"... Professor Hadamard concludes that the general pattern of invention, or, as it might also be put, of original work, is three-fold : conscious study, followed by unconscious maturing, which leads in turn to the moment of insight or illumination. Thereupon another period of conscious work ensues, the purpose of which is to achieve a synthesis of several elements: the novel idea, its logically deduced consequences including proof, and the traditional knowledge to which the new item is added."
January 1, 1970
https://en.wikiquote.org/wiki/Jacques_Hadamard