THEORY

hypothesis, possibility, theory

(noun) a tentative insight into the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena; “a scientific hypothesis that survives experimental testing becomes a scientific theory”; “he proposed a fresh theory of alkalis that later was accepted in chemical practices”

theory

(noun) a belief that can guide behavior; “the architect has a theory that more is less”; “they killed him on the theory that dead men tell no tales”

theory

(noun) a well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena; “theories can incorporate facts and laws and tested hypotheses”; “true in fact and theory”

Source: WordNet® 3.1

---

Etymology

Noun

theory (countable and uncountable, plural theories)

A description of an event or system that is considered to be accurate.

(obsolete) Mental conception; reflection, consideration. [16th-18th c.]

(sciences) A coherent statement or set of ideas that explains observed facts or phenomena and correctly predicts new facts or phenomena not previously observed, or which sets out the laws and principles of something known or observed; a hypothesis confirmed by observation, experiment etc. [from 17th c.]

(uncountable) The underlying principles or methods of a given technical skill, art etc, as opposed to its practice. [from 17th c.]

(mathematics) A field of study attempting to exhaustively describe a particular class of constructs. [from 18th c.]

A hypothesis or conjecture. [from 18th c.]

(countable, logic) A set of axioms together with all statements derivable from them; or, a set of statements which are deductively closed. Equivalently, a formal language plus a set of axioms (from which can then be derived theorems). The statements may be required to all be bound (i.e., to have no free variables).

Usage notes

In scientific discourse, the sense “unproven conjecture” is discouraged (with hypothesis or conjecture preferred), due to unintentional ambiguity and intentional equivocation with the sense “well-developed statement or structure”.

Synonyms

• See also supposition

Hyponyms

• acoustic theory

• algorithmic information theory

• antenna theory

• atomic theory

• catastrophe theory

• category theory

• cell theory

• chaos theory

• circuit theory

• complexity theory

• computation theory

• control theory

• critical theory

• decision theory

• domino theory

• extreme value theory

• game theory

• giant impact theory

• graph theory

• group theory

• information theory

• kinetic theory of gases

• knot theory

• literary theory

• M-theory

• music theory

• number theory

• opponent-process theory

• phlogiston theory

• probability theory

• proof theory

• quantum field theory

• rational choice theory

• set theory

• signal theory

• social theory

• spectral theory

• systems theory

• theory of gravity

• theory of relativity

• theory of truth

• Theory X

• Theory Y

• type theory

• value theory

• virtue theory

Meronyms

• (in logic): axioms

Holonyms

• (in logic): formal system

Anagrams

• Yother, thyreo-

Source: Wiktionary

---

The"o*ry, n.; pl. Theories. Etym: [F. théorie, L. theoria, Gr. Theater.]

1. A doctrine, or scheme of things, which terminates in speculation or contemplation, without a view to practice; hypothesis; speculation.

Note: "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.

2. An exposition of the general or abstract principles of any science; as, the theory of music.

3. The science, as distinguished from the art; as, the theory and practice of medicine.

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. See under Atomic, Binary, etc.

Syn.

– Hypothesis, speculation.

– Theory, Hypothesis. 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.

Source: Webster’s Unabridged Dictionary 1913 Edition

---