Single Idea 18722

[catalogued under 5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / c. not]

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?