|Variables, philosophy: variables are symbols in statements or logical formulas, in the place of which various, more precise determinations, such as constants or names of objects, can be inserted. In logic, free and bound variables are distinguished. Free variables, which are not bound by a quantifier such as (Ex) or (x), do not form a statement yet but a statement function such as e.g. "Fx" - "Something is F". Numbers or objects are not variable entities. The variability consists in the applicability of more than one possible value. See also free variables, bound variables, constants, individual constants, individual variables, substitution, substitutability, logic, statements, statement function, formulas._____________Annotation: The above characterizations of concepts are neither definitions nor exhausting presentations of problems related to them. Instead, they are intended to give a short introduction to the contributions below. – Lexicon of Arguments.|
Books on Amazon
Variable/Mates: for them names or marks are used - values: include all objects, which can be designated by these expressions (Convention).
no changeable things, also no names of changeable things.
Variable/free/bound/Mates: E.g. "(x)F"x": here bound for the second time - problem: simultaneously within "F"x" free. - ((S) considered without quantifier.
and formulas (if used) may occur bound.
(s) an entire formula always occurs free of course._____________Explanation of symbols: Roman numerals indicate the source, arabic numerals indicate the page number. The corresponding books are indicated on the right hand side. ((s)…): Comment by the sender of the contribution.
Elementare Logik Göttingen 1969