Philosophy of science

The philosophy of science is the branch of philosophy which studies the philosophical foundations, assumptions, and implications of science, including the natural sciences such as physics and biology, and the social sciences, such as psychology and economics. In this respect, the philosophy of science is closely related to epistemology and ontology. It seeks to explain such things as: the nature of scientific statements and concepts; the way in which they are produced; how science explains, predicts and, through technology, harnesses nature; the means for determining the validity of information; the formulation and use of the scientific method; the types of reasoning used to arrive at conclusions; and the implications of scientific methods and models for the larger society, and for the sciences themselves.

The justification of scientific statements

The most powerful statements in science are those with the widest applicability. Newton's Third Law — "for every action there is an opposite and equal reaction" — is a powerful statement because it applies to every action, anywhere, and at any time.

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But it is not possible for scientists to have tested every incidence of an action, and found a reaction. How is it, then, that they can assert that the Third Law is in some sense true? They have, of course, tested many, many actions, and in each one have been able to find the corresponding reaction. But can we be sure that the next time we test the Third Law, it will be found to hold true?

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Induction

One solution to this problem is to rely on the notion of induction. Inductive reasoning maintains that if a situation holds in all observed cases, then the situation holds in all cases. So, after completing a series of experiments that support the Third Law, one is justified in maintaining that the Law holds in all cases.

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Explaining why induction commonly works has been somewhat problematic. One cannot use deduction, the usual process of moving logically from premise to conclusion, because there is simply no syllogism that will allow such a move. No matter how many times 17th Century biologists observed white swans, and in how many different locations, there is no deductive path that can lead them to the conclusion that all swans are white. This is just as well, since, as it turned out, that conclusion would have been wrong. Similarly, it is at least possible that an observation will be done tomorrow that shows an occasion in which an action is not accompanied by a reaction; the same is true of any scientific law.

Related Topics:
Deduction - Swans

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One answer has been to conceive of a different form of rational argument, one that does not rely on deduction. Deduction allows one to formulate a specific truth from a general truth: all crows are black; this is a crow; therefore this is black. Induction somehow allows one to formulate a general truth from some series of specific observations: this is a crow and it is black; that is a crow and it is black; therefore all crows are black.

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The problem of induction is one of considerable debate and importance in the philosophy of science: is induction indeed justified, and if so, how?

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Falsifiability

: Main article: Falsifiability

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Another way to distinguish science from pseudoscience (e.g. astronomy from astrology), first formally discussed by Karl Popper in 1919-20 and reformulated by him in the 1960s, is falsifiability. This principle states that in order to be useful (or even scientific at all), a scientific statement ('fact', theory, 'law', principle, etc) must be falsifiable, i.e. able to be tested and proven wrong.

Related Topics:
Science - Pseudoscience - Astronomy - Astrology - Karl Popper - 1960s - Falsifiability

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Popper described falsifiability using the following observations, paraphrased from a 1963 essay on "Conjectures and Refutations":

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• It is easy to confirm or verify nearly every theory ? if we look for confirmations.
• Confirmations are significant only if they are the result of risky predictions; that is, if, unenlightened by the theory, we should have expected an event which was incompatible with the theory ? an event which would have refuted the theory.
• "Good" scientific theories include prohibitions which forbid certain things to happen. The more a theory forbids, the better it is.
• A theory which is not refutable by any conceivable event is non-scientific. Irrefutability is not a virtue of a theory.
• Every genuine test of a theory is an attempt to falsify or refute it. Theories that take greater "risks" are more testable, more exposed to refutation.
• Confirming or corroborating evidence is only significant when it is the result of a genuine test of the theory; "genuine" in this case means that it comes out of a serious but unsuccessful attempt to falsify the theory.
• Some genuinely testable theories, when found to be false, are still upheld by their advocates ? for example by introducing ad hoc some auxiliary assumption, or by reinterpreting the theory ad hoc in such a way that it escapes refutation. Such a procedure is always possible, but it rescues the theory from refutation only at the price of destroying, or at least lowering, its scientific status.

These observations are part of Popper's case for defending the idea that what makes a theory scientific is its falsifiability, or refutability, or testability.

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Coherentism

Induction and Falsification both attempt to justify scientific statements by reference to other specific scientific statements. Both must avoid the problem of the criterion, in which any justification must in turn be justified, resulting in an infinite regress. The regress argument has been used to justify one way out of the infinite regress, foundationalism. Foundationalism claims that there are some basic statements that do not require justification. Both induction and falsification are forms of foundationalism in that they rely on basic statements that derive directly from observations.

Related Topics:
Problem of the criterion - Regress argument - Foundationalism

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The way in which basic statements are derived from observation complicates the problem. Observation is a cognitive act; that is, it relies on our existing understanding, our set of beliefs. An observation of a transit of Venus requires a huge range of auxiliary beliefs, such as those that describe the optics of telescopes, the mechanics of the telescope mount, and an understanding of celestial mechanics. At first sight, the observation does not appear to be 'basic'.

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Coherentism offers an alternative by claiming that statements can be justified by their being a part of a coherent system. In the case of science, the system is usually taken to be the complete set of beliefs of an individual or of the community of scientists. W. V. Quine argued for a Coherentist approach to science. An observation of a transit of Venus is justified by its being coherent with our beliefs about optics, telescope mounts and celestial mechanics. Where this observation is at odds with one of these auxiliary beliefs, an adjustment in the system will be required to remove the contradiction.

Related Topics:
Coherentism - W. V. Quine

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Occam's Razor

Occam's Razor is used to justify some scientific claims. William of Occam is attributed with suggesting that the simplest account which 'explains' the phenomenon is to be preferred. Occam's razor is often phrased as "entities should not be multiplied beyond necessity."

Related Topics:
Occam's Razor - William of Occam - Explains

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Consider the ubiquitous situation of two theories A and B, where A is the most basic version of the theory that fits the data, and B is a version of A augmented with additional elements which neither improve nor harm the fit. The principle of Occam's Razor advises us to "shave" away the additional elements of B leaving us with the more basic version A.

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Because for any theory there are an infinite number of variations which are equally consistent with the current data, Occam's razor is used implicitly in every instance of scientific research. As an example, consider Newton's famous theory that "for every action there is an equal and opposite reaction." An alternative theory would be that "for every action there is an equal and opposite reaction, except on the 12 of January 2055 when the reaction will be of half intensity." This seemingly absurd addition violates the Occam's Razor principle because it is a gratuitous addition. Indeed without a rule like Occam's Razor there would never be any philosophical or practical justification for scientists to advance any theory over its infinite competitors, and science would have no predictive power at all.

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A difficulty with Occam's razor is that it does not specify, nor is it always obvious, which theory is the simpler. Also, Occam's Razor expresses nothing more than an aesthetic preference for simplicity. It is therefore difficult to give the notion rigour. There are related mathematical approaches from Bayesian analysis and information theory that seek to quantify simplicity. One such is minimum message length inference.

Related Topics:
Bayesian analysis - Information theory - Minimum message length

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Occam's Razor does not say that the simplest account is to be preferred regardless of its capacity to explain outliers, exceptions, or other phenomena in question. The principle of falsifiability requires that any exception that can be reliably reproduced should invalidate the simplest theory, and that the next-simplest account which can actually incorporate the exception as part of the theory should then be preferred to the first. As Albert Einstein puts it, "The supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience."

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