Chris Peterson wrote:Sputnick wrote:By the way .. the 'Big Bang' is a theory, an idea, a possibility but not a likelihood and it bothers me the way it is thrown around as if fact.
Everything we know about the Universe is theory. The Big Bang happens to be so well supported, by so many independent lines of evidence, that it almost falls into the "fact" category (something like the theory that the Sun will rise in the east tomorrow). It most certainly is the likelihood, not a mere possibility.
Outside a discussion specifically centered on the origin of the Universe, you will, indeed, find the Big Bang accepted largely as fact. Almost no cosmologists doubt the existence of the Big Bang; where the discussions get heated is in the finer details.
Webster's Revised Unabridged Dictionary (1913)
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Theory, n.; pl. Theories (#). [F. théorie, L. theoria, Gr. a beholding, spectacle, contemplation, speculation, fr. a spectator, to see, view. See Theater.]
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1. A doctrine, or scheme of things, which terminates in speculation or contemplation, without a view to practice; hypothesis; speculation. &hand; This word is employed by English writers in a very loose and improper sense. It is with them usually convertible into hypothesis, and hypothesis is commonly used as another term for conjecture. The terms theory and theoretical are properly used in opposition to the terms practice and practical. In this sense, they were exclusively employed by the ancients; and in this sense, they are almost exclusively employed by the Continental philosophers." Sir W. Hamilton.
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2. An exposition of the general or abstract principles of any science; as, the theory of music.
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3. The science, as distinguished from the art; as, the theory and practice of medicine.
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4. The philosophical explanation of phenomena, either physical or moral; as, Lavoisier's theory of combustion; Adam Smith's theory of moral sentiments. Atomic theory, Binary theory, etc. A theory is a scheme of the relations subsisting between the parts of a systematic whole; an hypothesis is a tentative conjecture respecting a cause of phenomena.
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Hypothesis, n.; pl. Hypotheses (#). [NL., fr. Gr. foundation, supposition, fr. to place under, under + to put. See Hypo-, Thesis.]
1. A supposition; a proposition or principle which is supposed or taken for granted, in order to draw a conclusion or inference for proof of the point in question; something not proved, but assumed for the purpose of argument, or to account for a fact or an occurrence; as, the hypothesis that head winds detain an overdue steamer.
An hypothesis being a mere supposition, there are no other limits to hypotheses than those of the human imagination. J. S. Mill.
2. (Natural Science) A tentative theory or supposition provisionally adopted to explain certain facts, and to guide in the investigation of others; hence, frequently called a working hypothesis. Syn. -- Supposition; assumption.
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Nebular hypothesis: an hypothesis to explain the process of formation of the stars and planets, presented in various forms by Kant, Herschel, Laplace, and others. As formed by Laplace, it supposed the matter of the solar system to have existed originally in the form of a vast, diffused, revolving nebula, which, gradually cooling and contracting, threw off, in obedience to mechanical and physical laws, succesive rings of matter, from which subsequently, by the same laws, were produced the several planets, satellites, and other bodies of the system. The phrase may indicate any hypothesis according to which the stars or the bodies of the solar system have been evolved from a widely diffused nebulous form of matter.