Page:Encyclopædia Britannica, Ninth Edition, v. 7.djvu/476

456 456 DREAM to sleep ? Is dreaming an indication of imperfect sleep which must cease as soon as the higher nervous centres reach a complete repose 1 Is it, on trie other hand, some thing wholly spiritual and independent of sleep as a bodily condition ? Hsre we have two different views arising from different theories of the relation of mind and body. These distinct views of the subject have commonly appeared as answers to the question of fact Are we when asleep always dreaming ] This question was first raised by philosophers in connection with certain conceptions of the soul and its activity. Descartes, who regarded thought as of the essence of personal existence, was naturally led to maintain that the mind is always thinking. &quot; I am,&quot; he says, &quot; I exist, that is certain ; but for how long 1 as long as I think ; for perhaps even it might happen that if I ceased wholly to think I should cease at the same time wholly to exist&quot; (Meditation ii.). Among the Cartesians the proposi tion, the mind is always thinking, became a leading tenet. Locke argues against this supposition. He contends that in sleep men do not always think, or they would be con scious of it. If it is asserted that they dream but they forget it, he replies it is &quot; hard to be conceived &quot; that &quot; the soul in a sleeping man should be this moment busy a-thinking, and the next moment in a waking man not remember nor be able to recollect one jot of all those thoughts.&quot; To suppose that in sleep the soul thinks apart from the body mvolves the absurdity of a double mind, and is further contradicted by the irrationality of dreams (Essay, book ii. ch. i.). Locke was answered by Leibnitz in the Nouveaux Essais, who upheld the Cartesian affirma tion, and maintained that during sleep the mind has always some &quot; little perceptions &quot; or &quot; confused sentiments,&quot; though, according to his doctrine of unconscious perceptions, these need not become objects of conscious attention. That we never sleep without dreaming is further maintained by Kant in his Anthropoloyie, by Jouffroy and others. In his Lectures on Metaphysics, Sir W. Hamilton argues fully for the same idea. He says that during sleep the mind &quot; is never either inactive or wholly unconscious.&quot; He seeks to refute the argument of Locke, that we ought to remember our dreams, by calling attention to the fact that the somnambulist lias no recollection of his dream, and that persons who betray in their expression and utterance the fact of dreaming retain no recollection of the state. He further holds that the continuity of dreaming is proved by the fact that whenever we are suddenly roused from sleep we find ourselves dreaming. While metaphysicians have thus in the main affirmed the continuity of dreams, those who regard mental phenomena as invariably connected with bodily conditions have for the most part viewed dreaming as only an occasional accom paniment of sleep. By some, indeed, dreaming is viewed as confined to the transition state from sleeping to waking, though this view is now rejected by physiologists no less than by metaphysicians. It is true that the great rapidity of dream-thought has been proved, e.g., by the experience of Lord Holland, who fell asleep when listening to some body reading, had a long dream, and yet awoke in time to hear the conclusion of the sentence of which he remembered the beginning. And this takes off from the value of Hamilton s argument that we always find ourselves dream ing when wakened, for such dreaming may clearly be an incident of the transition state. Yet the other facts emphasized by Hamilton, as well as the results of Maury s experiments, to be spoken of presently, show that we may dream when soundly sleeping. On the other hand, we cannot, it is certain, directly prove that we are always dreaming daring sleep. Many physiologists are disposed to regard dreaming as the accompaniment of some slight disturbance, whether arising from the lower organs or from an undue excitability of the brain and its nervous connec tions ; and according to this view the continuity of dreaming would seem to be an improbable supposition. To the physiologist the idea of perfectly unconscious sleep presents no difficulties. The results of experiment show him that the lower bodily (vegetative) functions are in dependent of cerebral activity ; and the phenomena of swooning, the effects of anaesthetics, &c., familiarize him with the temporary suspension of the conscious activity of the brain. Hence the view commonly adopted by physio logists seems to be that dreaming is only an occasional incident of sleep. (See the article on &quot; Sleep and Dreams &quot; by Dr Carpenter in Todd s Ency. of Anat. and Pliysiol] At the same time certain physiologists, as Sir H. Holland (Chapters on Ment. Physiol.] and Sir Benj. Brodie (Psycho logical Inquiries], are disposed to think that dreaming is the rule and not the exception. The question whether we are always dreaming during sleep leads up naturally to the inquiry into the causes or conditions of dreams. This question has been approached from different sides. On the one side, metaphysicians have sought to account for dreaming by some simple theory of a suspension of certain mental faculties. On the other side, writers have tried to explain dreaming as a result of simple bodily operations. We will just glance at one or two of these simple hypotheses. A common view among meta physicians is that the nature of dreaming is amply explained by the absence or suspension of the will. The importance of the cessation of the will s action has been emphasized by Dugald Stewart (Elements of the Phil, of the Human Mind, vol. i. chap. v. sect. 5). Stewart does riot mean that the- will is wholly dormant in sleep, but that it loses its hold on the faculties. By this supposition he seeks to account not only for the incoherence but also for the apparent reality of dream-images. That the absence of the normal processes of volition, especially as involved in attention, con stitutes one important factor in the explanation of dreaming seems to be admitted by all writers, for example, Dr Darwin (Zoonomia), Sir Benj. Brodie, Dr Carpenter, and M. Alf. Maury (Le Sommcil et les Reves). It is doubtful, however, whether this simple hypothesis explains all that Stewart refers to it. Maury objects to Stewart s theory that the will does not wholly lose its command of the bodily organs, &c., in dreams. While great stress has thus been laid by some writers on this negative condition, the suspension of will, others have sought to construct a simple theory of dreaming by supposing the unimpeded action of some special mental faculty. Thus Cudworth (Treatise concerning Eternal and Immutable Morality] reasons, from the orderly coherence of dream-imaginations and the novelty of their combinations, that this state of mind arises from the action of &quot; the phantastical power of the soul,&quot; and not from &quot; any fortuitous dancings of the spirits.&quot; A very curious theory of dreaming as depending on a particular circum scribed faculty of the soul is to be found in Schemer s Das Lelen dcs Traiimes, Dreaming is a decentralization of the movement of life. In waking consciousness the central force, the ego spontaneity, is supreme, in dreaming the activity of the ego becomes purely receptive. The central ego is now merely the point about which the peripheral life plays in perfect freedom. Thus the will (the spontaneous ego) is suspended, and thought loses its categories. On the other hand, the imagination now freed from the ego reaches its perfect unrestrained function. And this func tion is seen in the symbolic representation both of the bodily parts and of the mental stimuli which influence consciousness in sleep. A similar conception of the action of the creative fancy in dreaming is adopted by Dr Johannes Volkelt (Die Traum-pJunntasie.)