logical constant

logic

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model theory

  • David Hilbert
    In metalogic: Characterizations of the first-order logic

    …of equality as the “logical constants” is assumed to be the correct one. There remains the question, however, of justifying the particular choice of logical constants. One might ask, for example, whether “For most x” or “For finitely many x” should not also be counted as logical constants. Lindström…

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philosophy of logic

  • In philosophy of logic: Nature and varieties of logic

    …certain specific terms, often called logical constants. Whether they can be given an intrinsic characterization or whether they can be specified only by enumeration is a moot point. It is generally agreed, however, that they include (1) such propositional connectives as “not,” “and,” “or,” and “if–then” and (2) the so-called…

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constant, a number, value, or object that has a fixed magnitude, physically or abstractly, as a part of a specific operation or discussion. In mathematics the term refers to a quantity (often represented by a symbol—e.g., π, the ratio of a circle’s circumference to its diameter) that does not change in a certain discussion or operation, or to a variable that can assume only one value. In logic it is a term with an invariant denotation (any symbol with a fixed designation, such as a connective or quantifier).

For discussion of physical constants, see physical constant.