Full Idea
There is always unavoidably something psychological about inference.
Gist of Idea
There is always something psychological about inference
Source
Bertrand Russell (Introduction to Mathematical Philosophy [1919], XIV)
Book Reference
Russell,Bertrand: 'Introduction to Mathematical Philosophy' [George Allen and Unwin 1975], p.149
A Reaction
Glad to find Russell saying that. Only pure Fregeans dream of a logic that rises totally above the minds that think it. See Robert Hanna on the subject.