer architectures. German physician Leonhart Fuchs (1501–1566) was one of the three founding fathers of botany, along with Otto Brunfels (1489-1534) and Hieronymus Bock (1498–1554) (also called Hieronymus Tragus). Valerius Cordus (1515–1554) authored one of the greatest pharmacopoeias and one of the most celebrated herbals in history, Dispensatorium (1546).
In his Systema Naturae, published in 1767, Carl von Linné (1707–1778) catalogued all the living creatures into a single system that defined
their morphological relations to one another: the Linnean classification system. He is often called the "Father of Taxonomy." Georges Buffon (1707–1788) was perhaps the most important of Charles Darwin's predecessors. From 1744 to 1788, he wrote his monumental Histoire naturelle, générale et particulière, which included everything known about the natural world up until that date.
Along with the inventor and microscopist Robert Hooke (1635–1703), Sir Christopher Wren (1632–1723) and Sir Isaac Newton (1642–1727),
English scientist and astronomer Edmond Halley (1656–1742) was trying to develop a mechanical explanation for planetary motion. Halley's star catalogue of 1678 was the first to contain telescopically determined
locations of southern stars.
Many historians of science have seen other ancient and medieval
antecedents of these ideas. It is widely accepted that Copernicus's De revolutionibus followed the outline and method set by Ptolemy in his Almagest and employed geometrical constructions that had been developed previously by the Maragheh school in his heliocentric model, and that Galileo's mathematical treatment of acceleration and his concept of impetus rejected earlier medieval analyses of motion, rejecting by name; Averroes, Avempace, Jean Buridan, and John Philoponus (see Theory of impetus).
The standard theory of the history of the scientific revolution claims the 17th century was a period of revolutionary scientific changes. It is claimed that not only were there revolutionary theoretical and
experimental developments, but that even more importantly, the way in which scientists worked was radically changed. An alternative
anti-revolutionist view is that science as exemplified by Newton's Principia was anti-mechanist and highly Aristotelian, being specifically directed at the refutation of anti-Aristotelian Cartesian mechanism, as evidenced in the Principia quotations below, and not more empirical than it already was at the beginning of the century or earlier in the works of scientists such as Benedetti, Galileo Galilei, or Johannes Kepler. Ancient and medieval background
Further information: Science in the Middle Ages and Aristotelian Physics The scientific revolution was built upon the foundation of ancient Greek learning and science in the middle ages, as it had been elaborated and further developed by Roman/Byzantine science and medieval Islamic science. The "Aristotelian tradition" was still an important
intellectual framework in by the 17th century, although by that time natural philosophers had moved away from much of it.
Ptolemaic model of the spheres for Venus, Mars, Jupiter, and Saturn. Georg von Peuerbach, Theoricae novae planetarum, 1474.
Key scientific ideas dating back to classical antiquity had changed drastically over the years, and in many cases been discredited. The ideas that remained, which were transformed fundamentally during the scientific revolution, include:
? 's cosmology which placed the Earth at the center of a
spherical hierarchic cosmos. The terrestrial and celestial regions were made up of different elements which had different kinds of natural movement.
o The terrestrial region, according to Aristotle, consisted of
concentric spheres of the four elements—earth, water, air,
and fire. All bodies naturally moved in straight lines until
they reached the sphere appropriate to their elemental
composition—their natural place. All other terrestrial
motions were non-natural, or violent.
o The celestial region was made up of the fifth element, ,
which was unchanging and moved naturally with uniform circular motion. In the Aristotelian tradition,
astronomical theories sought to explain the observed
irregular motion of celestial objects through the combined
effects of multiple uniform circular motions.
? The Ptolemaic model of planetary motion: Based on the geometrical
model of Eudoxus of Cnidus, Ptolemy's Almagest, demonstrated that calculations could compute the exact positions of the Sun, Moon, stars, and planets in the future and in the past, and showed how these computational models were derived from astronomical
observations. As such they formed the model for later astronomical developments. The physical basis for Ptolemaic models invoked
layers of spherical shells, though the most complex models were inconsistent with this physical explanation.
