Nature has not intended mankind to work from eight in the morning until midnight without that refreshment of blessed oblivion which, even if it only lasts twenty minutes, is sufficient to renew all the vital forces.

You must sleep sometime between lunch and dinner, and no halfway measures. Take off your clothes and get into bed. That's what I always do.

My mind is a chest of drawers. When I wish to deal with a subject, I shut all the drawers but the one in which the subject is to be found. When I am wearied, I shut all the drawers and go to sleep.

Six hours sleep for a man, seven for a woman and eight for a fool.

Indeed, it is only by means of the rigid and regular web of concepts that the waking man clearly sees that he is awake; and it is precisely because of this that he sometimes thinks that he must be dreaming when this web of concepts is torn by art.

Sleep is like a drug. Take too much at a time and it makes you dopey. You lose time and opportunities.