even for tlie reception of impressions in their higher forms. Perfect vision implies a focal adjustment of the eyes, an adjustment of their axes to the requisite convergence^ a turning of them both towards the object, sometimes a turn- ing of the head in the same direction, and sometimes also a turning of the body: all which preparatory acts ai*e per- formed by muscles. Neither taste nor smell can be acute unless the muscles of the tongue and the chest do their parts in moving about the food or drawing in the air. Hearing, too, is imperfect unless the membrana tympani is strained by its muscles so that it vibrates in concord with each successive sound. Above all, the perceptions reached through touch show this dependence on the motor appa- ratus. A sensitive skin is but a small part of the require- ment, as any one may prove by closing his eyes and apply- ing his bare arm or leg to an unknown object. Tactual sensations are combined into ideas of extension, form, soli- dity, only when this sensitive skin is distributed over sur< faces capable of deriving simultaneous or rapidly-succeed- ing sensations from different parts of. the things touched; and these sensations must be joined with those muscular sensations accompanying the simultaneous and successive adjustments of the sensitive surfaces. There must be limbs to effect 'the larger and simpler adjustments, with append- ages at the ends of them to effect the smaller and more elaborate ones. And only in proportion as these motor agencies become complex, can there be complexity in the tactual perceptions. But these motor agencies — these limbs and appendages with all the muscles they are moved by, are also the locomotive and manipulating organs; and the same completeness of structure which fits them to receive com- pound impressions, fits them to perform compound opera- tions. The evolution of the sensitive or directive apparatus, is thus inseparable from the evolution of the muscular or executive apparatus.
358 GENEBAI SYNTHESIS.
§ 163. Tliis all-essential relationship must detain us somewhat longer. It will be instructive to glance at the inter-dependence of the recipio-motor functions and the dingo-motor functions (§ 18) as exhibited in the concrete. I refer to the sundry striking instances which the animal kingdom presents of unusual sagacity co-existing with unusual development of organs which, by the help of com- plex muscular arrangements,, give complex tactual im- pressions.
Why touch, the simplest and earliest sense, should, in its higher forms, be more than any other sense associated with the advance of intelligence, will perhaps seem difficult to understand. The explanation lies in the fact that tactual impressions are those into which all other impressions have to be translated, before their meanings can be known. If we contemplate the general relation between the organism and surrounding objects, we see that before they can affect it, or it can affect them, in any important way, there must be actual contact. Eating, breathing, locomotion, the destruction of prey, the escape from enemies, the formation of nests and burrows, the bringing up of young, all imply mechanical actions and reactions between the animal and its environment. The space-penetrating faculties serve but as guides to these mechanical actions; and the impressions they receive are primarily used but as symbols of tangible properties and the relations among them. Hence, only as fast as the impressions gained through the skin, and muscles become varied and complex, can there be a com- plete translation of the varied and complex impressions gained through the eyes, ears, and nose. The mother tongue must be as copious as the foreign; otherwise it cannot render all the foreign meanings. And thus, as seen in the facts referred to, a highly-elaborated tactual appa- ratus comes to be the uniform accompaniment of superior intelligence. But let us look at these facts.
Each great division of the animal kingdom supplies them.
THE CORRESPONDENCE AS INCREASING IN COMPLEXITY. 359 The Cephalopoda, which in sagacity go far "beyond all other Mollusca, are structurally distinguished from them in having several arms by which they can grasp an object on all sides, at the same time that they apply it to the mouth. Again, the crabs, which similarly stand at the head of the sub-kingdom Articulata, bring their claws and foot-jaws simultaneously to bear on the things they are manipulating. Merely glancing at these instances furnished by the invertebrate classes, let us devote our attention to those which the vertebrate classes furnish.
It will be admitted that, of all birds, parrots have the greatest amount of intellect. Well, if we examine in what they differ most from their kindred, we find it to be in development of the tactual organs. Few birds are able to grasp and lift up an object with the one foot while standing on the other. The parrot, however, does this with ease. In most birds the upper mandible is scarcely at all move- able. In the parrot it is moveable to a marked extent. Generally, birds have the tongue undeveloped and tied down close on the lower mandible. But parrots have it large, free, and in constant employment. Above all, that which the parrot grasps it can raise to its beak; and so can bring both mandibles and tongue to bear upon what its hand (for it is practically a hand) already touches on several sides. Obviously no other bird approaches to it in the complexity of the tactual actions it performs and the tactual impressions it receives.
