hypothesis

hypothesis, theory, law are often interchangeable in general use. In their technical senses they are usually discriminated by the scientists and philosophers who employ them. In general the terms denote an inference from data that is offered as a formula to explain the abstract and general principle that lies behind the data and determines their cause, their method of operation, or their relation to other phenomena.

In such usage hypothesis implies tentativeness in the reference because of insufficient evidence and applies to a well-founded conjecture that serves as a point of departure for scientific discussion or as a tentative guide for further investigation or as the most reasonable explanation of an imperfectly comprehended phenomenon

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a scientist says in effect—"Observation shows that the following facts are true; I find that a certain hypothesis as to their origin is consistent with them all"— Jeans

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the resemblance to electric polarization is very close; it is in fact so close that it would not be foolish at all to make the hypothesis that the iron contains not only electrons but also tiny corpuscles of some subtle magnetic fluid— Darrow

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in the last chapter I proposed the hypothesis that a pure poetry exists, employing the term "lyric" to describe poems which "consist of poetry and nothing else"—Day Lewis

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Theory, in general use, often means little more than hypothesis or conjecture

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"Let us sit quiet, and hear the echoes about which you have your theory." "Not a theory, it was a fancy"— Dickens

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in the course of my work in Egypt, I had formulated certain theories of my own about plague, and could not reconcile them to the findings of the Commission— Heiser

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but in precise technical use it presupposes more supporting evidence than hypothesis does, a wider range of application, and greater likelihood of truth. It is not always obvious when hypothesis and when theory should be used; in comparable applications hypothesis is preferred by some scientists as the more modest in its claims, theory being preferred by others as suggesting such confidence in the reliability of the inference and its supporting evidence as to imply that it deserves acceptance

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the Darwinian explanation of the origin of species is regarded by some as a hypothesis, but is more often designated as the theory of evolution

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that exact verbal expression of as much as we know of the facts, and no more, which constitutes a perfect scientific theory— T. H. Huxley

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in 1905 Einstein crystallized these concepts and hypotheses in his theory of light quanta, according to which all radiation consisted of discrete bullet-like units— Jeans

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there was also a nascent theory of sound waves; and out of it there grew ... a tremendous mathematical doctrine of waves which nowadays has almost come to dominate the physics of these times— Darrow

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Law (for fuller treatment see PRINCIPLE) emphasizes certainty and proof and therefore applies to a statement of an order or relation in phenomena that has been found to be invariable under the same conditions

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in philology, Grimm's law is a statement of the regular changes which the stops, or mute consonants, of the primitive IndoEuropean consonant system have undergone in the Germanic languages

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However, since such laws are subject to correction or alteration by the discovery of contradictory or additional evidence, the term is often changed in the course of time to theory, thus, what has long been known as Newton's law of gravitation is currently being revised as a result of Einstein's discoveries and is sometimes designated as Newton's mathematical theory of universal gravitation.

Analogous words: conjecture, surmise, guess (see under CONJECTURE vb): inference, deduction, conclusion (see under INFER)