[14] In a letter to Hutcheson (September 17th, 1739) Hume remarks:--"There are different ways of examining the mind as well as the body. One may consider it either as an anatomist or as a painter: either to discover its most secret springs and principles, or to describe the grace and beauty of its actions;" and he proceeds to justify his own mode of looking at the moral sentiments from the anatomist's point of view.

[15] The manner in which Hume constantly refers to the results of the observation of the contents and the processes of his own mind clearly shows that he has here inadvertently overstated the case.

[16] Locke, _An Essay concerning Human Understanding_, Book I, chap. i, ---- 4, 5, 6.

[17] _Kritik der reinen Vernunft._ Ed. Hartenstein, p. 256.

CHAPTER II.

THE CONTENTS OF THE MIND.

In the language of common life, the "mind" is spoken of as an ent.i.ty, independent of the body, though resident in and closely connected with it, and endowed with numerous "faculties," such as sensibility, understanding, memory, volition, which stand in the same relation to the mind as the organs do to the body, and perform the functions of feeling, reasoning, remembering, and willing. Of these functions, some, such as sensation, are supposed to be merely pa.s.sive--that is, they are called into existence by impressions, made upon the sensitive faculty by a material world of real objects, of which our sensations are supposed to give us pictures; others, such as the memory and the reasoning faculty, are considered to be partly pa.s.sive and partly active; while volition is held to be potentially, if not always actually, a spontaneous activity.

The popular cla.s.sification and terminology of the phenomena of consciousness, however, are by no means the first crude conceptions suggested by common sense, but rather a legacy, and, in many respects, a sufficiently _d.a.m.nosa haereditas_, of ancient philosophy, more or less leavened by theology; which has incorporated itself with the common thought of later times, as the vices of the aristocracy of one age become those of the mob in the next. Very little attention to what pa.s.ses in the mind is sufficient to show, that these conceptions involve a.s.sumptions of an extremely hypothetical character. And the first business of the student of psychology is to get rid of such prepossessions; to form conceptions of mental phenomena as they are given us by observation, without any hypothetical admixture, or with only so much as is definitely recognised and held subject to confirmation or otherwise; to cla.s.sify these phenomena according to their clearly recognisable characters; and to adopt a nomenclature which suggests nothing beyond the results of observation. Thus chastened, observation of the mind makes us acquainted with nothing but certain events, facts, or phenomena (whichever name be preferred) which pa.s.s over the inward field of view in rapid and, as it may appear on careless inspection, in disorderly succession, like the shifting patterns of a kaleidoscope. To all these mental phenomena, or states of our consciousness,[18] Descartes gave the name of "thoughts,"[19] while Locke and Berkeley termed them "ideas." Hume, regarding this as an improper use of the word "idea," for which he proposes another employment, gives the general name of "perceptions" to all states of consciousness. Thus, whatever other signification we may see reason to attach to the word "mind," it is certain that it is a name which is employed to denote a series of perceptions; just as the word "tune,"

whatever else it may mean, denotes, in the first place, a succession of musical notes. Hume, indeed, goes further than others when he says that--

"What we call a mind is nothing but a heap or collection of different perceptions, united together by certain relations, and supposed, though falsely, to be endowed with a perfect simplicity and ident.i.ty."--(I. p. 268.)

With this "nothing but," however, he obviously falls into the primal and perennial error of philosophical speculators--dogmatising from negative arguments. He may be right or wrong; but the most he, or anybody else, can prove in favour of his conclusion is, that we know nothing more of the mind than that it is a series of perceptions. Whether there is something in the mind that lies beyond the reach of observation; or whether perceptions themselves are the products of something which can be observed and which is not mind; are questions which can in nowise be settled by direct observation. Elsewhere, the objectionable hypothetical element of the definition of mind is less prominent:--

"The true idea of the human mind is to consider it as a system of different perceptions, or different existences, which are linked together by the relation of cause and effect, and mutually produce, destroy, influence and modify each other.... In this respect I cannot compare the soul more properly to anything than a republic or commonwealth, in which the several members are united by the reciprocal ties of government and subordination, and give rise to other persons who propagate the same republic in the incessant changes of its parts."--(I. p. 331).

But, leaving the question of the proper definition of mind open for the present, it is further a matter of direct observation, that, when we take a general survey of all our perceptions or states of consciousness, they naturally fall into sundry groups or cla.s.ses. Of these cla.s.ses, two are distinguished by Hume as of primary importance. All "perceptions,"

he says, are either "_Impressions_" or "_Ideas_."

Under "impressions" he includes "all our more lively perceptions, when we hear, see, feel, love, or will;" in other words, "all our sensations, pa.s.sions, and emotions, as they make their first appearance in the soul"

(I. p. 15).

"Ideas," on the other hand, are the faint images of impressions in thinking and reasoning, or of antecedent ideas.

