From these different observations, we are authorized to conclude, that the same laws of association which regulate the train of our thoughts while we are awake, continue to operate during sleep. I now proceed to consider, how far the circumstances which discriminate dreaming from our waking thoughts, correspond with those which might be expected to result from the suspension of the influence of the will.

VO

1. If the influence of the will be suspended during sleep, all our luntary operations, such as recollection, reasoning, &c. must also be suspended.

That this really is the case, the extravagance and inconsistency of our dreams are sufficient proofs. We frequently confound together times and places the most remote from each other; and, in the course of the same dream, conceive the same person as existing in different parts of the world. Sometimes we imagine ourselves conversing with a dead friend, without remembering the circumstances of his death, although perhaps it happened but a few days before, and affected us deeply. All this proves clearly, that the subjects which then occupy our thoughts, are such as present themselves to the mind spontaneously; and that we have no power of employing our reason in comparing together the different parts of our dreams, or even of exerting an act of recollection, in order to ascertain how far they are consistent and possible.

The process of reasoning, in which we sometimes fancy ourselves to be engaged during sleep, furnish no exception to the foregoing observation; for although every such process, the first time we form it, implies volition; and, in particular, implies a recollection of the premises, till we arrive at the conclusion; yet when a number of truths have been often presented to us as necessarily connected with each other, this series may afterwards pass through the mind, according to the laws of association, without any more activity on our part, than in those trains of thought which are the most loose and incoherent. Nor is this mere theory. I may venture to appeal to the consciousness of every man accustomed to dream, whether his reasonings during sleep do not seem to be carried on without any exertion of his will, and with a degree of facility, of which he was never conscious while awake. Mr. Addison, in one of his Spectators, has made this observation; and his testimony, in the present instance, is of the greater weight, that he had no particular theory on the subject to support. "There is not" (says he) "a more "painful action of the mind than invention, yet in dreams, it works with "that ease and activity, that we are not sensible when the faculty is em"ployed. For instance, I believe every one, sometime or other, dreams "that he is reading papers, books, or letters; in which case the inven"tion prompts so readily, that the mind is imposed on, and mistakes its "own suggestions for the compositions of another."*

2. If the influence of the will during sleep be suspended, the mind will remain as passive, while its thoughts change from one subject to another, as it does during our waking hours, while different perceptible objects are presented to our senses.

Of this passive state of the mind in our dreams, it is unnecessary to multiply proofs; as it has always been considered as one of the most extraordinary circumstances with which they are accompanied. If our dreams, as well as our waking thoughts, were subject to the will, is it not natural to conclude, that, in the one case, as well as in the other, we

* No. 487.

would endeavour to banish, as much as we could, every idea which had a tendency to disturb us; and detain those only which we found to be agreeable? So far, however, is this power over our thoughts from being exercised, that we are frequently oppressed, in spite of all our efforts to the contrary, with dreams which affect us with the most painful emotions. And, indeed, it is matter of vulgar remark, that our dreams are, in every case, involuntary on our part; and that they appear to be obtruded on us by some external cause. This fact appeared so unaccouritable to the late Mr. Baxter, that it gave rise to his very whimsical thecry, in which he ascribes dreams to the immediate influence of separate spirits on the mind.

3. If the influence of the will be suspended during sleep, the conceptions which we then form of sensible objects will be attended with a belief of their real existence, as much as the perception of the same objects is while we are awake.

In treating of the power of Conception, I formerly observed, that our belief of the separate and independent existence of the objects of our perceptions, is the result of experience; which teaches us that these perceptions do not depend on our will. If I open my eyes, I cannot prevent myself from seeing the prospect before me. The case is differ

ent with respect to our conceptions. While they occupy the mind, to the exclusion of every thing else, I endeavoured to shew, that they are always accompanied with belief; but as we can banish them from the mind, during our waking hours, at pleasure, and as the momentary belief which they produce, is continually checked by the surrounding objects of our perceptions, we learn to consider them as fictions of our own creation; and, excepting in some accidental cases, pay no regard to them in the conduct of life. If the doctrine, however, formerly stated with respect to conception, be just, and if, at the same time, it be allowed, that sleep suspends the influence of the will over the train of our thoughts, we should naturally be led to expect, that the same belief which accompanies perception while we are awake, should accompany the conceptions which occur to us in our dreams. It is scarcely necessary for me to remark, how strikingly this conclusion coincides with acknowledged facts.

