“When I say that the judgment and reflection abdicate, it should not be inferred that they are abolished and no longer exist, for the imagination could not, unaided by the reason, construct the whimsical and capricious images of dreams.” Relative to the power to work out, during sleep, problems involving long and intricate mental processes, I have already expressed my opinion adversely. In this view, I am not alone. Rosenkranz,[51] whose contributions to psychological science cannot be overestimated, and whose clear and powerful understanding has rarely been excelled, has pointed out how such operations of the understanding are impossible; for, as he remarks, intellectual problems cannot be solved during sleep, for such a thing as intense thought, accompanied by images, is unknown, whilst dreams consist of a series of images connected by loose and imperfect reasoning. Feuchtersleben,[52] referring with approval to this opinion of Rosenkranz, says that he recollects perfectly having dreamt of such problems, and being happy in their solution, endeavored to retain them in his memory; he succeeded, but discovered, on awaking, that they were quite unmeaning, and could only have imposed upon a sleeping imagination. Müller[53] says: “Sometimes we reason more or less correctly in dreams. We reflect on problems and rejoice in their solution. But on awaking from such dreams, the seeming reasoning is frequently found to have been no reasoning at all, and the solution of the problem over which we had rejoiced, to be mere nonsense. Sometimes we dream that another person proposes an enigma; that we cannot solve it and that others are equally incapable of doing so; but that the person who proposed it, himself gives the explanation. We are astonished at the solution we had so long labored in vain to find. If we do not immediately awaken and afterwards reflect on this proposition of an enigma in our dream, and on its apparent solution, we think it wonderful; but if we awake immediately after the dream, and are able to compare the answer with the question, we find that it was mere nonsense.” And in regard to the knowledge that we are dreaming, the same author[54] observes that: