From Bento’s Sketchbook, a quote from Spinoza’s Ethics:

“We sense and experience that we are eternal.  For the mind no less senses those things which it conceives in understanding than those which it has in the memory.  For the eyes of the mind by which it sees things and observes them are proofs.  So although we do not remember that we existed before the body, we sense nevertheless that our mind in so far as it involves the essence of the body under a species of eternity is eternal and its existence cannot be defined by time or explained by duration.”

(Ethics, Part V, Proposition XXIII)