Full Idea
Surprise is a criterion of error.
Gist of Idea
Surprise is a criterion of error
Source
Bertrand Russell (My Philosophical Development [1959], Ch.15)
Book Reference
Russell,Bertrand: 'My Philosophical Development' [Routledge 1993], p.136
A Reaction
Russell is not too precise about this, but it is a nice point. Surprise is thwarted expectation, which implies prior misjudgement.