『エチカ』、第IV部、定理3

This is evident from the axiom of this part. For, when man is given, there is something else--say A--more powerful; when A is given, there is something else--say B--more powerful than A, and so on to infinity; thus the power of man is limited by the power of some other thing, and is infinitely surpassed by the power of external causes. Q.E.D.