PROP. XXI. The mind can only imagine anything, or remember what is past, while the body endures.

Proof.—The mind does not express the actual existence of its body, nor does it imagine the modifications of the body as actual, except while the body endures (II. viii. Coroll.); and, consequently (II. xxvi.), it does not imagine any body as actually existing, except while its own body endures. Thus it cannot imagine anything (for definition of Imagination, see II. xvii. note), or remember things past, except while the body endures (see definition of Memory, II. xviii. note). Q.E.D.