Intellect, in civilised man, like artistic capacity, has occasionally been developed beyond the point where it is useful to the individual
 Bertrand Russell, Mysticism and Logic and Other Essays (1910). copy citation

Context

“The fact is, of course, that both intuition and intellect have been developed because they are useful, and that, speaking broadly, they are useful when they give truth and become harmful when they give falsehood. Intellect, in civilised man, like artistic capacity, has occasionally been developed beyond the point where it is useful to the individual; intuition, on the other hand, seems on the whole to diminish as civilisation increases. It is greater, as a rule, in children than in adults, in the uneducated than in the educated. [16] Probably in dogs it exceeds anything to be found in human beings.” source