Scientific method: Difference between revisions

"The Scientific Method" usually refers to a series of processes that is supposed to characterize scientific investigation and the furthering of knowledge about the world. It was first enunciated by Roger Bacon in the thirteenth century as a repeating cycle of observation, hypothesis, experimentation and the need for independent verification. It spurns the use of unfounded speculation and analogical arguments.

Public school students are generally taught a mechanical algorithm that is presented as "the scientific method"; they are often taught that this is how all scientists operate all of the time. In contrast, working scientists generally deny that that there is any one method that all scientists always follow like an algorithm. Instead, scientists use the term scientific method to loosely describe the series of steps stated below, which allows creativity and inspiration to enter at any point in the process.

Historians, philosophers and sociologists regard the algorithmic and mechanical model of the scientific method as naive; some hold that no form of scientific method exists, although this position is controversial and rejected by the great majority of working scientists.

In fact, many see the course of scientific progress as inseparable from the politics and culture of science, and for them scientific method at least partly encompasses these influences. All scholars would agree that scientific progress cannot be either explained or prescribed as a single, formularizable process.

The question of how science operates is important to the wider community. In the judicial system and in policy debates, for example, a study's deviation from accepted scientific practice is grounds to reject it as "junk science." Science represents a standard of proficiency and reliability, and this is due at least in part to the way scientists work.

The scientific method in theory

The idealized description of how scientists work is traditionally described as follows:

Observe: Observe or read about a phenomenon.
Hypothesize: Wonder about your observations, and invent a hypothesis, a 'guess', which could explain the phenomenon or set of facts that you have observed.
Test
- Predict: Use the logical consequences of your hypothesis to predict observations of new phenomena or results of new measurements.
- Experiment: Perform experiments to test these predictions, to find just which prediction occurred.
Conclude: Accept or refute hypothesis
- Evaluate: Search for other possible explanations of the result until you can show that your guess was indeed the explanation, with confidence.
- Formulate new hypothesis

Few people believe that there is any one method that all scientists follow like an algorithm. However, many people believe that the idealized scientific method captures the essence of how science operates. The elements of this method are described in more detail below.

Observation

The scientific method begins with observation. Observation often demands careful measurements.

Scientists use operational definitions of their measurements; measurements are defined in terms of physical actions that can be performed by anyone, rather than being defined in terms of abstract ideas or common understanding.

For example, the term "day" is useful in ordinary life and we don't have to define it precisely to make use of it. But in studying the motion of the Earth, you have to define the words you use very precisely; for example, science makes two distinct operational definitions of a day: a solar day is the time between observing the sun at a particular position in the sky and observing it in the same position the next time; a sidereal day is the time between observing a specific star in the night sky at a specific position, and that same observation made the next time.

The slight differences between different operational definitions are often important, as they are needed to make experiments precise enough to reveal underlying physical phenomena that may be too subtle to detect otherwise. Distinctions in operation definitions can also be important conceptual differences: for example, mass and weight are regarded as quite different concepts in science.

Hypothesis

To explain the observation, scientists use whatever they can (their own creativity (currently not well understood), ideas from other fields, or even systematic guessing, or any other methods available) to come up with possible explanations for the phenomenon under study. The most important aspect of an explanation (ie, an hypothesis) is that it must be falsifiable, that is, capable of being demonstrated wrong.

The scientist should also be -- but need not be and often is not -- impartial, considering all known evidence, and not merely evidence which supports the hypothesis under development. This makes it more likely that the hypotheses formed will be relevant and useful and not subject to external bias and distortion.

In the extremely rare cases where no better grounds for discriminating between rival hypotheses can be found, the bias scientists almost always follow is the principle of Occam's Razor; one chooses the simplest explanation for all the available evidence.

Prediction

A hypotheses must make specific predictions; these predictions can be tested with concrete measurements to support or refute the hypothesis. For instance, Albert Einstein's General Relativity makes many specific predictions about the structure of space-time, such as the prediction that light bends in a strong gravitational field, and the amount of bending depends in a precise way on the strength of the gravitational field. Observations made of a 1919 solar eclipse supported the hypothesis (ie, General Relativity) as against all other possible hypotheses which did not make such a prediction. (Later experiments confirmed this even further.)

Deductive reasoning is generally used to develop predictions used to test a hypothesis.

Verification

Probably the most important aspect of scientific reasoning is verification: The results of one's experiments must be verified.

This is both useful as a practical matter (e.g., in chemical engineering or planetary exploration), but have sometimes demonstrated previously unknown variations from currently accepted theory (e.g., the CPT experiments of Yang and Lee in the 1950s which forced fundamental changes in much of particle physics). Ideally, the experiments performed should be fully described so that anyone can reproduce them, and many scientists should independently verify every hypothesis. Results which can be obtained from experiments performed by multiple scientists are termed reproducible and are given much greater weight in evaluating hypotheses than non reproducible results.

Scientists must design their experiments carefully. For example, if the measurements are difficult to make, or subject to observer bias, one must be careful to avoid distorting the results by the experimenter's wishes. When experimenting on complex systems, one must be careful to isolate the effect being tested from other possible causes of the intended effect (this results in a controlled experiment). In testing a drug, for example, it is important to carefully test that the supposed effect of the drug is produced only by the drug itself, and not by the placebo effect or by random chance. Doctors do this with what is called a double-blind study: two groups of patients are compared, one of which receives the drug and one of which receives a placebo. No patient in either group knows whether or not they are getting the real drug; even the doctors or other personnel who interact with the patients don't know which patient is getting the drug under test and which is getting a fake drug (often sugar pills), so their knowledge can't influence the patients either.

