differentiation is by no "means complete. Many of the actions! are partly voluntary, partly automatic; and may be performed j with various degrees of consciousness, or without conscious- J ness. This is implied by the fact that sensations can be re- ceived, an^(^qmppui^moY§ments performed, inJ/Ee.,.absence °^ Mi£jgreat ^^Q113 cefi^res • -^SESEiSSi® on frog§ yield clear proof that actions of cpnsiderable * Carpenter's Principles of Comparative Physiology, p. 665.
398 SPECIAL SYNTHESIS.
may be efficiently executed without the aid of the brain (§ 22). The vivisections of Longet, Vulpian, and others, show that mammals continue to feel and retain certain of their locomo- tive powers, when both cerebrum and cerebellum have been r£moj;ed; and'l;hari)7rQls similarly deprived of these great cephalic ganglia can still walk about, fly, and even pick up food. Nay, there are cases on record of infantp that have for days continued to breathe, cry, suck, and go through various movements, although born without either cerebrum or cere- „ bellumv *"* Apart from evidence of this kind, the per- I sonal experiences of every adult demonstrate to him that I there are many actions belonging to the psychical division, I which either may or may not enter into the mental current. The motion of the legs is necessarily accompanied by various muscular and tactual changes. These, together with the state we call volition, may be distinctly present to con- sciousness— may be thought of as by a child learning to walk; or they may, as in ^ordinary walking, be left almost wholly out of consciousness. The processes we perform whjle^jeatmg display a similar relation. The several acts by which each morsel is selected, cut, prepared, and carried to the mouth, may perhaps be held to enter into the current ^ of our thoughts; though in general, and especially during ^conversation, they obtrude themselves on consciousness very slightly. But many of the^ impressions and mpjbions involved, are next,to uncon^ouZ The^tactual feelings which the knife-handle gives, the contractions by which it is grasped, and the muscular changes which the arms are every moment undergoing, scarcely at all occupy the atten- tion, ^^ftj^at 9Sij^^ or quasi- psychical actions going on in the organism.
thread of consciousness; while t£er6ihers form one or more~3Is5n as it were, occasionally inosculate with the thread of consciousness.* * I find that there may sometimes he detected as many as five simulta- neous series of nervous changes, which in various degrees rise into conscious- THE NATURE OF INTELLIGENCE. 399 So thafc only by gradual differentiation have the actions constituting psychical life become specially successive, in- stead of simultaneous and successive; and the distinction is not even now complete. In the lowest types each part of the organism, while it performs by and for itself all other vital functions, also responds by and for itself to external stimuli; and the psychical changes,, or what foreshadow them, are both simultaneous and successive to as great an extent as the physical changes. When a nervous system makes its appearance, these incipiently-psychical changes become slightly co-ordinated — have their various strands connected. As the nervous system develops and integrates, the twisting of these various strands of changes into one thread of changes grows more decided. J3ut to the last their union remains imperfect. The vital actions consti- tuting the subject-matter of Psychology, while distinguished from other vital actions by their tendency to assume the form of a single series, never absolutely attain that form.
§ 178. This distinction between the psychical and thej physical life will be most clearlj understood, if weTconsiderj flEFmo^in which it first appears and __ tt^Jeaddng stages of I its progress.
Throughout the homogeneous tissue of which the lowest creatnres consist, there is complete community of actions. The vital processes go on simultaneously in many place? alike. These primordial organisms, if organisms they can 8S called, exhibit no differentiations of structure or func-j ad thus th^J;w^j^^ ivisions of each, are. in th^ybejrinning. one. I • that we cannot call any of them absolutely unconscious. When walking! there is $& locomotive series; there may be, under certain cir- cumstances, a tactual series; there is very often (in myself at least) fn auditory series, constituting some melody or fragment of a melody which1 haBB&i me; and there is the visual series: all of which, subordinate to the dominant consciousness formed by some train of reflection, af e continually ) crossing it and weaving themselves into it.
> SPECIAL SYNTHESIS.
The first great differentiation established is that between the inner and outer tissues— the substance of the body and its limiting membrane. The parts of the original protoplasm are subject to but a single contrast of conditions — that between contact with one another, and contact with the environment. The external portions are bathed by the surrounding medium; the internal portions are not. And in response to this primary unlikeness of conditions, there eventually arise unlikenesses of structure and function.
