Now so long as we state facts o£ which all the terms lie? within the organism, our facts are morphological or physiological and in no degree psychological. Even though the relation with which we are dealing is that between a change and a feeling, it is still not a psychological relation so long as the feeling is regarded merely as connected with the nervous change, and not as connected with some existence lying outside the organism. As certainly as the man who demonstrates by dissection the articulations of the bones, and the man who, by a sphygmograph, delineates the varying motions of the heart, are respectively studying morphology and physiology; so certainly is the man who examines nervous structure and experiments on nervous function, a student of these same sciences,, if he considers the inner correlations only and does not simultaneously consider the answering outer correlations.
For that which distinguishes Psychology from the sciences on which it rests,, is, that each of its propositions takes account both of the connected internal phenomena and of the connected external phenomena to which they refer. In a physiological proposition an inner relation is the essential subject of thought; but in a psychological proposition an outer relation is joined with it as a co-essential subject of thought. A relation in the environment rises into co-ordinate importance with a relation in the organism. The thing contemplated is now a totally different thing. It is not the connection between the internal phenomena, nor is it the connection between the external phenomena; but it is the connection between these two connections. A psychological proposition is necessarily compounded of two propositions, of which one concerns the subject and the other concerns the object; and cannot be expressed without the four terms which these two propositions imply. The distinction may be best explained by symbols. Suppose that A and B are two related manifestations in the environment — say,, the colour and taste of a fruit; then, so long as we contemplate their relation by itself, or as associated with other external phenomena, we are occupied with a portion of physical science. Isow suppose that a and b are the sensations produced in the organism by this peculiar light which the fruit reflects, and by tlie cliemical action of its juice on tlio palate \ then, so long as we study the action of the light on the retina and optic centres, and consider how the juice sets up in other centres a nervous change known as sweetness, we are occupied with facts belonging to the sciences of Physiology and JEstho-physiology. Bat we pass into the domain of Psychology the moment we inquire how there comes to exist within the organism a relation between a and b that in some way or other corresponds to the relation between A and B. Pyschology is exclusively concerned with this connection between (A B) and (a 6) — has to investigate its nature, its origin, its meaning, &c.
A moment's introspection will now make it clear to the reader, that he cannot frame any psychological conception without thus looking at internal co-existences and sequences in their adjustments to external co-existences and sequences. If he studies the simplest act of perception, as that of localizing a touch in some part of IPS skin, the indispensable terms of his inquiry are: — on the one hand a thing (1) and a position (2), both of which he regards as objective; and on the other hand a sensation (3), and a state of consciousness constituting his apprehension of position (4), both of which he regards as subjective. Again, to cite an example from the opposite extreme, if he takes for his problem one of his involved sentiments, as that of justice, he cannot represent to himself this sentiment, or give any meaning to its name, without calling to mind actions and relations supposed to exist in the environment: neither this nor any other emotion can be aroused in consciousness even vaguely, without positing something beyond consciousness to which it refers. And when, instead of studying Psychology subjectively, he studies it objectively in the acts of other beings, he similarly finds himself incapable of stirring a step without thinking of inner correlations in their references to outer correlations.
]<3t THE DATA OF PSYCHOLOGY.
§ 54. It is contended by some that Psychology is a part of Biology, and should be merged in it; and those who hold this view will possibly answer the above argument by saying that in many cases the non-psychological part of Biology also takes into account phenomena in the environment^ and even definite connections among these phenomena. The life of every organism is a continuous adaptation of its inner actions to outer actions; and a complete interpretation of the inner actions involves recognition of the outer actions. The annual production of leaves, flowers, and seeds by plants, is adjusted to the annual changes of the seasons; and there is in animals an adjustment between external changes in temperature and abundance, and internal production of ova. Moreover, there are many special relations of structure and function in plants and animals, that have reference to special relations of structure and function in surrounding plants and animals: instance those arrangements of the sexual organs that fit particular phsenoganis for being fertilized by the particular insects that visit them.
