The logical constants, by contrast, have the same meaning in all interpretations.

There are only two basic values of logical constants: and .

(Here the equality relation is taken as a logical constant.)

The equality predicate (usually written '=') is also treated as a logical constant in many systems of logic.

One of the fundamental questions in the philosophy of logic is "What is a logical constant?"

A logical constant denoting a tautology in logic.

Some symbols that are commonly treated as logical constants are:

Understanding logical constants: a realist's account (1987), British Academy lecture.

Here, denotes the logical constant "false", so is a formula that holds only if n is the empty set.

Two important types of logical constants are logical connectives and quantifiers.

In a deviation, the usual logical constants are used, but are given a different meaning than usual.

Logical constant -

In logic, a logical constant of a language is a symbol that has the same semantic value under every interpretation of .

Thus, besides the traditional numeric and logical constants, Euler introduces the following additional types:

Logical Constants.

Logical constants

Logical constant, a symbol in symbolic logic that has the same meaning in all models, such as the symbol "=" for "equals"

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

Stanford Encyclopedia of Philosophy entry on logical constants

character or logical constants, whose values may not overlap within or between

Logical truth and logical constants

For instance there are logical constants which do not refer to any idea, but rather serve as a form of punctuation in the language (e.g. parentheses).

Logical truths are those necessary truths that are necessarily true owing to the meaning of their logical constants only.

In predicate logic, a universal quantification is a type of quantifier, a logical constant which is interpreted as "given any" or "for all".

Logical constants, including logical connectives and quantifiers, can all be reduced conceptually to logical truth.