Genius is conditioned by a passionate temperament, and a phlegmatic genius is inconceivable
 Arthur Schopenhauer, The World as Will and Representation (1819). copy citation

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Author Arthur Schopenhauer
Source The World as Will and Representation
Topic genius temperament
Date 1819
Language English
Reference
Note Translated by R. B. Haldane and J. Kemp
Weblink http://www.gutenberg.org/files/40868/40868-h/40868-h.html

Context

“The difference of the whole manner of existence which the extremes of the gradation of intellectual capacity establish between man and man is so great that that between a king and a day labourer seems small in comparison. And here also, as in the case of the species of animals, a connection between the vehemence of the will and the height of the intellect can be shown. Genius is conditioned by a passionate temperament, and a phlegmatic genius is inconceivable: it seems as if an exceptionally vehement, thus a violently longing, will must be present if nature is to give an abnormally heightened intellect, as corresponding to it; while the merely physical account of this points to the greater energy with which the arteries of the head move the brain and increase its turgescence.” source