That which is permanently outermost takes on the modified form of vital action which its circumstances demand. That which is permanently innermost similarly assumes a more specialized order of activity (Prin. of Bio., § 287).
? The division of labour thus commenced may be considered as at first physiological only. In virtue of its 1 position, the surface necessarily monopolizes the duties of absorption — the taking in of water and nutriment and oxygen; while to the included mass remain such duties as its inclusion permits. And when, by involution of the I surface, a stomach is formed, the change implies a furthei i separation of duties, such that nutrition is chiefly confined • to one part of the limiting membrane and aeration to another. But the advance is not an...adran.ce in the physiological division of labour solely. It is at the same time anjadyance,.towards Jhe segaraSoii^of j>sy chical actions from.
phy sical_pnes; and is even a first s^pTJowards'' bringing psychical actions into serial order. Necessarily assuming the vital offices entailed by its externality, the skin also assumes the office of receiving all those impressions prtjch form the raw material of intelligence. The mechanical and other changes going on in the environment, can be responded to by the organism only when it is affected by tffemj and any change they work in it must be proximately experienced by its surface. The Ja^ then, being I the part immediately subject to the various HSds of exter- Jnal stimuli, necessarily becomes the part in which psychical...-...------------...- - —:"..."...^..^ftswjs^— *•*" THE ttATUBE OF INTELLIGENCE. 403 changes are originated. As contrasted with the contained! substance, it comes to be more especially concerned in that adjustment of inner to outer relations which constitutes intelligence. But now mark the implication. The changes constituting the physical life continue to go on simultaneously throughout the entire mass. Those which foreshadow the psychical life are, in an increasing degree, localized on the outside of the mass — belong to its; outside primarily and affect some other parts secondarily. Speaking generally, therefore, we may say that while the! physical changes are being everywhere initiated throughout a solid, the psychical ones, or rather those out of which | psychical ones arise, admit of being initiated only on a j surface. Hence, even by this primary differentiation the incipient psychical life comes to be distinguished from the purely physical life, by the diminished quantity of simul- taneous changes it includes.
Subsequent differentiations have like natures and results.1 This sensitiveness which forms the basis of psychical lifej is"*"in ine beginning diffused uniformly over the whole surface; but it presently becomes in some degree concen- tratecl. Though, generally, all parts of the skin remain impressible by touch, yet certain parts, having positions which expose them to frequent tactual impressions, become more susceptible than the rest; and in these parts most of the sensations arise. That is to say, the ej)i-peripheral ch^^s^qnning^ the raw matejial,QLfetelligence, by being restricted in the area of their occurrence, have the charac- teristic of simultaneity further limited; and the more highly developed the tactual apparatus the more marked is the limitation.
Still greater is this limitation rendered by the eyolutipn of special senses. The olfactory and gustatorj sensatiorS are localized in smaller tracts than is the sensation of touch; and each of tnese tracts is little, if at all, capable of undergoing more than one change at a time. Yisujland D IT" 402 SPECIAL SYNTHESIS.
auditory impressions are receivable only witHn yet narrower areas; and even the two areas susceptible of each become functionally one. The ears are simultaneously affected by the same sounds; and in the highest creatures the eyes, being so placed as to converge their axes on the samo object, yield to consciousness what seems to be one image. Nay, erac within each group of visual feelings concentration is manifest. The greatest sensitiveness of the retina is confined to a minute spot; and the feelings initiated in this spot domi- nate over the others in consciousness. If we add that when the most advanced intelligence is reached, the sensations arising in the nose and the palate are but occasional, while , those arising iu the eyes and ears are perpetual -, it will be seen to what extremely small portions of the organism the ; changes which form the chief raw materials of intelligence are ultimately confined.