Among mammals it is unquestionable that as a general rule the Unguiculata>3 or those which have limbs terminating in separate digits, are more intelligent than the Ungulata, or hoofed animals. The feline and canine tribes stand psychologically higher than cattle, horses, sheep, and deer. Now, that feet furnished with several sensitive toes can. receive more complicated impressions than feet ending in one or two masses of horn, is manifest. While, by a hoof, only one side of a solid body can be touched at once, the 360 GENERAL SYNTHESIS.
divided toes of, for example, a dog, can simultaneously touch the adjacent sides of a small body, if not the opposite sides. And when we remember how those toed quadrupeds of higher types, which cannot grasp with their feet, can never- theless use them for holding down what they are tearing or gnawing, we see that they can recognize tangible relations of some complexity. Moreover, when we meet with any marks of sagacity among hoofed animals, as in the horse, we find that the lack of sensitive extremities is partly com- pensated for by highly sensitive and mobile lips, which have considerable powers of prehension. Here we are naturally reminded of the most remarkable, and perhaps the most conclusive, instance of this connexion between deve- lopment of intelligence and development of the tactual organs — that seen in the elephant. I say most conclusive, because the elephant is markedly distinguished from allied tribes of mammals, alike by its proboscis and by its great sagacity. The association between the operative and regu- lative faculties stands out the more conspicuously, from the endowment of both being exceptional. On the intellect of the elephant there is no need to dwell: all know its supe- riority. The powers of its trunk, however, must be enume- rated. Note first, its universality of movement in respect of direction. Unlike limbs, the motions of which are ia most mammals more or less confined to the vertical plane, its flexibility gives it as. wide a range of positions as the human arm can take — wider, indeed, than can be taken by a single arm; and thus the elephant can ascertain the relations in space, both of its own members and of sur- rounding things, more completely than all other creatures save the Primates. Again, the trunk can grasp bodies of every size, from a pea to a tree stump; and by this means can perceive a far greater variety of tangible forms than any of the lower mammalia. The finger-like projec- tion with which the trunk terminates, is affected by minor variations of surface; and so, textures and the details of THE COREESPONDENCE AS INCREASING IN COMPLEXITY. 361 sliape can be made out, as well as general extension. Its ability to lay hold of and to lift bodies of many sizes and natures,, opens the way to a knowledge of weight as con- nected with visible and tangible attributes. The same power of prehension, used as it habitually is for the breaking-off of branches, bring-s experiences of the tenacity and elasticity of matter; and when employed, as these branches often are, for driving away flies, the swinging of them about must yield impressions even of momentum — impressions which the ability to throw small bodies (as gravel over the back) must tend to strengthen. Further, the trunk's tubular structure fits it for many hydraulic experiments, that disclose sundry mechanical properties of water unknown to other quadrupeds; and this same peculiarity, rendering it possible to send out strong blasts of air which produce motion in the light bodies adjacent, so brings yet another class of experiences. Thus, the great diversity of tactual and manipulatory powers possessed by the elephant's proboscis, is not less remark- able than is the creature's high sagacity — a sagacity which, dwelling in so ungainly a body, would otherwise be inex- plicable. Passing to the Primates, we find re- peated, under other forms, this same relation between evolution of intellect and evolution of tactual appendages. Not more in the contrasts between them and inferior mammals is this seen, than in the contrasts between the genera of the Primates themselves. The prehensile and manipulatory powers of the lower kinds are as inferior as are their mental powers. On ascending to the very intelligent anthropoid apes, we find the hands so modified as to admit of more complete opposition of the thumb and fingers; the bones of the forearms so articulated as to give the hands greater powers of rotation; the arms attached to the body in such a manner as allows them increased range of lateral movement. In all the more developed of the order^ the fore-limbs are so. constructed that an object can be grasped in one hand while it is being manipulated by the other, or by the lips and teeth — can be held at the most convenient distance from the eyes — can be applied to any part of the body, or any neighbouring object. So that far more complex perceptions of size,, shape, structure, texture, hardness, weight, flexibility, tenacity, &c., and of their various combinations, can be reached by them than are accessible to creatures whose limbs are less elaborately constructed.
