System of the Fine Arts/Book 1/Chapter 2

We are no more in the times when the fantastic creations of dreams were considered as the announcements of destiny. But it is not necessary at all to trust too much in the lights; and man has not so much changed that he can think without confusion of a dream which would have connection to his more lively affections, as of a sick friend or calumniator, or of an unfaithful woman, or of a son killed in combat. I desire only that the wisdom of days preserves you and preserves me from such dreams; but to believe a little too much of it, if you have them, nothing will preserve you. That to give the understanding that, as soon one pays attention to a dream, the passion turns us away from considering the true causes. It is necessary however to regard this in close fashion, and this is an easy road towards an idea a little hidden, and essential in our subject.

I take a part, in dreams, in the emotions and the rememberances of each. And how to take otherwise? But, to go against the commonplaces, I say that it is necessary to reduce it as much as one can and to carry attention to other causes. Firstly that exterior objects still act on our senses during sleep which give place to some lazy perceptions. For example, noises touch us; a bell, a clock chime, a voice are heard and can be interpreted, therefore perceived although very badly. An odor, of the same. With regard to touch, it never ceases, by the weight of the body, by the heat and the cold, by the contact of clothing, from us to give to thinking. And even the view received across the eyelids from a bright light. It has happened to me after having dreamed of fire and of blood, to perceive finally in awakening me the glimmer of the sun on a red curtain. Some examples of this kind of will offer themselves to the reader, it suffices to think of them.