Continued differentiation^ajQcl^integration, thus concen- • • trating* the actions out of which psychical life is evolved, first on the surface of the organism, afterwards on certain regions of that surface, afterwards on those most specialized! parts of it constituting the organs of the higher senses, and finally in minute parts of these parts, necessarily render the psychical Jife more and mot%e distinct from the physical life by * bringing its changes more and more into serial order. We have nothing to do with the progressive development of the nervous system, and the actions that are carried on throughout its mass. These internal actions are initiated by the external ones to which the senses are subject. And just in proportion as the external ones tend towards the serial form, the consequent internal ones do the same.
p § 179. This growing seriality in the psychical changes isi, "indeed, necessf&ated by advance of the correspondence. In I other words* the advance of the correspondence, the de- .hrelopment of consciousness, and the increasing /tendency THE NATURE OP INTELLIGENCE. 403 towards a linear order in the psychical changes, are different aspects of the same progression.
For how only can the constituent changes of any complex correspondence be co-ordinated? Those. abilities which an intelligent creature^ possesses, of recognising diverse ex- ternal objects and of adjusting its actions to composite phe- nomena, of various kinds^, imply a power of combining many separate impressions. These separate impressions are re- ceived By the senses — by different parts of the body. If they go no further than the places at which they are received, they are useless. Or if only some of them are brought into relation with one another, they are useless. That an effectual- f adjustment may be made/ they must be all brought into rela- 1 tion with one another. But this implies some centre of com- f munication^commpn to them. all, through which they severally gass; and as they cannot pass through it simultaneously, they must pass through it in succession. So that as the external phenomena responded to become greater in number and more complicated in kind, the variety and rapidity of the changes to which this common centre of communication is subject must increase — there must result an unbroken series of these nervous changes, the subjective face of which is what we call a^ Of course I dc^gfe m^mtl^^^^^^laactipn1s thusjbe cornel, m^ftial actions, AS was said in §„§ 41 — 51, 62, 63, " no^effg^ en&jbles us to. assimilate ^MindLan^ Motion. I am merelj showing a p(]^csJleUsjai between a certain physical^evolutiox and the cofreEEive psychicaTevqi^tion.
§ 180." That mental phenomena constitute a series is a doctrine of old standing, and one the general truth of which none call in question. As we have seen, however, it is to be understood in a qualified sense. When the facts are c<Jh- templated objectively, it becomes manifest that though the changes constituting intelligence. approach to a single suc- cession, they do not absolutely form one — that there are SPECIAL SYNTHESIS.
constantly being performed actions of an intelligent kind which are not present to consciousness— and that, through the many gradations between completely-conscious actions and completely-unconscious ones, the psychical changes merge into those which we distinguish as physical. When we Consider the facts subjectively— when we interrogate consciousness/ we find that though the general seriality of the changes is obvious, there are many experiences which make us hesitate to assert complete seriality. Let us ex- amine one.
The visual impressions we receive from moment to moment, though ordinarily regarded as single states, are in reality multiple ones; and it becomes a perplexing question how far each of these can be considered a member of a linear series of changes. Besides the particular thing to which the eyes are directed, many other things are partially seen; and no clear separation can be made among the degrees of definiteness with which they are presented to conscious- ness. Only one point of the object looked at is perceived with perfect distinctness. Yet it cannot be said that consciousness is entirely occupied with this one point; for the object as a whole may be identified by the single glance directed to this one point. Obviously our consciousness of things within the visible area, becomes smaller as they become more remote from the centre to which the axes of the eyes converge. Obviously there is nx> particular distance from this centre at which we can say that consciousness ceases. And thus there would seem to be a great number of nascent consciousnesses of different intensities existing at the same moment. Only by a certain license, then, can the internal change pro- , duced by a visual impression be called single. Strictly speaking, it is a multitude of simultaneous changes bound together. Still more conspicuous becomes the qualification with which we must accept the doctrine that psychical changes are distinguished by their seriality, when.
THE NATURE OP INTELLIGENCE. 405 from fclie state of consciousness produced "by a visual im- pression^ we go on to observe the state of consciousness known as the resulting perception. The various distances, solidities, structures, &c., which appear to be immediately given in the impression, being really known by inference, severally imply many changes; and these changes are practically synchronous with those constituting the im- pression itself, since the positions and natures of the ob- jects are recognized in the instant of perception. So that beyond that complexity of a visual consciousness due to the many co-existing feelings and relations it includes, there is a further complexity caused by the many represented feel-' ings and relations, which are so closely united with the presented ones as seemingly to form with them one con- sciousness.
