In order to illustrate how oddly our seemingly rational dreams caricature the operations of waking thought, I may, perhaps, be allowed to record two of my own dreams, of which I took careful note at the time.
On the first occasion I went "in my dream" to the "Stores" in August, and found the place empty. A shopman brought me some large fowls. I asked their price, and he answered, "Tenpence a pound." I then asked their weight, so as to get an idea of their total cost, and he replied, "Forty pounds." Not in the least surprised, I proceeded to calculate their cost: 40x10=400÷12=33⅓. But, oddly enough, I took this quotient as pence, just as though I had not already divided by 12, and so made the cost of a fowl to be 2s. 9d., which seemed to me a fair enough price.
In my second dream I was at Cambridge, among a lot of undergraduates. I saw a coach drive up with six horses. Three undergraduates got out of the coach. I asked them why they had so many horses, and they said, "Because of the luggage." I then said, "The luggage is much more than the undergraduates. Can you tell me how to express this in mathematical symbols? This is the way: if x is the weight of an undergraduate, then x + xn represents the weight of an undergraduate and his luggage together." I noticed that this sally was received with evident enjoyment.[99]
We may say, then, that the structure of our dreams, equally with the fact of their completely illusory character, points to the conclusion that during sleep, just as in the moments of illusion in waking life, there is a deterioration of our intellectual life. The highest intellectual activities answering to the least stable nervous connections are impeded, and what of intellect remains corresponds to the most deeply organized connections.
In this way, our dream-life touches that childish condition of the intelligence which marks the decadence of old age and the encroachments of mental disease. The parallelism between dreams and insanity has been pointed out by most writers on the subject. Kant observed that the madman is a dreamer awake, and more recently Wundt has remarked that, when asleep, we "can experience nearly all the phenomena which meet us in lunatic asylums." The grotesqueness of the combinations, the lack of all judgment as to consistency, fitness, and probability, are common characteristics of the short night-dream of the healthy and the long day-dream of the insane.[100]
But one great difference marks off the two domains. When dreaming, we are still sane, and shall soon prove our sanity. After all, the dream of the sleeper is corrected, if not so rapidly as the illusion of the healthy waker. As soon as the familiar stimuli of light and sound set the peripheral sense-organs in activity, and call back the nervous system to its complete round of healthy action, the illusion disappears, and we smile at our alarms and agonies, saying, "Behold, it was a dream!"
On the practical side, the illusions and hallucinations of sleep must be regarded as comparatively harmless. The sleeper, in healthy conditions of sleep, ceases to be an agent, and the illusions which enthral his brain have no evil practical consequences. They may, no doubt, as we shall see in a future chapter, occasionally lead to a subsequent confusion of fiction and reality in waking recollection. But with the exception of this, their worst effect is probably the lingering sense of discomfort which a "nasty dream" sometimes leaves with us, though this may be balanced by the reverberations of happy dream-emotions which sometimes follow us through the day. And however this be, it is plain that any disadvantages thus arising are more than made good by the consideration that our liability to these nocturnal illusions is connected with the need of that periodic recuperation of the higher nervous structures which is a prime condition of a vigorous intellectual activity, and so of a triumph over illusion during waking life.
For these reasons dreams may properly be classed with the illusions of normal or healthy life, rather than with those of disease. They certainly lie nearer this region than the very similar illusions of the somnambulist, which with respect to their origin appear to be more distinctly connected with a pathological condition of the nervous system, and which, with respect to their practical consequences may easily prove so disastrous.
After-Dreams.
In concluding this account of dreams, I would call attention to the importance of the transition states between sleeping and waking, in relation to the production of sense-illusion. And this point may be touched on here all the more appropriately, since it helps to bring out the close relation between waking and sleeping illusion. The mind does not pass suddenly and at a bound from the condition of dream-fancy to that of waking perception. I have already had occasion to touch on the "hypnagogic state," that condition of somnolence or "sleepiness" in which external impressions cease to act, the internal attention is relaxed, and the weird imagery of sleep begins to unfold itself. And just as there is this anticipation of dream-hallucination in the presomnial condition, so there is the survival of it in the postsomnial condition. As I have observed, dreams sometimes leave behind them, for an appreciable interval after waking, a vivid after-impression, and in some cases even the semblance of a sense-perception.