"[M]an is a machine... in the whole universe there is but a single Substance differently modified. ...Experience has thus spoken to me in behalf of reason; and in this way I have combined the two. ...Against so strong and solid an oak, what could the weak reeds of theology, of metaphysics, and of the schools, avail... Need I say that I refer to the empty and trivial notions, to the pitiable and trite arguments that will be urged (as long as the shadow of prejudice or of superstition remains on earth) for the supposed incompatibility of two substances which meet and move each other unceasingly?"