But ferae as is this conception of Life (and having based the Principles of Biology on it I am not likely to question or to undervalue it), I nevertheless hold the distinction above drawn to be substantially valid. For throughout Biology proper, the environment and its correlated phenomena are either but tacitly recognized, or, if overtly and definitely recognized, are so but occasionally; while the organism and its correlated phenomena practically monopolize the attention. But in Psychology, the correlated phenomena of the environment are at every step avowedly and distinctly recognized; and are as essential to every psychological idea as are the correlated phenomena of the organism. Let us observe the contrast as exemplified.. We study digestion. Digestion implies food. Food implies neighbouring plants or animals. But this implication scarcely enters into our study of digestion, THE SCOFE OF PSYCHOLOGY. 135 unless we ask the quite special question — liow the digestive organs become fitted to the materials they have to act upon? Again, when we interpret respiration we take for granted a surrounding oxygenated medium. And yet to show how far the two may be separated, we need only remember that the phenomena of respiration may be very well traced out in one who breathes a bladder of gas artificially obtained from peroxide of manganese or chlorate of potash. Once more, if, in following out the life-history of a plant, we have to note the adaptation of its hooked seeds to the woolly fleece of the animal which accidentally carries them, off and disperses them, this distinct reference to specially- connected phenomena in the environment, occurs either but once in an account of the plant's life, or only at long intervals. In fact, we may say that the great mass of purely biological phenomena may be displayed for some time by an organism detached from its medium, as by a fish out of water. Now observe how different it is with psychological phenomena. We cannot explain a single act of a fish as it moves about in the water,, without taking into account its relations to neighbouring -objects distinguished by specially-related attributes. The instinctive proceedings of the insect, equally with those which in higher creatures we call intelligent, we are unable even to express without referring to things around.
In brief, then, the propositions of Biology, when they imply the environment at all, imply almost exclusively its few general and constant phenomena, which, because of their generality and constancy, may be left out of consideration; whereas the propositions of Psychology refer to its multitudinous, special, and ever- varying phenomena, which, because of their speciality and changeability, cannot be left out of consideration.
§ 55. The admission that Psychology is not demarcated; from Biology by a sharp line, will perhaps be construed; into tie admission that it cannot rightly be regarded as a * distinct science. But those who so construe the admission, misconceive the natures of the relations among the sciences. They assume that there exist objectively those clear separations which the needs of classification lead us to make.subjectively. Whereas the fact is, that beyond the divisions between the three fundamental orders of the sciences, Abstract, Abstract-concrete, and Concrete, there exist ob-^ jec lively no clear separations at all: there are only differ- ;. ent groups of phenomena broadly contrasted but shading " off one into another. To those who accept the doctrine of Evolution, this scarcely needs saying; for Evolution being a universal process, one and continuous throughout all forms of existence, there can be no break — no change from one group of concrete phenomena to another without a bridge of intermediate phenomena. It will be well here, 3 however, to show by illustrations that the simpler concrete sciences are separable from one another only in the same I way that Psychology is separable from Biology.
* Astronomy and Geology are regarded as distinct. But I Geology is nothing more than a chapter continuing in i detail one part of a history that was once wholly astrono- I mic; and even now, many of its leading facts belong as I much to the older part of the history as to the younger.
