Books on Amazon:
Variables/Russell/Goedel: only to enable truth function. - Finite/Infinite/Ramsey: the problem of solving infinite propositions is not so critical. - Gödel: then Russell’s Apercu that propositions about classes can be interpreted as propositions about their elements literally becomes true, provided that n is the number of the (finite) individuals in the world, and provided we neglect the zero class.
Pseudo-variable/Peano/Russell: the symbol (x). φ x denotes a particular proposition and there is no sense of difference between (x). j x and (y). φ y if they occur in the same context. - ((s)> Quine: alphabetical variant) - o is x in (x) φ x not an ambiguous part of an expression and such an expression itself remains the bearer of a very specific meaning despite the ambiguity of the x in φ x. - pseudo-variables: exist if the extension does not go over the entire range - a proposition with an state of affairs x is not a function of x. - Extension: the function of which all or some values are asserted.
Ambiguous assertion and the real variable: any arbitrary value φ x of the function φ x^ can be asserted. - Real Variable: φx. - If x varies, a different proposition results.
Pseudo-variable: is obtained if we put a universal quantifier before it.
Pseudo-Variable: several poss. values can be meant. - Descriptions always contain pseudo-variables - sentences without pseudo-variables: observation sentences E.g. This is red.
Pseudo-Variable/Principia Mathematica/Russell/(s): E.g. (y).φ(x,y), which is a function of x - here y is a pseudo-variable, x is the real variable. - ((s) E.g. everything smaller than x - instead of y it could also say z here).
B. Russell/A.N. Whitehead
Principia Mathematica Frankfurt 1986
Das ABC der Relativitätstheorie Frankfurt 1989
Probleme der Philosophie Frankfurt 1967
Die Philosophie des logischen Atomismus
Eigennamen, U. Wolf (Hg), Frankfurt 1993
Wahrheit und Falschheit
Wahrheitstheorien, G. Skirbekk (Hg), Frankfurt 1996