Full Idea
The problem with Mill is that many of his formulations are imprecise, and he only considers the most rudimentary parts of arithmetic.
Gist of Idea
Mill is too imprecise, and is restricted to simple arithmetic
Source
comment on John Stuart Mill (System of Logic [1843]) by Philip Kitcher - The Nature of Mathematical Knowledge Intro
Book Reference
Kitcher,Philip: 'The Nature of Mathematical Knowledge' [OUP 1984], p.4
A Reaction
This is from a fan of Mill, trying to restore his approach in the face of the authoritative and crushing criticisms offered by Frege. I too am a fan of Mill's approach. Patterns can be discerned in arrangements of pebbles. Infinities are a problem.