[ Not only do we trace back the Earth to a time when its ' astronomic attributes were uncomplicated by those geoj logic ones that have gradually arisen as it cooled; not only ,, in the solar heat, causing the aerial, marine, and fluvial i 4 currents which work most geologic changes, are we compelled to recognize an astronomic force; but in the tidal wave we have a phenomenon as much astronomic as geologic, and as much geologic as astronomic. Even he who arbitrarily excludes from astronomy everything but the molar motions throughout the Solar System (so ignoring the radiant light and heat by which alone the Sun and planets are known to us) does not escape this difficulty; for the motion of the tidal wave is a molar motion generated by forces such as generate all other molar motions exhibited by the Solar System; and yet it is at the same time a motion of matter on the Earth's surface,, not distinguishable from those other motions of matter which constitute geological changes, many of which, indeed, are concomitants of it. The separation between Biology and Geology once seemed impassable; and to many seems so now. But every day brings new reasons for believing that the one group of phenomena has grown out of the other. Organisms are highly-diflerentiated portions of the matter forming the Earth's crust and its gaseous envelope; and their differentiation from the rest has arisen, like other differentiations, by degrees. The chasm between the inorganic and the organic is being filled up. On the one hand, some four or five thousand compounds once regarded as exclusively organic, have now been produced artificially from inorganic matter; and chemists do not doubt their ability so to produce the highest forms of organic matter. On the other hand, the microscope has traced down organisms to simpler and simpler forms until, in the Protogenes of Professor HaeckeL, there has been reached a type distinguishable from a fragment of albumen only by its finely-granular character.
Thus the distinction between Biology and Psychology has the same justification as the distinctions between the concrete sciences below them. Theoretically, all the concrete sciences are adjoining tracts of one science, which has for; its subject-matter, the continuous transformation which the Universe undergoes. Practically, however, they are distinguishable as successively more specialized parts of the? total science — parts further specialized by the introduction \ of additional factors. The Astronomy of the Solar System is a specialized part of that general Astronomy which includes oar whole Sidereal System; and becomes specialized by taking into account the revolutions and rotations of planets IS8 THE DATA OF PSYCHOLOGY.
and satellites. Geology (or rather Geogeny let us call ifc, that we may include all those mineralogical and meteorological changes which the word Geology, as now used, recognizes but tacitly) is a specialized part of this special Astronomy; and becomes specialized by joining with the effects of the Earth's molar motions,, the effects of continuous decrease in its internal molecular motion, and the effects of the molecular motion radiated from the Sun. Biology is a specialized part of Geogeny, dealing with peculiar aggregates of peculiar chemical compounds formed of the Earth's superficial elements— aggregates which, while exposed to these same general forces molar and molecular, also exert certain general actions and reactions on one another. And Psychology is a specialized part of Biology, limited in its application to the higher division of these peculiar aggregates, and occupying itself exclusively with those special actions and reactions which they display, from instant to instant, in their converse with the special objects, animate and inanimate, amid which they move.
But this introduction of additional factors, which differentiates each more special science from the more general science including it, fails in every case to differentiate it absolutely -} because the introduction of -the additional factors is gradual. It is so not with the Concrete Sciences alone, but even with the Abstract-concrete Sciences, which at first sight seem sharply demarcated; as, for instance, Physics and Chemistry. Physics, dealing with changes in the distribution of matter and motion considered apart from, unlikenesses of quality in the matter, is obliged to include in its inquiries all the molecular integrations and disintegrations caused by alterations of temperature — the meltings and evaporations which increase of heat produces, as well as the condensations and crystallizations which follow decrease of heat. Among other molecular transformations resulting from losses and gains of molecular motion, are those known as allo tropic — transformations which, without appreciably altering the degrees of integration, leave the molecules so re-arranged that they exhibit new properties of the order we call chemical; as is shown by their changed affinities for the molecules of other substances, and by their changed effects on our nerves of sense. Must we class such molecular transformations as physical phenomena,, because in each case the molecules concerned are all of one kind? If so, what are we to say of isomeric transformations, which all chemists recognize as of essentially the same nature? In these, molecules of different kinds are concerned. And if, because they show us a re- distribution of heterogeneous molecules instead of homogeneous ones, we put them in the category of chemical phenomena, we arbitrarily dissociate two fundamentally-similar classes of facts. Perhaps it will be replied that in isomeric transformations the molecules art} homogeneous, relatively to the re-distribution they undergo; that each of them, retaining its individuality unchanged, comports itself towards the rest as though it were a simple molecule; that nothing more takes place than a re-grouping of these unchanged molecules; and that there is thus an absence of what constitutes a truly chemical change — union or disunion of unlike molecules. The reply is plausible,, but it is easily disposed of. For there are transformations of this nature in which such unions and disunions occur. A colloid compound in passing from one of its isomeric forms to another, very generally parts with some of its contained water, or takes up additional water. Does this make the change a chemical one? Then we must relegate to the domain of Physics that isotnerism which is not accompanied by loss or gain of water, and include in the domain of Chemistry that isomerisrn which is so accompanied — a very artificial disunion of the sciences, to which I think neither Physicists nor Chemists will agree. Nevertheless, undecided as is the line winch separates them, we are not prevented from recognizing the broad distinction between. Molecular Physics and Chemistry. The new factor which.
