Full Idea
We perform a one-operation when we perform a segregative operation in which a single object is segregated.
Gist of Idea
A one-operation is the segregation of a single object
Source
Philip Kitcher (The Nature of Mathematical Knowledge [1984], 06.3)
Book Reference
Kitcher,Philip: 'The Nature of Mathematical Knowledge' [OUP 1984], p.112
A Reaction
This is part of Kitcher's empirical but constructive account of arithmetic, which I find very congenial. He avoids the word 'unit', and goes straight to the concept of 'one' (which he treats as more primitive than zero).