"We do not include the pleasures we enjoy in sleep in the inventory of the pleasures we have experienced in the course of our existence. To take only the most grossly sensual of them all, which of us, on waking, has not felt a certain irritation at having experienced in his sleep a pleasure which, if he is anxious not to tire himself, he is not, once he is awake, at liberty to repeat indefinitely during that day. It seems a positive waste."