It is important to note that ancient precedent existed for alternative theories and developments which prefigured later discoveries in the area of physics and mechanics; but in light of the limited number of works to survive translation in an era when many books were lost to warfare, such developments remained obscure for centuries and are traditionally held to have had little effect on the re-discovery of such phenomena; whereas the invention of the printing press made the wide dissemination of such incremental advances of knowledge commonplace. Meanwhile, however,
significant progress in geometry, mathematics, and astronomy was made in the medieval era, particularly in the Islamic world as well as Europe. New approaches to nature
Historians of the scientific revolution traditionally maintain that its most important changes were in the way in which scientific investigation was conducted, as well as the philosophy underlying scientific
developments. Among the main changes are the mechanical philosophy, the chemical philosophy, empiricism, and the increasing role of
The mechanical philosophy
For more details on this topic, see mechanical philosophy.
Aristotle recognized four kinds of causes, and where applicable, the most important of them is the "final cause". The final cause was the aim, goal, or purpose of some natural process or man-made thing. Until the scientific revolution, it was very natural to see such aims, such as a child's growth, for example, leading to a mature adult. Intelligence was assumed only in the purpose of man-made artifacts; it was not attributed to other animals or to nature.
In "mechanical philosophy" no field or action at a distance is permitted, particles or corpuscles of matter are fundamentally inert. Motion is caused by direct physical collision. Where natural substances had previously been understood organically, the mechanical philosophers viewed them as machines. As a result, Newton's theory seemed like some kind of throwback to "spooky action at a distance". According to Thomas Kuhn, he and Descartes held the teleological principle that God conserved the amount of motion in the universe:
Gravity, interpreted as an innate attraction between every pair of particles of matter, was an occult quality in the same sense as the scholastics' "tendency to fall" had been.... By the mid eighteenth century that interpretation had been almost universally accepted, and the result was a genuine reversion (which is not the same as a retrogression) to a scholastic standard. Innate attractions and repulsions joined size, shape, position and motion as physically irreducible primary properties of matter.
Newton had also specifically attributed the inherent power of inertia to matter, against the mechanist thesis that matter has no inherent powers. But whereas Newton vehemently denied gravity was an inherent power of matter, his collaborator Roger Cotes made gravity also an inherent power of matter, as set out in his famous preface to the Principia's 1713 second edition which he edited, and contra Newton himself. And it was Cotes's interpretation of gravity rather than Newton's that came to be accepted. (See also Entropic gravity).
Newton in a 1702 portrait by Godfrey Kneller.
The chemical philosophy
Chemistry, and its antecedent alchemy, became an increasingly important aspect of scientific thought in the course of the 16th and 17th centuries. The importance of chemistry is indicated by the range of important
scholars who actively engaged in chemical research. Among them were the astronomer Tycho Brahe, the chemical physician Paracelsus, the Irish philosopher Robert Boyle, and the English philosophers Thomas Browne and Isaac Newton.
Unlike the mechanical philosophy, the chemical philosophy stressed the active powers of matter, which alchemists frequently expressed in terms of vital or active principles—of spirits operating in nature. Empiricism
The Aristotelian scientific tradition's primary mode of interacting with the world was through observation and searching for "natural"
circumstances through reasoning. Coupled with this approach was the belief that rare events which seemed to contradict theoretical models were aberrations, telling nothing about nature as it "naturally" was. During the scientific revolution, changing perceptions about the role of the scientist in respect to nature, the value of evidence, experimental or observed, led towards a scientific methodology in which empiricism played a large, but not absolute, role.
By the start of the scientific revolution, empiricism had already become an important component of science and natural philosophy. Prior thinkers, particularly nominalist William of Ockham in the early 14th century, had begun the intellectual movement toward empiricism. Under the influence of scientists and philosophers like Francis Bacon, a sophisticated
empirical tradition was developed by the 16th century. Belief of natural and artificial circumstances was abandoned, and a research tradition of systematic experimentation was slowly accepted throughout the scientific community. Bacon's philosophy of using an inductive approach to
nature—to abandon assumption and to attempt to simply observe with an open mind—was in strict contrast with the earlier, Aristotelian approach of deduction, by which analysis of known facts produced further
understanding. In practice, of course, many scientists (and philosophers) believed that a healthy mix of both was needed—the willingness to
question assumptions, yet also to interpret observations assumed to have some degree of validity.