May it not be considered as some confirmation of the foregoing doctrine, that when opium fails in producing complete sleep, it commonly produces one of the effects of sleep, by suspending the activity of the mind, and throwing it into a reverie; and that while we are in this state, our conceptions frequently affect us nearly in the same mauner, as if the objects conceived were present to our senses ?*

Another circumstance with respect to our conceptions during sleep, deserves our notice. As the subjects which we then think upon, occupy the mind exclusively; and as the attention is not diverted by the objects of our external senses, our conceptions must be proportionably lively and steady. Every person knows how faint the conception is which we form of any thing, with our eyes open, in comparison of what we can form with our eyes shut and that, in proportion as we can suspend the exercise of all our other senses, the liveliness of our conception increases. To this cause is to be ascribed, in part, the effect which the

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See the Baron de TOTT's Account of the Opium-takers at Constantinople. 22

VOL. I.

dread of spirits in the dark has on some persons, who are fully convinced in speculation, that their apprehensions are groundless; and to this also is owing the effect of any accidental perception in giving them a momentary relief from their terrors. Hence the remedy which nature points out to us, when we find ourselves overpowered by imagination. If every thing around us be silent, we endeavour to create a noise, by speaking aloud, or beating with our feet; that is, we strive to divert the attention from the subjects of our imagination, by presenting an object to our powers of perception. The conclusion which I draw from these observations is, that, as there is no state of the body in which our perceptive powers are so totally unemployed as in sleep, it is natural to think, that the objects which we conceive or imagine, must then make an impression on the mind, beyond comparison greater, than any thing of which we can have experience while awake.

From these principles may be derived a simple, and, I think, satisfactory explanation of what some writers have represented as the most mysterious of all the circumstances connected with dreaming; the inaccurate estimate we are apt to form of Time, while we are thus employed; an inaccuracy which sometimes extends so far, as to give to a single instant the appearance of hours, or perhaps of days. A sudden noise, for example, suggests a dream connected with that perception; and, the moment afterwards, this noise has the effect of waking us, and yet, during that momentary interval, a long series of circumstances has passed before the imagination. The story quoted by Mr. Addison* from the Turkish Tales, of the Miracle wrought by a Mahometan Doctor, to convince an infidel Sultan, is, in such cases, nearly verified.

The facts I allude to at present are generally explained by supposing, that, in our dreams, the rapidity of thought is greater than while we are awake: but there is no necessity for having recourse to such a supposition. The rapidity of thought is, at all times, such, that, in the twink. ling of an eye, a crowd of ideas may pass before us, to which it would require a long discourse to give utterance, and transactions may be conceived, which it would require days to realize. But, in sleep, the conceptions of the mind are mistaken for realities; and, therefore, our estimates of time will be formed, not according to our experience of the rapidity of thought, but according to our experience of the time requisite for realizing what we conceive. Something perfectly analogous to this may be remarked in the perceptions we obtain by the sense of sight. When I look into a shew-box, where the deception is imperfect, I see only a set of paltry daubings of a few inches diameter; but, if the representation be executed with so much skill, as to convey to me the idea of a distant prospect, every object before me swells in its dimensions, in proportion to the extent of space which I conceive it to occupy, and what seemed before to be shut up within the limits of a small wooden frame, is magnified, in my apprehension, to an immense landscape of woods, rivers, and mountains.

The phenomena which we have hitherto explained, take place when sleep seems to be complete; that is, when the mind loses its influence over all those powers whose exercise depends on its will. There are, however, many cases in which sleep seems to be partial; that is, when

SPECTATOR, No. 94.

the mind loses its influence over some powers, and retains it over others. In the case of the somnambuli, it retains its power over the limbs, but it possesses no influence over its own thoughts, and scarcely any over the body, excepting those particular members of it which are employed in walking. In madness, the power of the will over the body remains undiminished, while its influence in regulating the train of thought is in a great measure suspended; either in consequence of a particular idea, which engrosses the attention, to the exclusion of every thing else, and which we find it impossible to banish by our efforts; or in consequence of our thoughts succeeding each other with such rapidity, that we are unable to stop the train. In both of these kinds of madness, it is worthy of remark, that the conceptions or imaginations of the mind becoming independent of our will, they are apt to be mistaken for actual percep tions, and to affect us in the same manner.

