Obrázky na stránke
PDF
ePub

to give of their meditations at the close of a long summer's day, will not be found to require many sentences. As in sleep, our communication with the external world is completely interrupted, it is not surprising that the memory of our dreams should be much more imperfect than that of our waking thoughts, even supposing us to bestow, at the moment, an equal degree of attention on both.

It is of more importance to remark, in the present argument, that those persons who are subject to Somnambulism, seldom, if ever, retain any recollection of the objects of their perceptions, while under the influence of this disorder. If the principles I have endeavoured to establish be just, this is a necessary consequence of their inattention to what then passes around them; an inattention of which nobody can doubt, who has had an opportunity of witnessing the vacant and unconscious stare which their eyes exhibit. The same fact illustrates strongly the suspension, during sleep, of those voluntary powers, to which the operations both of mind and body are at other times subjected.

These considerations derive additional evidence from a common remark, that idle people are most apt to dream, or at least, to recollect their dreams. The thoughts of the busy and of the studious are directed by their habitual occupations into a particular channel, and the spontaneous course of their ideas is checked and turned aside, by the unremitted activity of their minds. In the heedless and dissipated, the thoughts wander carelessly from object to object, according to the obvious relations of resemblance and of analogy, or of vicinity in place and time. As these are the prevailing principles of association in sleep, the chances that the dreams of such men shall be again presented to them in the course of the following day, are infinitely multiplied.

Which of these solutions approaches most nearly to the real state of the fact, I do not presume to decide. I think it probable that both of them are entitled to notice, in comparing the phenomena of dreaming with the general principles to which I have endeavoured to refer them. In cases where our dreams are occasioned by bodily sensations, or by bodily indisposition, it may be expected that the disturbed state of our rest will prevent that total cessation of the power of attention, which takes place when sleep is profound and complete ; and, in such instances, the attention which is given to our passing thoughts, may enable us afterwards to retrace them by an act of recollection. On the other hand, the more general fact unquestionably is, that at the moment of our awaking, the interval spent in sleep presents a total blank to the memory; and yet it happens not unfrequently, that, at the distance of hours, some accidental circumstance occurring to our thoughts, or suggested to us from without, revives a long train of particulars associated in the mind with each other, to which train (not being able to account otherwise for the concatenation of its parts) we give the name of a Dream.

After all, I am very far from supposing that I have exhausted this subject; and I shall be fully satisfied with the success of my inquiries, if those who are qualified to distinguish between legitimate and hypothetical theories shall admit, that I have pointed out the plan on which these phenomena should be studied, and have made some progress (how small soever) towards its execution. Much additional light, I am sensible, might have been easily thrown on this part of our constitution, as well as upon many others, if I had not imposed on myself the restraint of adhering, wherever it was at all possible, to the modes of speaking employed by my predecessors in describing our mental operations.

One remark I must beg leave to recon end to the consideration of those who may hereafter engage in this research, that among the astonishing appearances exhibited by the mind in sleep, a very large proportion are precisely analogous to those of which we are every moment conscious while awake. If the exciting causes, for example, of our dreams seem mysterious and inscrutable, is not the fact the same with the origin of every idea or thought which spontaneously solicits our notice? The only difference is, that in the latter instance, in consequence of long and constant familiarity, they are surveyed by all with little wonder, and by most with hardly any attention. In the former instance, they rouse the curiosity of the most illiterate, from their comparative infrequency, and from the contrast which, in some respects, they present to the results of our habitual experience. It is thus, that a peasant who has been accustomed from his infancy to see, without any emotion, the fall of heavy bodies to the ground, never fails to express the liveliest admiration when he first witnesses the powers of the loadstone.

In such cases, the researches of genuine science have a tendency to produce two moral effects equally beneficial. The one is to illustrate the unity of design in nature, by reconciling what seems, from its rarity or singularity, to be mysterious or incomprehensible, with the general laws which are familiarized to us by daily experience: the other, to counteract the effects of familiarity in blunting our natural curiosity with respect to these laws, by leading the thoughts to some of their more curious and apparently anomalous applications.

The phenomena of dreaming may perhaps, in this last point of view, form an article not altogether useless in the natural history of man, inasmuch as they contribute to attract our attention to those intellectual powers, from which it is so apt to be withdrawn by that external world, which affords the first, and (for the common purposes of life, the most interesting field for their exercise. In my own case, at least, this supposition has been exactly verified, as the speculations concerning the human mind which I have ventured to present to the public, all took their rise from the subject to which this note refers. The observations which I have stated with respect to it in the text (excepting a very few paragraphs since added) were written at the age of eighteen, and formed a part of the first philosophical essay which I recollect to have attempted. The same essay contained the substance of what I have introduced in chapter third, concerning the belief accompanying conception; and of the remarks stated in the third section of chapter fifth, on the extent of the power which the mind has over the train of its thoughts. When I was afterwards led professionally, at the distance of many years, to resume the same studies, this short manuscript was almost the only memorial I had preserved of these favourite pursuits of my early youth, and from the views which it recalled to me, insensibly arose the analysis I have since undertaken of our intellectual faculties in general.