At the end of the scientific revolution the organic, qualitative world of book-reading philosophers had been changed into a mechanical,
mathematical world to be known through experimental research. Though it
is certainly not true that Newtonian science was like modern science in all respects, it conceptually resembled ours in many ways. Many of the hallmarks of modern science, especially in respect to the institution and profession of science, did not become standard until the mid-19th century. Mathematization
Scientific knowledge, according to the Aristotelians, was concerned with establishing true and necessary causes of things. To the extent that medieval natural philosophers used mathematical problems, they limited social studies to theoretical analyses of local speed and other aspects
of life. The actual measurement of a physical quantity, and the
comparison of that measurement to a value computed on the basis of theory, was largely limited to the mathematical disciplines of astronomy and optics in Europe.
In the 16th and 17th centuries, European scientists began increasingly applying quantitative measurements to the measurement of physical
phenomena on the Earth. Galileo maintained strongly that mathematics provided a kind of necessary certainty that could be compared to God's: "With regard to those few mathematical propositions which the human intellect does understand, I believe its knowledge equals the Divine in objective certainty."
Key ideas and people that emerged from the 16th and 17th centuries:
? ? First printed edition of in 1482. Nicolaus Copernicus (1473–1543) published the Heavenly Spheres in 1543, which advanced the heliocentric theory of cosmology. (1514–1564) published (On the Fabric of the Human Body) (1543), which discredited Galen's views. He found that the circulation of blood resolved from pumping of the heart. He also assembled the first human skeleton from cutting open cadavers. (1540–1603) published Isagoge (1591), which gave the first symbolic notation of parameters in literal algebra. (1544–1603) published Bodies, and on the Great Magnet the Earth in 1600, which laid the foundations of a theory of magnetism and electricity.
? ? ?
? ? Tycho Brahe (1546–1601) made extensive and more accurate naked eye observations of the planets in the late 16th century. These became the basic data for Kepler's studies. (1561–1626) published in 1620, which outlined a new system of logic based on the process of reduction, which he offered as an improvement over Aristotle's philosophical process of syllogism. This contributed to the development of what became known as the scientific method. (1564–1642) improved the , with which he made several important astronomical discoveries, including the four largest moons of Jupiter, the phases of Venus, and the rings of Saturn, and made detailed observations of sunspots. He developed the laws for falling bodies based on pioneering quantitative experiments which he analyzed mathematically. (1571–1630) published the first two of his three laws of planetary motion in 1609. (1578–1657) demonstrated that blood circulates, using dissections and other experimental techniques. (1596–1650) published his in 1637, which helped to establish the scientific method. Antonie van Leeuwenhoek (1632–1723) constructed powerful single lens microscopes and made extensive observations that he published around 1660, opening up the micro-world of biology. (1643–1727) built upon the work of Kepler and Galileo.
He showed that an inverse square law for gravity explained the elliptical orbits of the planets, and advanced the law of universal gravitation. His development of infinitesimal calculus opened up new applications of the methods of mathematics to science. Newton taught that scientific theory should be coupled with rigorous experimentation, which became the keystone of modern science. Theoretical developments
Portrait of Johannes Kepler.
In 1543 Copernicus' work on the heliocentric model of the solar system was published, in which he tried to demonstrate that the sun was the center of the universe. Few were bothered by this suggestion, and the pope and several archbishops were interested enough by it to want more detail. His model was later used to create the calendar of Pope Gregory XIII. For almost two millennia, the geocentric model had been accepted by all but a few astronomers. The idea that the earth moved around the sun, as advocated by Copernicus, was to most of his contemporaries doubtful. It contradicted not only empirical observation, due to the absence of an observable stellar parallax, but also Aristotelian philosophy.
The discoveries of Johannes Kepler and Galileo gave the theory credibility. Kepler was an astronomer who, using the accurate observations of Tycho Brahe, proposed that the planets move around the sun not in circular orbits, but in elliptical ones. Together with his other laws of planetary motion, this allowed him to create a model of the solar system that was an improvement over Copernicus' original system. Galileo's main
contributions to the acceptance of the heliocentric system were his mechanics, the observations he made with his telescope, as well as his detailed presentation of the case for the system. Using an early theory of inertia, Galileo could explain why rocks dropped from a tower fall straight down even if the earth rotates. His observations of the moons of Jupiter, the phases of Venus, the spots on the sun, and mountains on the moon all helped to discredit the Aristotelian philosophy and the Ptolemaic theory of the solar system. Through their combined discoveries, the heliocentric system gained support, and at the end of the 17th century it was generally accepted by astronomers.