liO THE DATA OP PSYCHOLOGY.
differentiates Chemistry from Molecular Physics, is the heterogeneity of the molecules with whose re- distribution^ it deals. And the contrast hence resulting is too strongly marked to be obliterated by transitional cases.
In this way it is, then, that the conspicuous presence of additional factors differentiates Psychology from Biology proper; although in Biology proper these factors make an occasional appearance. The contrast between the two is no more destroyed by such community as exists, than is the contrast between night and day destroyed by the occurrence of a dawn which belongs as much to one as to the other.
§ 56. A far more radical distinction remains to be drawn. While, under its objective aspect, Psychology is to be classed as one of the concrete sciences which successively decrease in scope as they increase in speciality; under its subjective aspect, Psychology is a totally unique science, independent of, and antithetically opposed to, all other sciences whatever. The thoughts and feelings which constitute a consciousness, and are absolutely inaccessible to any but the possessor of that consciousness, form an existence that has no place among the existences with which the rest of the sciences * deal. Though accumulated observations and experiments; have led us by a very indirect series of inferences (§ 41) to the belief that mind and nervous action are the subjective and objective faces of the same thing, we remain utterly incapable of seeing, and even of imagining, how the two are related. Mind still continues to us a something without any kinship to other things; and from the science which discovers by introspection the laws of this something, there is no passage, by transitional steps to the sciences which discover the law.-of these other things. ' Following M. Comte, there are a few who assert that a subjective Psychology is impossible; and to such the above I paragraph will, I suppose, be meaningless. But whoever I recognizes a subjective Psychology., and admits, as he must, THE SCOPE OF PSYCHOLOGY. ]41 that without it there can be no objective Psychology, there--upon finds himself obliged to assign a quite special rank, not to the first only, but., by implication,, to the second. To those who see that the essential conceptions on which Psychology in general proceeds, are furnished by subjective Psychology — to those who see that such words as feelings, ideas, memories, volitions, have acquired their several meanings through self-analysis, and that the distinctions we make between sensations and emotions, or between automatic acts and voluntary acts, can be established only by comparisons among, and classifications of, our mental states; it will be manifest that objective Psychology can have no existence as such, without borrowing its data from subjective Psychology. And thus perceiving that, until it--acknowledges its indebtedness to subjective Psychology, objective Psychology cannot legitimately use any terms that imply consciousness, but must limit itself to nervous coordinations considered as physical only; they will see that even objective Psychology contains an element which differentiates it from the rest of the special concrete sciences more than any of these are differentiated from one another.
The claims of Psychology to rank as a distinct science, f are thus not smaller but greater than those of any other! science. If its phenomena are contemplated objectively,! merely as nervo -muscular adjustments by which the higher1 organisms from moment to moment adapt their actions to environing co-existences and sequences, f its degree of speciality, even then, entitles it to a separate place. The moment the element of feeling, or consciousness, is used to interpret nervo-muscular adjustments as thus exhibited in the living beings around, objective Psychology acquires an additional, and quite exceptional, distinction. And it is, further distinguished in being linked by this common element of consciousness, to the totally-independent science; of subjective Psychology — the two forming together a double science which, as a whole, is quite sui generis.