For some indulgence to the egotism of this note, I must trust to the good nature of my readers. It has been lengthened much beyond my original intention, by an anxiety (not, I hope, unpardonable in an author) to fix the date of some of my disquisitions and conclusions, of which it is highly probable I may magnify the

I importance beyond their just value. The situation of a public teacher, (I must

beg leave to add,) by giving an immediate circulation to the doctrines he delivers, exposes him to many inconveniences which other classes of literary men have in their power to avoid.

Before concluding these remarks, I cannot help reminding my readers once more, that my fundamental principle with respect to the state of the mind in sleep is— not that the power of volition is then suspended, but, that the influence of the will over the faculties both of mind and body is then interrupted.—(See pp. 292-294.) I mention this chiefly, in order to mark the difference between my doctrine and that maintained in Dr. Darwin's Zoonomia. According to this ingenious writer, " the power of volition is totally suspended in perfect sleep."—(Zoonomia, vol. i. p. 315.) “In the Incubus," he observes, “the desire of moving the body is painfully exerted, but the power of moving it, or volition, is incapable of action till we awake.”—(P. 288.) Would he not have stated the fact more correctly, if he had said, that volition is painfully exerted, but that the power of moving the body is suspended ? In the very accurate phraseology of Mr. Locke," volition is an act of the mind, knowingly exerting that dominion it takes itself to have over any part of the man, by employing it in, or withholding it from, any particular action." This act of the mind Dr. Darwin expresses by the word desire, an indistinctness still extremely common among metaphysical writers, although it was long ago remarked and censured by the eminent author just quoted :—"I find," says Locke, “the will often confounded with desire, and one put for the other, and that by men who would not willingly be thought not to have very distinct notions of things, and not to have written very clearly about them."-Essay on Human Understanding, (B. ii. c. 21, $ 30.]

Note P, p. 306. – Association. (PART 11. As to Mental Habits. & 1.) Dr. Reid has, with great truth, observed that Descartes' reasonings against the existence of the secondary qualities of matter, owe all their plausibility to the ambiguity of words. When he affirms, for example, that the smell of a rose is not in the flower but in the mind, his proposition amounts only to this, that the rose is not conscious of the sensation of smell; but it does not follow from Descartes' reasonings, that there is no quality in the rose which excites the sensation of smell in the mind, which is all that any person means when he speaks of the smell of that flower: for the word smell, like the names of all secondary qualities, signifies two things, a sensation in the mind, and the unknown quality which fits it to excite that sensation. The same remark applies to that process of reasoning by which Descartes attempts to prove that there is no heat in the fire.

All this I think will be readily allowed with respect to smells and tastes, and

But if by

1 Some judicious remarks on this ambiguity in the names of Secondary Qualities, are made by Malebranche:

It is only," says he, "since the time Descartes, that those confused and indeterminate questions, whether fire is hot, grass green, and sugar sweet, philosophers are in use to answer, by distinguishing the equivocal meaning of the words expressing sensible qualities. If

by heat, cold, and savour, you understand such
and such a disposition of parts, or some un-
known motion of insensible particles, then fire
is hot, grass green, and sugar swee
heat and other qualities you understand what I
feel by fire, what I see in grass, &c., fire is not
hot, nor gruss green; for the heat I feel, and
the colours I see, are only in the soul."

also with respect to heat and cold; concerning which I agree with Dr. Reid, in thinking that Descartes' doctrine, when cleared of that air of mystery which it derives from the ambiguity of words, differs very little, if at all, from the commonly received notions. But the case seems to be different with respect to colours, of the nature of which the vulgar are apt to form a very confused conception, which the philosophy of Descartes has a tendency to correct. Dr. Reid has justly distinguished the quality of colour from what he calls the appearance of colour, which last can only exist in a mind. Now I am disposed to believe that when the vulgar speak of colour, they commonly mean the appearance of colour; or rather they associate the appearance and its cause so intimately together, that they find it impossible to think of them separately.” The sensation of colour never forms one simple object of attention to the mind like those of smell and taste, but every time we are conscious of it, we perceive at the same time extension and figure. Hence it is, that we find it impossible to conceive colour without extension, though certainly there is no more necessary connexion between them, than between extension and smell.

From this habit of associating the two together, we are led also to assign them the same place, and to conceive the different colours, or (to use Dr. Reid's language) the appearance of the different colours, as something spread over the surfaces of bodies. I own, that when we reflect on the subject with attention, we find this conception to be indistinct, and see clearly that the appearance of colour can exist only in a mind; but still it is some confused notion of this sort, which every man is disposed to form who has not been very familiarly conversant with philosophical inquiries. I find, at least, that such is tho notion which most readily presents itself to my own mind.

