Full Idea
Pure mathematics ...according to my conception is nothing other than pure set theory.
Gist of Idea
Pure mathematics is pure set theory
Source
George Cantor (works [1880], I.1), quoted by Penelope Maddy - Naturalism in Mathematics I.1
Book Reference
Maddy,Penelope: 'Naturalism in Mathematics' [OUP 2000], p.21
A Reaction
[an unpublished paper of 1884] So right at the beginning of set theory this claim was being made, before it was axiomatised, and so on. Zermelo endorsed the view, and it flourished unchallenged until Benacerraf (1965).