^.-> THE DATA OF PSYCHOLOGY.
§ 57. So understanding its scope, we are now prepared to enter on the study of Psychology proper. The foregoing discussion serves not unfitly to introduce the several divisions into which the entire subject falls.
First come the Inductions of Psychology; under which title we will deal with the leading empirical generalizations presenting them,, however, under an aspect somewhat different from the usual one. And the truths inductively reached will, when possible, be elucidated deductively, by affiliating them., on the truths of Neuro-physiology and zEstho-physiology set down in the foregoing chapters.
We will next pass to Objective Psychology; of which three divisions may conveniently be made. Tn the first, or General Synthesis, we will trace throughout the animal kingdom, the progress in these perpetual ^adjustments of special Jnner actions to special outer actions, which accompanies increasing evolution of the nervous system — omitting, so far as may be, the element of consciousness. In the second, or Special Synthesis, we will consider this same progress more closely, with the view of delineating and formulating it in terms that imply consciousness. And in the third, or Physical Synthesis, an endeavour will be made to show how, by an ultimate principle of nervous action, this progress is explicable as part of Evolution, in general.
Turning then to Subjective Psychology, the natures of particular modes of consciousness, as ascertained by introspection, will first be treated under the head of Special Analysis. And then, under the head of General.Analysis, we will enter upon the ultimate question of the relation between Thought and Things.
Two remaining divisions will be devoted, the one to a comparison between the results reached in the preceding divisions, with a view of showing their cougruity, and the other to a series of corollaries constituting that special part of Human Psychology on which Sociology must be based.
PART II.
CHAPTER I.
§ 58. To write a chapter for tlie purpose of stowing tliat nothing is known, or can be known, of the subject which tlie title of the chapter indicates,, will be thought strange. It is, however, in this case needful — needful because, in the absence of explanation, much that has gone before, and much that will come hereafter, may be misinterpreted; and needful also because we have to distinguish between that absolute ignorance and that partial knowledge which may be asserted according as we give one or other meaning to the terms used.
For if by the phrase " su^tancejol^Mm^*' is to be under-; stood Mind as qualitatively differentiated in each portion that is separable by introspection but seems homogeneous and undecomposable; then we do know something about the substance of Mind, and may eventually know more. Assuming**^ an underlying something, it is possible in some cases to see, / and in the rest to conceive, how these multitudinous modifi- ( cations of it arise. But if tne phrase is taken to mean the JfL underlying something of which these distinguishable portions L are formed, 'or of which they are modifications; thgp. we > know nothing about it, and never can know,. Anything about' iL_ It is not enough to say that such knowledge is beyond the grasp of human intelligence as it now esists; for jno amount of that which wejsall intelligence, however transcSadent, cmjg^sj^ These two propositions will need a good deal of elucidation. It will be most convenient to deal first with the last § 59. To meet all imaginable possibilities,, let us set out with the doctrine of Hume, that impressions and ideas are tlie only tilings known to exist,, and that Mind is merely a name for the sum of them. In this case, the expression " substance of Mind" can have no meaning, unless as applied to each or any impression or idea individually. Whence it follows that there are as many different substances of Mind as there are different impressions and ideas; and this amounts to the conclusion that there is no substance of Mind in the sense implied; or, at any rate, that we have no evidence of irs existence. A fortiori, the substance of Mind cannot be known.
