Full Idea
It would be remarkable if a property abstracted from external things could be transferred without any change of sense to events, to ideas and to concepts, like speaking of 'blue ideas' or 'salty concepts'.
Gist of Idea
You can't transfer external properties unchanged to apply to ideas
Source
Gottlob Frege (Grundlagen der Arithmetik (Foundations) [1884], §24)
Book Reference
Frege,Gottlob: 'The Foundations of Arithmetic (Austin)', ed/tr. Austin,J.L. [Blackwell 1980], p.31
A Reaction
Since those phrases make perfectly good metaphorical sense, I presume the Frege was a fairly literal sort of chap. Is this the earliest emergence of the idea of a category mistake?