"I have touched upon loneliness, the dweller in the forest as represented by Thoreau, the isolated man in the room who was Hawthorne, and such wandering recluse scientists as Darwin and Wallace. This loneliness, in the case of literary men, frequently leads to an intense self-examination. ‘Who placed us with eyes between a microscopic and telescopic world?’ questions Thoreau. ‘I have the habit of attention to such excess that my senses get no rest, but suffer from a constant strain.’
Thoreau here expresses the intense self-awareness which is both the burden and delight of the true artist. It is not merely the fact that such men create their universe as surely as shipwrecked bits of life run riot and transform themselves on oceanic islands. It is that in this supremely heightened consciousness of genius the mind insists on expression. The spirit literally cannot remain within itself. It will talk if it talks on paper only to itself, as did Thoreau."
— Loren C. Eiseley, Collected Essays on Evolution, Nature, and the Cosmos