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Definition: logic from The Penguin Dictionary of Psychology

That normative branch of philosophy that deals with the criteria of validity in thought, the canons of correct predication and the principles of reasoning and demonstration. Logic concerns only the reasoning process, not the end result. Incorrect conclusions can be reached through logical means if the original assumptions are faulty. See also FORMAL *LOGIC, SYMBOLIC *LOGIC.


logic

From The Columbia Encyclopedia
the systematic study of valid inference. A distinction is drawn between logical validity and truth. Validity merely refers to formal properties of the process of inference. Thus, a conclusion whose value is true may be drawn from an invalid argument, and one whose value is false, from a valid sequence. For example, the argument All professors are brilliant; Smith is a professor, therefore, Smith is brilliant is a valid inference, but the argument All professors are brilliant; Smith is brilliant; therefore, Smith is a professor is an invalid inference, even if Smith is a professor. In Western thought, systematic logic is considered to have begun with Aristotle's collection of treatises, the Organon [tool]. Aristotle introduced the use of variables: While his contemporaries illustrated principles by the use of examples, Aristotle generalized, as in: All x are y; all y are z; therefore, all x are z. Aristotle posited three laws as basic to all valid thought: the law of identity, A is A; …
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Full text Article LOGIC

From Key Ideas in Linguistics and the Philosophy of Language
Logic is the study of argument. Logic is central to philosophy, linguistics and many other fields. See also : Logical Form ; Port-Royal Logic ; Truth Value Key Thinkers : Aristotle ; Frege, Gottlob ; Russell, Bertrand An argument is an attempt to persuade using reasoning. Arguments are composed of…
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Full text Article logic

From Philip's Encyclopedia
Branch of philosophy that deals with the processes of valid reasoning and argument. Logic defines the way in which one thing may be said to follow from, or be consequent upon, another. This is known as deductive logic. Inductive logic is when a general conclusion is drawn from a particular fact or…
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Full text Article LOGIC

From A Dictionary of Philosophical Logic
Logic is the study of arguments , and the various methods of logic are used to investigate the structure of arguments and to classify them, in terms of their structure, into those that ought to be persuasive and those that ought not to be persuasive. Although the primary purpose of logic is to…
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Full text Article LOGIC

From Dictionary of Visual Discourse: A Dialectical Lexicon of Terms
Logic derives from the Greek word logos with its multiplicity of related and conjugate meanings (gathering together ( lego ), word, speech, language, reason and reasoning, thought and thinking, accounting, rationality, coherence, intelligibility, and so on). We thus have four main logological…
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Full text Article LOGIC

From Gaither's Dictionary of Scientific Quotations
Greek philosopher To say of what is that it is not, or of what is not that it is, is false, while to say of what is that it is, or of what is not that it is not, is true. In Great Books of the Western World (Volume 8 ) Metaphysics Book IV, Chapter 7 (p. 531 ) Encyclopædia Britannica, Inc. Chicago…
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Full text Article Logic

From The Classical Tradition
In 1787 Kant praised Aristotle's logic, writing that it was "to all appearance a closed and completed body of doctrine" ( Critique of Pure Reason , B viii). His words capture the reality that for most of Western educational history, Aristotle's logic has been an essential part of the curriculum. …
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Full text Article logic

From The Hutchinson Unabridged Encyclopedia with Atlas and Weather Guide
Branch of philosophy that studies valid reasoning and argument. It is also the way in which one thing may be said to follow from, or be a consequence of, another (deductive logic). Logic is generally divided into the traditional formal logic of Aristotle and the symbolic logic derived from Friedrich…
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Full text Article logicism

From Cambridge Dictionary of Philosophy
the thesis that mathematics, or at least some significant portion thereof, is part of logic. Modifying Carnap's suggestion (in “The Logicist Foundation for Mathematics,” first published in Erkenntnis , 1931), this thesis is the conjunction of two theses – expressibility logicism: mathematical…
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Full text Article logic

From The Chambers Dictionary
the science and art of reasoning correctly; the science of the necessary laws of thought; the principles of any branch of knowledge; sound reasoning; individual method of reasoning; convincing and compelling force (eg of facts or events); basis of operation as designed and effected in a computer, …
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Full text Article logic

From The American Heritage(R) Dictionary of the English Language
The study of the principles of reasoning, especially of the structure of propositions as distinguished from their content and of method and validity in deductive reasoning. a. A system of reasoning: Aristotle's logic. b. A mode of reasoning: By that logic, we should sell the company tomorrow. c. The…
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