Kepler's laws of planetary motion and Galileo's mechanics culminated in the work of Isaac Newton. His laws of motion were to be the solid foundation of mechanics; his law of universal gravitation combined terrestrial and celestial mechanics into one great system that seemed to be able to describe the whole world in mathematical formulae.
Not only astronomy and mechanics were greatly changed. Optics, for instance, was revolutionized by people like Robert Hooke, Christiaan Huygens, René Descartes and, once again, Isaac Newton, who developed mathematical theories of light as either waves (Huygens) or particles (Newton). Similar developments could be seen in chemistry, biology and other sciences, although their full development into modern science was delayed for a century or more.
See also: Historical revisionism
Matteo Ricci (left) and Xu Guangqi (right) in Athanasius Kircher, La Chine ... Illustrée, Amsterdam, 1670.
Not all historians of science are agreed that there was any revolution in the 16th or 17th century. The continuity thesis is the hypothesis that there was no radical discontinuity between the intellectual development of the Middle Ages and the developments in the Renaissance and early modern period. Thus the idea of an intellectual or scientific revolution
following the Renaissance is—according to the continuity thesis—a myth. Some continuity theorists point to earlier intellectual revolutions
occurring in the Middle Ages, usually referring to either a European "Renaissance of the 12th century" or a medieval "Muslim scientific revolution", as a sign of continuity.
Another contrary view has been recently proposed by Arun Bala in his dialogical history of the birth of modern science. Bala argues that the changes involved in the Scientific Revolution—the mathematical realist turn, the mechanical philosophy, the atomism, the central role assigned to the Sun in Copernican heliocentrism—have to be seen as rooted in multicultural influences on Europe. Islamic science gave the first
exemplar of a mathematical realist theory with Alhazen's Book of Optics in which physical light rays traveled along mathematical straight lines and also laid the foundation of the inductive scientific method. The swift transfer of Chinese mechanical technologies in the medieval era shifted European sensibilities to perceive the world in the image of a machine and their impact fueled an desire for more mechanical inventions. The Hindu-Arabic numeral system, which developed in close association with atomism in India, carried implicitly a new mode of mathematical atomic thinking. And the heliocentric theory, which assigned central status to the Sun, as well as Newton's concept of force acting at a distance, were rooted in ancient Egyptian religious ideas associated with Hermeticism. Bala argues that by ignoring such multicultural impacts we have been led to a Eurocentric conception of the scientific revolution.
However Arun Bala clearly states: "The makers of the revolution –
Copernicus, Kepler, Galileo, Descartes, Newton, and many others – had to selectively appropriate relevant ideas, transform them, and create new auxiliary concepts in order to complete their task... In the ultimate analysis, even if the revolution was rooted upon a multicultural base it is the accomplishment of Europeans in Europe."
A third approach takes the term "renaissance" literally. A closer study of Greek Philosophy and Greek Mathematics demonstrates that nearly all of the so-called revolutionary results of the so-called scientific
revolution were in actuality restatements of ideas that were in many cases older than those of Aristotle and in nearly all cases at least as old as Archimedes. Aristotle even explicitly argues against some of the ideas that were demonstrated during the scientific revolution, such as heliocentrism. The basic ideas of the scientific method were well known to Archimedes and his contemporaries, as demonstrated in the well known discovery of buoyancy. Atomism was first thought of by Leucippus and Democritus. This view of the scientific revolution reduces it to a period of relearning classical ideas that is very much an extension of the renaissance, specifically relearning ideas that originated with somebody other than Aristotle and particularly those rooted in the schools of Plato
and Pythagoras. This view of the scientific revolution does not deny that a change occurred but argues that it was a reassertion of previous
knowledge (a renaissance) and not the creation of new knowledge. It cites statements from Newton, Copernicus and others in favour of the Pythagorean
worldview as evidence.