Full Idea
A definition as an analysis of an idea into its constituents is inconvenient and, I think, useless; it overlooks the fact that wholes are not, as a rule, determinate when their constituents are given.
Gist of Idea
Definition by analysis into constituents is useless, because it neglects the whole
Source
Bertrand Russell (The Principles of Mathematics [1903], §108)
Book Reference
Russell,Bertrand: 'Principles of Mathematics' [Routledge 1992], p.111
A Reaction
The influence of Leibniz seems rather strong here, since he was obsessed with explaining what creates true unities.