Traditionally, the three fundamental laws of logic: (1) the law of contradiction, (2) the law of excluded middle (or third), and (3) the principle of identity. That is, (1) for all propositions p, it is impossible for both p and not p to be true (symbolically, ¬(p ∧ ¬p)); (2) either p or not p must be true, there being no third or middle true proposition between them (symbolically p ∨ ¬p); and (3) if a propositional function F is true of an individual variable x, then F is true of x (symbolically, (∀x) [F(x) ⊃ F(x)]). Another formulation of the principle of identity asserts that a thing is identical with itself, or (∀x) (x = x).
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Action of using one's mind to produce thoughts, or covert symbolic responses to stimuli. Theories of thought and thought processes have concentrated largely on directed thinking, including problem solving. At the beginning of the 20th century, researchers focused on studying mental associations. Theorists of Gestalt psychology in the 1920s and '30s believed the elements of thought to be in the nature of patterns elicited from experience. Today these elements are often regarded as bits of information undergoing processing. Seealso cognitive psychology, information processing.
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Mind-healing movement that originated in the U.S. in the 19th century. Its earliest proponent, Phineas P. Quimby (1802–66), was a mesmerist who taught that illness is mental. New Thought was influenced by philosophers ranging from Plato to Emanuel Swedenborg, Georg Wilhelm Friedrich Hegel, and Ralph Waldo Emerson and in turn influenced Mary Baker Eddy's Christian Science. The International New Thought Alliance (formed 1914) asserts that sin and illness stem from incorrect thinking. New Thought groups emphasize Jesus as a teacher and healer and proclaim his kingdom as being within each person.
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Thought and thinking are mental forms and processes, respectively ("thought" is both.) Thinking allows beings to model the world and to deal with it effectively according to their objectives, plans, ends and desires. Words referring to similar concepts and processes include cognition, sentience, consciousness, idea, and imagination.