theology = T = thinko

theory n.

The consensus, idea, plan, story, or set of rules that is currently being used to inform a behavior. This usage is a generalization and (deliberate) abuse of the technical meaning. "What's the theory on fixing this TECO loss?" "What's the theory on dinner tonight?" ("Chinatown, I guess.") "What's the current theory on letting lusers on during the day?" "The theory behind this change is to fix the following well-known screw...."

--Jargon File, autonoded by rescdsk.

In science, an explanation for observational data. A good scientific theory explains as much of the data as possible (a perfect theory would explain all of it), is as elegant as possible, and requires as few miracles as possible. A bad scientific theory conflicts with the data, is less elegant than another theory attempting to explain the same data, or requires miracles.

In philosophy, a set of propositions and their closure under logical implication, used to present a view about some philosophical issue. A good philosophical theory is consistent, is elegant and requires few miracles, but ordinarily does not need to explain any observational data. (Sometimes, however, philosophical theories are constructed in order to explain certain intuitions people have about notions such as free will, meaning, or the world before they begin to think in philosophical terms.) A bad philosophical theory often is inconsistent, requires an inelegant ontology or is question-begging.

As used by scientists, including those who study evolution, a theory is an empirically verifiable proposition that seeks to explain some portion of reality.

Much of the requirements of theories come from the work of Karl Popper. The first requirement is that a theory be expressed in a way that can be tested. In other words, the theory must be falsifiable using data obtained during some form of observation. Theories should be expressed in the simplest possible terms. Theories that are not falsified may evolve as they are refined. According to Popper, a theory may be considered improved only when the new addition explains more than the flaw or flaws it was intended to address. This is the requirement for parsimony, and is intended to prevent theories from becoming nothing more than a series of patches, like the epicycles in Copernicus and Ptolemy's theories of cosmology, which were finally overturned by Kepler.

The common use of the word theory reduces the term to nothing more than an organized guess. But nothing can rise to the level of theory without presenting a falsifiable proposition. In fact, before a hypothesis may be considered theory, it must have already survived a series of independent experiments. In science theory is a very strong word, quite different from the common usage.

The"o*ry (?), n.; pl. Theories (#). [F. th'eorie, L. theoria, Gr. θεωρια a beholding, spectacle, contemplation, speculation, fr. a spectator, to see, view. See Theater.]


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

⇒ "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.


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


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


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.


© Webster 1913.

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