Full Idea
Russell explained ¬p by saying that ¬p is true if p is false and false if p is true. But this is not an explanation of negation, for it might apply to propositions other than the negative.
Gist of Idea
Negations are not just reversals of truth-value, since that can happen without negation
Source
comment on Bertrand Russell (The Principles of Mathematics [1903]) by Ludwig Wittgenstein - Lectures 1930-32 (student notes) B XI.3
Book Reference
Wittgenstein,Ludwig: 'Lectures in Cambridge 1930-32', ed/tr. Lee,Desmond [Blackwell 1980], p.52
A Reaction
Presumably he is thinking of 'the light is on' and 'the light is off'. A very astute criticism, which seems to be correct. What would Russell say? Perhaps we add that negation is an 'operation' which achieves flipping of the truth-value?