By means of this supposition of a partial sleep, any apparent exceptions, which the history of dreams may afford to the general principles already stated, admit of an easy explanation.

Upon reviewing the foregoing observations, it does not occur to me, that I have in any instance transgressed those rules of philosophizing, which, since the time of Newton, are commonly appealed to, as the tests of sound investigation. For, in the first place, I have not supposed any causes which are not known to exist; and secondly, I have shewn, that the phenomena under our consideration are necessary consequences of the causes to which I have referred them. I have not supposed that the mind acquires in sleep any new faculty of which we are not conscious while awake; but only (what we know to be a fact) that it retains some of its powers, while the exercise of others is suspended: and I have deduced synthetically the known phenomena of dreaming, from the eration of a particular class of our faculties, unconnected by the operation of another. I flatter myself, therefore, that this inquiry will not only throw some light on the state of the mind in sleep, but that it will have a tendency to illustrate the mutual adaptation and subserviency which exists among the different parts of our constitution, when we are in complete possession of all the faculties and principles which belong to our nature.*

op

CHAPTER FIFTH.

PART SECOND.

OF THE INFLUENCE OF ASSOCIATION ON THE INTELLECTUAL AND ON THE ACTIVE POWERS.

SECTION I.

Of the Influence of casual Associations on our speculative Conclusions.

THE HE Association of Ideas has a tendency to warp our speculative opinions chiefly in the three following ways:

*See Note (0.)

First, by blending together in our apprehensions things which are really distinct in their nature; so as to introduce perplexity and error into every process of reasoning in which they are involved.

Secondly, by misleading us in those anticipations of the future from the past, which our constitution disposes us to form, and which are the great foundation of our conduct in life.

Thirdly, by connecting in the mind erroneous opinions with truths which irresistibly command our assent, and which we feel to be of importance to human happiness.

A short illustration of these remarks will throw light on the origin of various prejudices; and may, perhaps, suggest some practical hints with respect to the conduct of the understanding

I. I formerly had occasion to mention several instances of very intimate associations formed between two ideas which have no necessary connexion with each other. One of the most remarkable is that, which exists in every person's mind between the notions of colour and of extension. The former of these words expresses (at least in the sense in which we commonly employ it) a sensation in the mind; the latter denotes a quality of an external object; so that there is, in fact, no more connexion between the two notions than between those of pain and of solidity; and yet, in consequence of our always perceiving extension, at the same time at which the sensation of colour is excited in the mind, we find it impossible to think of that sensation, without conceiving extension along with it.

Another intimate association is formed in every mind between the ideas of space and of time. When we think of an interval of duration, we always conceive it as something analogous to a line, and we apply the same language to both subjects. We speak of a long and short time, as well of a long and short distance, and we are not conscious of any metaphor in doing so. Nay, so very perfect does the analogy appear to us, that Boscovich mentions it as a curious circumstance, that extension should have three dimensions, and duration only one.

This apprehended analogy seems to be founded wholly on an association between the ideas of space and of time, arising from our always measuring the one of these quantities by the other. We measure time by motion, and motion by extension. In an hour, the hand of the clock moves over a certain space; in two hours, over double the space; and so on. Hence the ideas of space and of time become very intimately united, and we apply to the latter the words long and short, before and after, in the same manner as to the former.

The apprehended analogy between the relation which the different notes in the scale of music bear to each other, and the relation of superiority and inferiority, in respect of position, among material objects, arises also from an accidental association of ideas.

What this association is founded upon, I shall not take upon me to determine, but that it is the effect of accident, appears clearly from this, that it has not only been confined to particular ages and nations, but is the very reverse of an association which was once equally prevalent. It is observed by Dr. Gregory, in the preface to his edition of Euclid's works, that the more ancient of the Greek writers looked upon

*See Note (P.)