Sleep and Its Derangements

by William A. Hammond

Now I cannot conceive what connection the judgment has with this power. In the case of alarm clocks set to go off at a certain time, the judgment, as Jouffroy[56] asserts, may take cognizance of the impression made upon the ear, and establish the relation between it and the wish to awake at a certain time. But in cases where the awaking is the result of an idea conceived before going to sleep, and which is not subsequently recalled, the judgment cannot act, for this faculty is only exercised upon ideas which are submitted to it. The brain is, as it were, wound up like the alarm clock and set to a certain hour. When that hour arrives, an explosion of nervous force takes place, and the individual awakes.

Fosgate[57] asserts that the power of judging during sleep is probably as good as when we are awake, for decisions are made only on the premises presented in either case, and if those in the former condition are absurd or unreasonable, the conclusion will likewise be faulty. But this is not very accurate reasoning; for it is as much the province of the judgment to determine the validity of the premises as it is to draw a conclusion from them, and if it cannot recognize the falsity or truth of propositions the irrational character of which would be readily perceived during wakefulness, there is not much to be said in favor of its power.

In fact, however, the conclusions formed in dreams are often without any logical relation with the premises. Thus, when an individual dreams, as in the instance previously quoted, that he is a column of stone, it is contrary to all experience to deduce therefrom the conclusion that he can see rocks crumbling around him, and can reflect upon the mutability of all things. The premise of his being a stone pillar being submitted to the judgment, the proper conclusion would be that he is composed of inorganic material, is devoid of life, and consequently not possessed of either sensation or understanding.

Why the judgment is not properly exercised during sleep we do not know. Dr. Philip[58] believes that in this condition ideas flow so rapidly that they are not submitted to the full power of the judgment, and that hence the absurdity which characterizes them is not perceived. But this explanation is by no means satisfactory; for a merely swift succession of ideas is no very serious bar to correct judgment, and when the thoughts are as preposterous as those which so often occur in dreams, they present no obstacle at all to a proper estimation of them by the healthy mind. The cause probably resides in some alteration in the circulation of the blood in that part of the brain which presides over the judgment, whereby its power is suspended and the imagination left free to fill the mind with its incongruous and fantastic images.

As regards the will, we find very opposite opinions entertained relative to its activity; but no one, so far as I am aware, appears to have had correct views upon the subject. Without going into a full discussion of the views enunciated, it will be sufficient to refer to the ideas on the point in question which have been expressed by some of the most eminent philosophers and physiologists.

In the course of his remarks on sleep, Darwin[59] repeatedly alleges that during this condition the action of the will is entirely suspended; but he falls into the singular error of confounding volition with the power of motion. Thus he says:

“When by one continued posture in sleep some uneasy sensations are produced, we either gradually awake by the exertion of volition, or the muscles connected by habit with such sensations alter the position of the body; but where the sleep is uncommonly profound, and these uneasy sensations great, the disease called the incubus or nightmare is produced. Here the desire of moving the body is painfully exerted; but the power of moving it, or volition, is incapable of action till we are awake.”

In consequence of this misapprehension of the nature of the will, it is not easy to arrive at Darwin’s ideas on the subject; and the attempt is rendered still more difficult from the fact that though he repeatedly states that volition is entirely suspended during sleep, he yet in the first part of the foregoing quotation makes an individual awake by the gradual exercise of the power of the will; and then in the last part of the same paragraph asserts that volition is incapable of action till sleep is over.

Mr. Dugald Stewart[60] contends that during sleep the power of volition is not suspended, but that those operations of the mind and body which depend on volition cease to be exercised. In his opinion the will loses its influence over all our powers both of mind and body in consequence of some physical alteration in the system which we shall never probably be able to explain. To show in full the views of so distinguished a philosopher as Mr. Stewart, I quote the following extracts from his remarks on the subject:

“In order to illustrate this conclusion [the one above stated] a little further, it may be proper to remark that if the suspension of our voluntary operations in sleep be admitted as a fact, there are only two suppositions which can be formed regarding its cause. The one is that the power of volition is suspended; the other that the will loses its influence over those faculties of the mind and those members of the body which during our waking hours are subjected to its authority. If it can be shown then that the former supposition is not agreeable to fact, the truth of the latter seems to follow as a necessary consequence.