Full Idea
The theory of classes is completely superfluous in mathematics. This is connected with the fact that the generality required in mathematics is not accidental generality.
Gist of Idea
The theory of classes is superfluous in mathematics
Source
Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.031)
Book Reference
Wittgenstein,Ludwig: 'Tractatus Logico-Philosophicus (Pears)', ed/tr. Pears,D. /McGuinness,B. [RKP 1961], p.59
A Reaction
This fits Russell's no-class theory, which rests everything instead on propositional functions.