Evaluation

Any hypothesis, no matter how respected or time-honored, must be discarded once it is contradicted by new reliable evidence. Hence all scientific knowledge is always in a state of flux, for at any time new evidence could be presented that contradicts long-held hypotheses. A classic example is the explanation of light. Isaac Newton's particle paradigm was overturned by the wave theory of light, which explained diffraction, and which was held to be incontrovertible for many decades.The wave paradigm, in turn was refuted by the discovery of the photoelectric effect. The currently held theory of light holds that photons (the 'particles' of light) are both waves and particles; experiments have been performed which demonstrate that light has both particle and wave properties.

The experiments that reject a hypothesis should be performed by many different scientists to guard against bias, mistake, misunderstanding, and fraud. Scientific journals use a process of peer review, in which scientists submit their results to a panel of fellow scientists (who may or may not know the identity of the writer) for evaluation. Scientists are rightly suspicious of results that do not go through this process; for example, the cold fusion experiments of Fleischmann and Pons were never peer reviewed -- they were announced directly to the press, before any other scientists had tried to reproduce the results or evaluate their efforts. They have not been reproduced elsewhere as yet; and the press announcement was regarded, by most nuclear physicists, as very likely wrong. Proper peer review would have, most likely, turned up problems and led to a closer examination of the experimental evidence Fleischmann, Pons, et al believed they had. Much embarrassment, and wasted effort worldwide, would have been avoided.

The scientific method in practice

Most philosophers of science are agreed that there are no definitive guidelines for the production of new hypotheses. The history of science is filled with stories of scientists describing a "flash of inspiration", or a hunch, which then motivated them to look for evidence to support or refute their idea. The anecdote that an apple falling on Isaac Newton's head inspired his theory of gravity is a popular example of this (there is no evidence that the apple fell on his head; all Newton said was that his ideas were inspired "by the fall of an apple.") Kekule's account of the inspiration for his hypothesis of the structure of the benzene-ring (dreaming of snakes biting their own tails) is better attested.

Scientists tend to look for theories that are "elegant" or "beautiful"; in contrast to the usual English use of these terms, scientists have a more specific meaning in mind. "Elegance" (or "beauty") refers to the ability of a theory to neatly explain all known facts as simply as possible, or in a manner consistent with Occam's Razor.

History is replete with examples of accurate theories ignored by peers, and inaccurate ones propagated unduly, due to social factors. An example is the development of astronomical theory that began, more or less, with the Aristotelian model of the universe: "The earth is the center of a pristine, perfect universe," and all motions in such a universe must be circular. The Aristotelian model was afflicted with various anomalies, such as the apparent retrograde motion of the planets, which were accommodated by modifications of the model. Nicolaus Copernicus's model differed by placing the sun at the center of planetary motion. Both Kepler and Galileo found evidence that supported the heliocentric model. Aristotle's laws were replaced by Isaac Newton, and eventually by Albert Einstein's General Relativity. This example demonstrates that much time may pass before a substitute paradigm is widely accepted. The Aristotelian model dominated Western thought for more than 2000 years before Newton's viewpoint took its place.

Late 20th century study on the scientific method has focused on quasi-empirical methods, such as peer review, the spread of notations, which are the key common concern of philosophy of science, and the philosophy of mathematics.

External links

An Introduction to Science: Scientific Thinking and the Scientific Method by Steven D. Schafersman.
[1] Introduction to the Scientific Method
The Myth of the Scientific Method by Dr. Terry Halwes
Rational Reconstruction and Historical Reconstruction, Horus Publications

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 "'''The Scientific Method'''" usually refers to a series of processes that is supposed to characterize scientific investigation and the furthering of [[knowledge]] about the world.  It was first enunciated by [[Roger Bacon]] in the thirteenth century as a repeating cycle of observation, hypothesis, experimentation and the need for independent verification.  It spurns the use of unfounded speculation and analogical arguments.
-Public school students are generally taught a mechanical algorithm that is presented as "the scientific method"; they are often taught that this is how all scientists operate all of the time. In contrast, working scientists generally deny that that there is any one method that all scientists always follow like an algorithm. Instead, scientists use the term ''scientific method'' to loosely describe the series of steps stated below, which allows creativity and inspiration are allowed to enter at any point in the process.
+Public school students are generally taught a mechanical algorithm that is presented as "the scientific method"; they are often taught that this is how all scientists operate all of the time. In contrast, working scientists generally deny that that there is any one method that all scientists always follow like an algorithm. Instead, scientists use the term ''scientific method'' to loosely describe the series of steps stated below, which allows creativity and inspiration to enter at any point in the process.
 [[history of science|Historians]], [[philosophy of science|philosophers]] and [[sociology of knowledge|sociologists]] regard the algorithmic and mechanical model of the scientific method as naive; some hold that no form of scientific method exists, although this position is controversial and rejected by the great majority of working scientists.

Langbahn Team – Weltmeisterschaft