Nor is this reference of the sensation, or appearance of colour to an external object, a fact altogether singular in our constitution. It is extremely analogous

[ocr errors]

1 Dr. Akenside, in one of his Notes on bis Pkasures of Imagination, observes that colours, as apprehended by the mind, do not exist in the body. By this qualification, be plainly means to distinguish what Dr. Reid calls the appearance of colour, from colour considered as a quality of matter.

2 Dr. Reid is of opinion, that the vulgar always mean to express by the word colour a quality and not a sensation. “Colour," says he, "differs from other secondary qualities in this, that whereas the name of the quality is sometimes given to the sensation which indicates it, and is occasioned by it, we never, as far as I can judge, give the name of colour to the sensation, but to the quality only.” This question is of no consequence for us to discuss at present, as Dr. Reid acknowledges in the following passage, that the sensation and quality are so intimately united together in the mind, that they seem to form only one simple object of thought. “ When we think or speak of any particular colour, however simple the notion may seem to be which is presented to the ima

gination, it is really in some sort compounded; it involves an unknown cause and a known effect. The name of colour belongs indeed to the cause only, and pot to the effect. But as the cause is unknown, we can form no distinct conception of it, but by its relation to the known effect. And therefore both go together in the imagination, and are so closely united that they are mistaken for one simple object of thought." - Inquiry into the Human Mind, chap. vi. sect. 4.

(These two positions of Dr. Reid's do not appear to me quite consistent with each other. " If, in the perception of colour, the sensation and the quality be so closely united as to be mistaken for one simple object of thought," dves it not obviously follow, that it is to this compounded notion the name of colour must in general be given ? On the other hand, when it is said, that “the name of colour is never given to the sensation but to the quality only," does not this imply that every time the word is pronounced, the quality is separated from the sensation, even in the imaginations of the vulgar!)

to the reference which we always make, of the sensations of touch to those parts of the body where the exciting causes of the sensations exist. If I strike my hand against a hard object, I naturally say, that I feel pain in my hand. The philosophical truth is, that I perceive the cause of the pain to be applied to that part of my body. The sensation itself I cannot refer in point of place to the hand, without conceiving the soul to be spread over the body by diffusion.

A still more striking analogy to the fact under our consideration, occurs in those sensations of touch which we refer to a place beyond the limi s of the body, as in the case of pain felt in an amputated limb.

The very intimate combination to which the foregoing observations on the sensation of colour relate, is taken notice of by D'Alembert in the Encyclopedia, as one of the most curious phenomena of the human mind.

“Il est très évident que le mot couleur ne désigne aucune propriété du corps, mais seulement une modification de notre âme ; que la blancheur, par exemple, la rougeur, &c., n'existent que dans nous, et nullement dans le corps ausquels nous les rapportons ; néanmoins par une habitude prise dès notre enfance, c'est une chose très singulière et digne de l'attention des métaphysiciens, que ce penchant que nous avons à rapporter à une substance matérielle et divisible, ce qui appartient réellement à une substance spirituelle et simple ; et rien n'est peut-être plus extraorılinaire dans les operations de notre âme, que de la voir transporter hors d'elle-même et étendre, pour ainsi dire, ses sensations sur une substance à laquelle elles ne peuvent appartenir.”

From the following passage in Condillac's Traité des Sensations, it appears that the phenomenon here remarked by D'Alembert, was, in Condillac's opinion, the natural and obvious effect of an early and habitual association of ideas. I quote it with the greater pleasure, that it contains the happiest illustration I have seen of the doctrine which I have been attempting to explain.

" On pourroit faire une supposition, où l'odorat apprendroit à juger parfaitement des grandeurs, des figures, des situations, et des distances. Il suffiroit d'un côté de soumettre les corpuscules odoriférans aux loix de la dioptrique, et de l'autre, de construire l'organe de l'odorat à peu près sur le modèle de celui de la vûe ; ensorte que les rayons odoriférans, après s'être croisés à l'ouverture, frappassent sur une mem! intérieure autant de points distincts qu'il y en a sur les surfaces d'où ils seroient réfléchis.

" En pareil cas, nous contracterisons bientôt l'habitude d'étendre les odeurs sur les objets, et les philosophes ne manqueroient pas de dire, que l'odorat n'a pas besoin des leçons du toucher pour appercevoir des grandeurs et des figures."Euvres de Condillac, Edit. Amst. vol. v. p. 223.

[The very same illustration is to be found in Reid's Inquiry, chap. vi. sect. 8. ('ondillac, however, has an unquestionable claim to it, in point of priority, although I have not the smallest doubt that it occurred to Reid in the course of his own speculations. Indeed, I have good ground for thinking he was not at all acquainted with Condillac's writings.]

Note Q; p. 307.- Association. (PART 11. As to Mental Habits. $ 2.) “ Verum quidem est, quod hodierni musici sic loqui soleant (acutum in alto repiltantes et grave in imo) quodque ex Græcis recentioribus nonnulli sic aliquando (sed VOL. 11.

21

« PredošláPokračovať »