Such a position is fortified by the conclusion of those who look at the problem, not so much in terms of attention as in terms of apperception. Apperception, according to Wundt, differs from perception in that while the latter is the appearance of a content in consciousness, the former is its reception into the state of attention. Or, as Stout defines it, apperception is 'the process by which a mental system appropriates a new element, or otherwise receives a fresh determination.'[54] Apperception is, therefore, the final stage of attention, and ultimately, as Wundt remarks, it is one with will. Apperception and will, as most psychologists consider, like attention, are enfeebled and diminished, if not abolished, in sleep.
In dreams, it thus comes about, we accept the facts presented to us—that is the fundamental assumption of dream life—and we argue about those 'facts' with the help of all the mental resources which are at our disposal, only those resources are frequently inadequate. Sometimes they are startlingly inadequate, to such an extent, indeed, that we are unaware of possibilities which would be the very first to suggest themselves to waking consciousness. Thus the lady who wished to send a small sum of money to Ireland is not aware of the existence of postal orders, and when she decides to convey the money herself, she is not aware of the existence of boat-trains, or even of boats; she might have been living in palaeolithic times. She discusses the question in a clear and logical manner with the resources at her disposal, and reaches a rational conclusion, but considerations which would be the first to occur to waking consciousness are at the moment absent from sleeping consciousness; whole mental tracts have been dissociated, switched off from communication with consciousness; they are 'asleep,' even to sleeping consciousness.[55]
The result is that we are not only dominated by the suggestion of our visions, but we are unable adequately to appreciate and criticise the situations which are presented to us. We instinctively continue to reason, and to reason clearly and logically with the material at our disposal, but our reasoning is hopelessly absurd. We perceive in dreams, but we do not apperceive; we cannot, that is to say, test and sift the new experience, and co-ordinate it adequately with the whole body of our acquired mental possessions. The phenomena of dreaming furnish a delightful illustration of the fact that reasoning, in its rough form, is only the crudest and most elementary form of intellectual operation, and that the finer forms of thinking involve much more than logic. 'All the thinking in the world,' as Goethe puts it, 'will not lead us to thought.'
CHAPTER IV
THE SENSES IN DREAMS
All Dreams probably contain both Presentative and Representative Elements—The Influence of Tactile Sensations on Dreams—Dreams excited by Auditory Stimuli—Dreams aroused by Odours and Tastes—The Influence of Visual Stimuli—Difficulty of distinguishing between Actual and Imagined Sensory Excitations—The Influence of Internal Visceral Stimuli on Dreaming—Erotic Dreams—Vesical Dreams—Cardiac Dreams and their Symbolism—Prodromic Dreams—Prophetic Dreams.
At the outset I adopted provisionally the usual classification of dreams into two classes: the peripheral or presentative group, excited by a stimulus from without, and the central or representative group, having its elements in memories. If, however, we look carefully at the matter, in the light of the experiences which we have encountered, it will be found that this classification, however superficially convenient it may be, fails to correspond to any radical duality of dream phenomena. When we closely question our dream experiences, it ceases to be clear that they really fall into two groups at all.
On the one hand, it would appear that most, perhaps, indeed, all dreams that are sufficiently vivid to be clearly remembered on awakening, have received an initial stimulus from some external, or at all events, peripheral source.[56] There is something unusual or uncomfortable in the sleeper's position, or he has been subjected to some slight unusual strain which has modified his nervous condition, or there has been some deviation from his usual diet, or a physiological stress of some kind is making itself felt within him—careful self-questioning constantly reveals the actual or probable existence of some external or certainly peripheral stimulus of this kind. So that we seem entitled to say that in all dreams there is probably a presentative element.