I have always been amazed at the way an ordinary observer lends so much more credence and attaches so much more importance to waking events than to those occurring in dreams. It is because man, when he ceases to sleep, is above all the plaything of his memory, and in its normal state memory takes pleasure in weakly retracing for him the circumstances of the dream, in stripping it of any real importance, and in dismissing the only determinant from the point where he thinks he has left it a few hours before: this firm hope, this concern. He is under the impression of continuing something that is worthwhile. Thus the dream finds itself reduced to a mere parenthesis, as is the night. And, like the night, dreams generally contribute little to furthering our understanding. This curious state of affairs seems to me to call for certain reflections.