Logical constant

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In logic, a logical constant of a language is a symbol that has the same semantic value under every interpretation of . Two important types of logical constants are logical connectives and quantifiers. The equality predicate (usually written '=') is also treated as a logical constant in many systems of logic.

Some symbols that are commonly treated as logical constants are:

Symbol Meaning in English
T "true"
F "false"
¬ "not"
"implies", "if...then"
"for all"
"there exists", "for some"
= "equals"

For many logical constants also other symbols are commonly used to denote them, such as the symbol "&" for logical and.

One of the fundamental questions in the philosophy of logic is "What is a logical constant?"; that is, what special feature of certain constants makes them logical in nature?[1]Template:Full

See also


  1. Carnap

External links

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