Full Idea
The non-mental world can be completely described without the use of any logical word, …but when it comes to the mental world, there are facts which cannot be mentioned without the use of logical words.
Gist of Idea
The physical world doesn't need logic, but the mental world does
Source
Bertrand Russell (An Inquiry into Meaning and Truth [1940], 5)
Book Reference
Russell,Bertrand: 'An Inquiry into Meaning and Truth' [Penguin 1967], p.88
A Reaction
He adds that logical words are not needed for physics, but are needed for psychology. I love Russell's interest in the psychology of logic (in defiance of the anti-psychologism of Frege). See also the ideas of Robert Hanna.
Related Idea
Idea 11058 Logic is explanatorily and ontologically dependent on rational animals [Hanna]