There are, however, some phenomena, which, considered superficially, appear to support the opinion of these philosophers; to announce a faculty in the human soul of producing ideas within itself, without any exterior aid; these are _dreams_, in which the interior organ of man, deprived of objects that move it visibly, does not, however, cease to have ideas--to be set in activity--to be modified in a manner that is sufficiently sensible--to have an influence upon his body. But if a little reflection be called in, the solution to this difficulty will be found: it will be perceived that, even during sleep, his brain is supplied with a multitude of ideas, with which the eye or time before has stocked it; these ideas were communicated to it by exterior or corporeal objects, by which they have been modified: it will be found that these modifications renew themselves, not by any spontaneous, not by any voluntary motion on its part, but by a chain of involuntary movements which take place in his machine, which determine, which excite those that give play to the brain; these modifications renew themselves with more or less fidelity, with a greater or lesser degree of conformity to those which it has anteriorly experienced. Sometimes in dreaming, he has memory, then he retraces to himself the objects which have struck him faithfully;--at other times, these modifications renew themselves without order, and without connection, very differently from those, which real objects have before excited in his interior organ. If in a dream he believes he sees a friend, his brain renews in itself the modifications or the ideas which this friend had formerly excited--in the same order that they arranged themselves when his eyes really beheld him--this is nothing more than an effect of memory. If in his dream he fancies he sees a monster which has no model in nature, his brain is then modified in the same manner that it was by the particular, by the detached ideas, with which it then does nothing more than compose an ideal whole; by assembling, and associating, in a ridiculous manner, the scattered ideas that were consigned to its keeping; it is then, that in dreaming he has imagination.