Nevertheless, the doctrine that psychical life is distin- guished from physical life by consisting of successive changes only, instead of successive and simultaneous changes, may be shown from the very facts here cited. For though a visual impression makes us nascently con- scious of many things, yet there is always some one thing of which we are more conscious than of the rest. And when we so look at this one thing as to perceive it in the true sense of the word — to know it as such or such, we are almost exclusively occupied with it. Though the images of other things are all the while being impressed on the retina, and are producing changes there, yet these are not appreciated internally — are scarcely more than physi- cal changes — do not undergo that co-ordination with others which constitutes them psychical changes. And this fact, that in proportion as any object seen is distinctly thought of, the other objects withinr view cease to be thought of, shows clearly how consciousness becomes more definitely serial as it rises to a higher form. In brief, we may say that while the outer strands of changes which constitute the thread of consciousness are indefinite and loosely adhe- SPECIAL SYNTHESIS.
SPECIAL SYNTHESIS.
rent, there is always an internal closely-twisted series of changes, forming what we may consider as consciousness proper.
Psychical changes therefore, if not absolutely distin- guished from physical changes by their seriality, are rela- tively so distinguished; and in proportion as they assume that most developed form constituting rationality they co- here into a seemingly-single succession of states. Though these states are physiologically composite,, and were once psychologically composite, yet, to the extent that they have become consolidated elements of thought they may rightly be regarded as severally simple.
§ 181. Such, then, is the.outcome of our examination. Gradually differentiated from the lower order of changes constituting bodily life, this higher order of changes con- stituting mental life assumes -a decidedly-serial arrange- ment in proportion as intelligence advances. Though this serial arrangement never becomes complete, yet in the human consciousness it approaches completeness; and . the highest processes of this consciousness are possible only on condition that its successive states, compound as they may be in nature, shall comport themselves as practi- Jcally elementary. The fact that every proposition ex- ;] presses a relation, an<3 that every relation.subsists between pwo terms, of itself proves that distmct tlxchught necessi- Jtates serial arrangement of its.components.
A succession of changes being thus tike subject-matter of Psychology, it is the business,of Psychology to deter- mine the_h^^of^OT_successi<m. That they follow one another in a particular way, the existence of Intelligence itself testifies. The problem is to explain their order.
CHAPTER II.
THE LAW OF INTELLIGENCE.
§ 182. All Life; whether physical or psychical, being the combination of changes in correspondence with external co- existences and sequences, it results that if the changes constituting psychical life occur in succession, the...law^ of their successipn^must^ be the law of their correspond- ence.
An adequate statement of this law is by no means easy to find. Did the phenomena in the environment form,, like the phenomena of consciousness, a succession, there would be no difficulty. The entire fact would be expressed by saying that the internal succession, parallels the external suc<y*saion. But the environment contains many successions of pheno- mena, going on simultaneously. Further, there are found in it a great variety of phenomena which are not successive at all, but co-existent. Again, it is unlimited, and the phe- nomena it includes are not only innumerable, but insensibly pass into a relative non-existence as the distance from the organism increases. Once more, the environment, relatively considered, is ever varying as the organism moves from place to place. Howjbhen can th^ucce^^ changes bejjnjwj^waj ^foratulated^? How is it possible to express the law of a single series of internal phenomenal terms of its correspondence with an infinity of external phenomena, both serial and non-serial, mixed in the most 408 SPECIAL SYNTHESIS.
heterogeneous manner, and presented to the moving or- ganism in fortuitous combinations never twice alike?
Were it not that the inner relations must correspond with, the outer ones; and that therefore the order of states of consciousness must be in some way expressible in terms of the external order; we might despair of finding any general law of psychical changes. Even as it is, we may be certain that no general law can apply to extended portions of the series of changes. Mainly dependent as these must be, on the assemblages of things by which the organism is en- vironed, and on the new assemblages perpetually disclosed by its movements, they can be no more formulated than these assemblages can be formulated. Evidently, it is in the immediately-connected changes, and small groups of changes, rather than in the longer concatenations of changes, that a law is to be sought.