Contrariwise, let us yield to the necessity of regarding impressions and ideas as forms or modes of a continuallyexisting something. Failing in every effort to break the series of impressions and ideas in two, we are prevented from thinking of them as separate existences. While each particular impression or idea can be absent,, that which holds impressions and ideas together is never absent; and its unceasing presence necessitates, or indeed constitutes, the notion of continuous existence or reality. .Existence means nothing more than persistence; and thence in Mind that which persists in spite of all f changes/ and maintains the unity of the aggregate in defiance of all attempts to divide it, is that of which existence in the full sense of the word mus? be predicated— that which we must postulate as the substance of Mind in 3pntradistinctipn to the varying forms ^assumes. But if so, the impossibility of knowing fhe"" substance of Mind is manifest. By the definition, it is that which under, goes the modification producing a state of Mind. Consequently, if every staie of Mind is some modification of tliis substance of Mind, there can be no state of mind in which the unmodified substance of Mind is present.
Knowing implies something acted upon and something acting upon it. To see that this is undeniable we have but to glance at the three intelligible propositions which can alone be framed respecting the ultimate character of cognition. Suppose the thing presented in consciousness persists unchanged; then,, as in the absence of change there is 110 consciousness, there can be no knowledge. Suppose there follows something which has no determinate relation whatever to its antecedent; then, the change being wholly indeterminate, there is no knowledge, since knowledge is the establishment in thought of determinate relations. Suppose lastly, that the succeeding something has a determinate relation to that which precedes it; then the implication is that the two are linked (if they are not, any other thing may equally well follow) • and to think of a special thing (existing) as linked with a special thing (about to exist) is to think of the second as having a speciality resulting from the co-operation of the first and something else. So that be the thing contemplated in the act of cognition a symbolized' activity existing beyond the Mind, or be it a past state of Mind itself, that which contemplates it is distinct from it.
Hence were it possible for the substance of Mind to be present in any state of Mind, there would still have to be answered the question — What is it which then contemplates it and knows it? That which in the act of knowing is affected by the thing known, must itself be the substance of Mind, The substance of Mind escapes into some new form in recognizing some form under which it has just existed. Hence could the unmodified substance of Mind be presented in consciousness, it would still be unknowable; since, until there had arisen something different from it, the elements of a cognition would not exist; and as this something different would necessarily be some state of Mind, we should have the substance of Mind known in a state of Mind, which is a con- MS THE INDUCTIONS OF PSYCHOLOGY.
i tradiction. In brief, a thing cannot at the same instant be I both subject and object of thought; and yet the substance; of Mind must be this before it can be known.
Again, to know anything is to distinguish it as such or such — to class it as of this or that order. An object is said to be but little known, when it is alien to objects of which we have had experience; and it is said to be well known, when there is great community of attributes between it and objects of which we have had experience. Hence, by implication, an object is completely known when this recognized community is complete; and completely unknown when there is no recognized community at all. Manifestly, then, the smallest conceivable degree of knowledge implies at least two things between which some community is recognized. But if so, how can we know the substance of Mind? To know the substance of Mind is to be conscious of some community between it and some other substance. If, with the Idealist, we say that there exists no other substance; then, necessarily, as there is nothing with which the substance of Mind can be even compared, much less assimilated, it remains unknown. While, if we hold with the Realist that Being is fundamentally divisible into that which is present to us as Mind, and that which, lying outside of it, is not Mind; then, as the proposition itself asserts a difference and not a likeness, it is equally clear that Mind remains unclassable and therefore unknowable.
§ 60. From this absolute ignorance of the substance of Mind, considered as the something of which all particular states of Mind are modifications, let us now turn to that partial knowledge of these particular states, as qualitatively ""characterized, which lies within our possible grasp. Although 'the individual sensations and emotions, real or ideal, of which consciousness is built up, appear to be severally simple, homogeneous, unanalyzable, or of inscrutable natures, yet they are not so. There is at least one kind of feelino- THE SUBSTANCE OP Ml^TD. 149 which, as ordinarily experienced, seems elementary, that is demonstrable not elementary. And after resolving it into its proximate components, we can scarcely help suspecting that other apparently-elementary feelings are also compound, and may have proximate components like those which we can in this one instance identity.