Both impressions and ideas may be either _simple_, when they are incapable of further a.n.a.lysis, or _complex_, when they may be resolved into simpler const.i.tuents. All simple ideas are exact copies of impressions; but, in complex ideas, the arrangement of simple const.i.tuents may be different from that of the impressions of which those simple ideas are copies.

Thus the colours red and blue and the odour of a rose, are simple impressions; while the ideas of blue, of red, and of rose-odour are simple copies of these impressions. But a red rose gives us a complex impression, capable of resolution into the simple impressions of red colour, rose-scent, and numerous others; and we may have a complex idea, which is an accurate, though faint, copy of this complex impression.

Once in possession of the ideas of a red rose and of the colour blue, we may, in imagination, subst.i.tute blue for red; and thus obtain a complex idea of a blue rose, which is not an actual copy of any complex impression, though all its elements are such copies.

Hume has been criticised for making the distinction of impressions and ideas to depend upon their relative strength or vivacity. Yet it would be hard to point out any other character by which the things signified can be distinguished. Any one who has paid attention to the curious subject of what are called "subjective sensations" will be familiar with examples of the extreme difficulty which sometimes attends the discrimination of ideas of sensation from impressions of sensation, when the ideas are very vivid, or the impressions are faint. Who has not "fancied" he heard a noise; or has not explained inattention to a real sound by saying, "I thought it was nothing but my fancy"? Even healthy persons are much more liable to both visual and auditory spectra--that is, ideas of vision and sound so vivid that they are taken for new impressions--than is commonly supposed; and, in some diseased states, ideas of sensible objects may a.s.sume all the vividness of reality.

If ideas are nothing but copies of impressions, arranged, either in the same order as that of the impressions from which they are derived, or in a different order, it follows that the ultimate a.n.a.lysis of the contents of the mind turns upon that of the impressions. According to Hume, these are of two kinds: either they are impressions of sensation, or they are impressions of reflection. The former are those afforded by the five senses, together with pleasure and pain. The latter are the pa.s.sions or the emotions (which Hume employs as equivalent terms). Thus the elementary states of consciousness, the raw materials of knowledge, so to speak, are either sensations or emotions; and whatever we discover in the mind, beyond these elementary states of consciousness, results from the combinations and the metamorphoses which they undergo.

It is not a little strange that a thinker of Hume's capacity should have been satisfied with the results of a psychological a.n.a.lysis which regards some obvious compounds as elements, while it omits altogether a most important cla.s.s of elementary states.

With respect to the former point, Spinoza's masterly examination of the Pa.s.sions in the third part of the _Ethics_ should have been known to Hume.[20] But, if he had been acquainted with that wonderful piece of psychological anatomy, he would have learned that the emotions and pa.s.sions are all complex states, arising from the close a.s.sociation of ideas of pleasure or pain with other ideas; and, indeed, without going to Spinoza, his own acute discussion of the pa.s.sions leads to the same result,[21] and is wholly inconsistent with his cla.s.sification of those mental states among the primary uncompounded materials of consciousness.

If Hume's "impressions of reflection" are excluded from among the primary elements of consciousness, nothing is left but the impressions afforded by the five senses, with pleasure and pain. Putting aside the muscular sense, which had not come into view in Hume's time, the questions arise whether these are all the simple undecomposable materials of thought? or whether others exist of which Hume takes no cognizance.

Kant answered the latter question in the affirmative, in the _Kritik der reinen Vernunft_, and thereby made one of the greatest advances ever effected in philosophy; though it must be confessed that the German philosopher's exposition of his views is so perplexed in style, so burdened with the weight of a c.u.mbrous and uncouth scholasticism, that it is easy to confound the unessential parts of his system with those which are of profound importance. His baggage train is bigger than his army, and the student who attacks him is too often led to suspect he has won a position when he has only captured a mob of useless camp-followers.

In his _Principles of Psychology_, Mr. Herbert Spencer appears to me to have brought out the essential truth which underlies Kant's doctrine in a far clearer manner than any one else; but, for the purpose of the present summary view of Hume's philosophy, it must suffice if I state the matter in my own way, giving the broad outlines, without entering into the details of a large and difficult discussion.

When a red light flashes across the field of vision, there arises in the mind an "impression of sensation"--which we call red. It appears to me that this sensation, red, is a something which may exist altogether independently of any other impression, or idea, as an individual existence. It is perfectly conceivable that a sentient being should have no sense but vision, and that he should have spent his existence in absolute darkness, with the exception of one solitary flash of red light. That momentary illumination would suffice to give him the impression under consideration; and the whole content of his consciousness might be that impression; and, if he were endowed with memory, its idea.

Such being the state of affairs, suppose a second flash of red light to follow the first. If there were no memory of the latter, the state of the mind on the second occasion would simply be a repet.i.tion of that which occurred before. There would be merely another impression.

