"I said what I have to say about the modern use of the word "genius" in the preface to the second edition of my "Hereditary Genius." It has only latterly lost its old and usual meaning, which is preserved in the term of an "ingenious" artisan, and has come to be applied to something akin to inspiration. This simply means, as I suppose, though some may think differently, that the powers of unconscious work possessed by the brain are abnormally developed in them. The heredity of these powers has not, I believe, been as yet especially studied. It is strange that more attention has not been given until recently to unconscious brain work, because it is by far the most potent factor in mental operations. Few people, when in rapid conversation, have the slightest idea of the particular form which a sentence will assume into which they have hurriedly plunged, yet through the guidance of unconscious cerebration it develops itself grammatically and harmoniously. I write on good authority in asserting that the best speaking and writing is that which seems to flow automatically shaped out of a full mind."
January 1, 1970
https://en.wikiquote.org/wiki/Francis_Galton