'The sleeper's visions are as turbulent as his day.'

[I]t was a very frequent theme of moralists that virtue is marked by the disappearance of dreams that translate the appetites and involuntary movements of the mind and body. "The sleeper's visions," said Seneca, "are as turbulent as his day." Plutarch cited Zeno in affirming that it is a sign of progress when a person no longer dreams that he derives pleasure from indecent actions. And he alluded to those individuals who have enough strength in their waking hours to combat and resist their passions, but who at night, "throwing off opinions and laws," cease to feel any shame: then there awakens what is immoral and licentious within them.

—Michel Foucault, The Care of the Self (The History of Sexuality, Volume 3) (1984) (trans. R.H. 1986)