§ 183. A correspondence between the internal order and the external order, implies that the relation between any two states of consciousness corresponds with the relation between the two things producing them. How corresponds? The two states of consciousness occur in succession; and all successions are alike in so far as they are simply succes- ^ sions. In what, then, can the correspondence consist? In this, that the persistence of the connexion between the states of consciousness is proportionate to the persistence of the connexion between the agencies to which they answer. The relations between external objects, attributes, acts, are of all grades, from the necessary to the fortuitous. The relations between the answering states of consciousness must similarly be of all grades, from the necessary to the for- tuitous. When any state a occurs, the tendency of some other state d to follow it, must be strong or weak according to the degree of persistence with which A and D (the objects or attributes that produce a 'and d) occur together in the1 eiirironmeiit. If, in the environment, there is a more per- THE LAW OF INTELLIGENCE. 409 sistent occurrence of A with B than of A with D; then, tlie maintenance of the correspondence implies that when a arises in consciousness, & shall follow rather than d. These are manifest requisites. If the strengths of the connexion "between the internal states are not proportionate to the persistences of the relations between the answering external H agents, there will be a failure of the correspondence — the I inner order will disagree with the outer order.
I A due understanding of the matter may best be obtained f by examining the several objections to this general statement.
I § 184. The acts of animals exhibit countless failures of ] I the internal order to parallel the external order. In the i moth, which, flies at a candle-flame, there exists no relation I of psychical states answering to the relation between liglit jf and heat in the environment. The connexion between the ^ odour of a flower and the contained honey, is duly responded I • to by sequent actions in the moth; as is also the connexion i between a certain change in the field of view and the; approach of a living body. But there is no internal adjust- £ inent by which, after the visual impression produced by a flame, anything like the feeling of a burn is suggested; and ;. I hence the creature's death. Again, the birds which on uninhabited islands allow explorers to approach close to them, manifestly lack that co-ordination of psychical changes by which the birds of our woods and moors are led to fly the sportsman. Externally there co-exists with particular appearances, a destructive activity; but internally, the state of consciousness roused by these appearances is not followed by any state of consciousness representing a destructive activity: and a risk of being killed is the consequence. A child's percepjbion of some brightly-coloured berry does not excite an idea of pain, or of the word " poison/* but more probably some idea of a pleasant taste; and should injurious chemical properties co- exist with these attractive visible ones, the child's life may be endangered. But in all cases" 410 SPECIAL SYNTHESIS.
of this kind what is the implication? Do we not speak of the injuries suffered as resulting from lack of sagacity? or .as evincing ignorance? And is it not a corollary that,, as non-conformity of the inner to the outer order is want of intelligence, conformity of the inner to the outer order is that in which intelligence consists?
A few instances in which the failure of the correspondence is not total but partial, will enforce th'is conclusion. The dog that comes on hearing his name called,, usually does so expecting to find his master or some member of the family; but if, as occasionally happens, his name is called by a stranger, the sequence in his states of consciousness is not adapted to the external facts: he makes a mistake. Among the Australian savages, who mostly meet with violent deaths, it. is the belief that any one who dies without apparent cause has been killed by an unseen foe; and a stranger who hap- pens to be found near at hand is liable to be sacrificed as the supposed assassin. Here, though the mental connexion between death and enmity very generally agrees with the connexion in the environment, it by no means uniformly does so. The earlier chemists, by a large number of experiences respecting the combinations of acids and bases, were led to think of substances that neutralized bases as substances having sour tastes; but this relation of ideas, though very generally in harmony with external relations, is not always so.
What, now, do we say of cases like these, in which the inner order does not completely answer to the outer order? We say that they imply a low degree of intellect, or a limited experience, or a but partial enlightenment. And the disappearance of these discrepancies between thoughts and facts we speak of as an advance in intelligence.
$ 185. " But how does this conception include co-exist- ences? " it may be asked. " In so far as the environment presents motions and changes, there is no difficulty in understanding the law of intelligence to be, that the THE LAW OF INTELLIGENCE. 4H strength of the tendency which the antecedent of any psychical change has to be followed by its consequent, is proportionate to the persistence of the union between the external things they symbolize. But when this union is noi} between successive things but between simultaneous things — not a union in Time but a union in Space., it is less easy to see how the parallelism between the inner and the outer order can result from fulfilment of this, law. The con- nexion between two states of consciousness occurring in succession, can very well represent the connexion between two external phenomena occurring in succession. But if it can do this, it cannot also represent the connexion between two external phenomena not oqcurring in succession."