Whether in science or the arts, if we look for the source of an achievement we can observe that what a man does either repeats or refutes what someone else has done — repeats it in other tones, refines or amplifies or simplifies it, loads or overloads it with meaning; or else rebuts, overturns, destroys, and denies it, but thereby assumes it and has invisibly used it. Opposites are born from opposites.