But suppose memory to exist, and that an idea of the first impression is generated; then, if the supposed sentient being were like ourselves, there might arise in his mind two altogether new impressions. The one is the feeling of the _succession_ of the two impressions, the other is the feeling of their _similarity_.

Yet a third case is conceivable. Suppose two flashes of red light to occur together, then a third feeling might arise which is neither succession nor similarity, but that which we call _co-existence_.

These feelings, or their contraries, are the foundation of everything that we call a relation. They are no more capable of being described than sensations are; and, as it appears to me, they are as little susceptible of a.n.a.lysis into simpler elements. Like simple tastes and smells, or feelings of pleasure and pain, they are ultimate irresolvable facts of conscious experience; and, if we follow the principle of Hume's nomenclature, they must be called _impressions of relation_. But it must be remembered, that they differ from the other impressions, in requiring the pre-existence of at least two of the latter. Though devoid of the slightest resemblance to the other impressions, they are, in a manner, generated by them. In fact, we may regard them as a kind of impressions of impressions; or as the sensations of an inner sense, which takes cognizance of the materials furnished to it by the outer senses.

Hume failed as completely as his predecessors had done to recognise the elementary character of impressions of relation; and, when he discusses relations, he falls into a chaos of confusion and self-contradiction.

In the _Treatise_, for example, (Book I., -- iv.) resemblance, contiguity in time and s.p.a.ce, and cause and effect, are said to be the "uniting principles among ideas," "the bond of union" or "a.s.sociating quality by which one idea naturally introduces another." Hume affirms that--

"These qualities produce an a.s.sociation among ideas, and upon the appearance of one idea naturally introduce another." They are "the principles of union or cohesion among our simple ideas, and, in the imagination, supply the place of that inseparable connection by which they are united in our memory. Here is a kind of _attraction_, which, in the mental world, will be found to have as extraordinary effects as in the natural, and to show itself in as many and as various forms. Its effects are everywhere conspicuous; but, as to its causes they are mostly unknown, and must be resolved into _original_ qualities of human nature, which I pretend not to explain."--(I. p. 29.)

And at the end of this section Hume goes on to say--

"Amongst the effects of this union or a.s.sociation of ideas, there are none more remarkable than those complex ideas which are the common subjects of our thought and reasoning, and generally arise from some principle of union among our simple ideas. These complex ideas may be resolved into _relations_, _modes_, and _substances_."--(_Ibid._)

In the next section, which is devoted to _Relations_, they are spoken of as qualities "by which two ideas are connected together in the imagination," or "which make objects admit of comparison," and seven kinds of relation are enumerated, namely, _resemblance_, _ident.i.ty_, _s.p.a.ce and time_, _quant.i.ty or number_, _degrees of quality_, _contrariety_, and _cause and effect_.

To the reader of Hume, whose conceptions are usually so clear, definite, and consistent, it is as unsatisfactory as it is surprising to meet with so much questionable and obscure phraseology in a small s.p.a.ce. One and the same thing, for example, resemblance, is first called a "quality of an idea," and secondly a "complex idea." Surely it cannot be both. Ideas which have the qualities of "resemblance, contiguity, and cause and effect," are said to "attract one another" (save the mark!), and so become a.s.sociated; though, in a subsequent part of the _Treatise_, Hume's great effort is to prove that the relation of cause and effect is a particular case of the process of a.s.sociation; that is to say, is a result of the process of which it is supposed to be the cause. Moreover, since, as Hume is never weary of reminding his readers, there is nothing in ideas save copies of impressions, the qualities of resemblance, contiguity, and so on, in the idea, must have existed in the impression of which that idea is a copy; and therefore they must be either sensations or emotions--from both of which cla.s.ses they are excluded.

In fact, in one place, Hume himself has an insight into the real nature of relations. Speaking of equality, in the sense of a relation of quant.i.ty, he says--

"Since equality is a relation, it is not, strictly speaking, a property in the figures themselves, but arises merely from the comparison which the mind makes between them."--(I. p. 70.)

That is to say, when two impressions of equal figures are present, there arises in the mind a _tertium quid_, which is the perception of equality. On his own principles, Hume should therefore have placed this "perception" among the ideas of reflection. However, as we have seen, he expressly excludes everything but the emotions and the pa.s.sions from this group.

It is necessary therefore to amend Hume's primary "geography of the mind" by the excision of one territory and the addition of another; and the elementary states of consciousness will stand thus:--

A. IMPRESSIONS.

A. Sensations of _a._ Smell.

_b._ Taste.

_c._ Hearing.

_d._ Sight.

_e._ Touch.

_f._ Resistance (the muscular sense).

B. Pleasure and Pain.

C. Relations.

_a._ Co-existence.

_b._ Succession.

_c._ Similarity and dissimilarity.

B. IDEAS.