How, in man, recipio-motor and dirigo-motor structures and functions are both still further elaborated, scarcely needs saying. As contemplated from an obverse point of view, the connexion between them is abundantly exempli- fied in works on natural theology. All that we need here notice is the extent to which, in the human race, a perfect tactual apparatus subserves the highest processes of the intellect. I do not mean merely that the tangible attributes of things have been rendered completely cognizable by the complex and versatile adjustments of the human hands, and that the accompanying manipulative powers have made pos- sible those populous societies in which alone a wide intelli- gence can be evolved. I mean that the most far-reaching cognitions, and inferences the most remote from perception, have their roots in the definitely -combined impressions which the human hands can receive.
This inter-dependence of the impressibilities and activities as displayed in the course of human progress, is so striking and instructive as to demand special attention, even at the cost of a farther suspension of the general argument.
§ 164. All developed science, consisting as it does of quantitative prevision — dealing as it does with measured results, is lineally descended from that simplest kind of measurement achieved by placing side by side the bodies held in the hands. Our knowledge of the forces governing the Solar System is expressed in terms that are reducible, THE CORRESPONDENCE AS INCREASING IN COMPLEXITY. 363 by an ultimate analysis, to equal units of linear extension, which were originally fixed by the direct apposition of like natural objects.* And the undeveloped sciences that have not yet passed the stage of qualitative prevision, depending for their advance, as they do, either on experiments re- quiring skilful manipulation or on observations implying dissection and other analogous procedures, could not have reached this stage in the absence of a highly-developed manual dexterity.
But this intimate connexion between the directive and executive faculties, is even still more clearly to be traced in certain other phenomena of civilization. This mutual dependence of the regulative and operative powers, which Anaxagoras had a glimpse of when he uttered his hyper- bolical saying that animals would have been men had they had hands, is remarkably and conclusively exemplified in the reciprocity of aid between the Sciences and the Arts. It needs but a little analysis to show that "under their psychological aspects, Sciences and Arts represent what in their lowest forms we call sensory and motor processes. The perceptions gained through sensory organs and the actions performed by motor ones, respectively rise, by com- bination, into scientific generalizations and manufacturing operations. A comparison of the extremes does not very obviously show this; but on looking at the transitions the filiation becomes manifest. It cannot be denied that the complex perceptions of which each sense is the agent, together with the still more complex perceptions reached by co-operation of several senses, are forms of the organism's impressibility; nor that the combinations, more and more involved, of motive, locomotive, and manipulative powers, are forms of the organism* s activity. It cannot be denied that out of these complex perceptions, woven into general ideas still more complicated, finally arise the previsions of * For explanation, see essay on " The Genesis of Science."
364 GENERAL SYNTHESIS.
science; nor that all handicrafts, and after them the higher processes of production, have grown oat of that manual dexterity in which the elaboration of the motor faculty ter- initiates. If, looking at the entire range of phenomena, we seek out the essential nature of the changes an organism goes through in adjusting " itself to the environment — if we divide these changes, as we must, into those which external objects impress on it, and those by which it appropriately modifies its relations to the external objects — if we name these respectively, the directive changes and the executive changes; we see clearly that sensations, perceptions, con- ceptions, generalizations, and all forms of cognition, come under the one, while contractions, locomotions, and all kinds of operations, come under the other; and that Science and Art, so far as they are separable at all, belong, the one to the first division and the other to the last.
This truth being recognized, we shall perceive the signi- ficance of the reciprocity of services between the Sciences and the Arts. Each great step towards a knowledge of laws has facilitated men's operations on things; while each more successful operation on things has, by its results, facilitated the discovery of further laws. Astro- nomy and agriculture, geometry and the laying out of buildings, mechanics and the weighing of commodities — these were among the earliest relations of the two. Pre- sently geometry, as developed by artificers, acted on astro- nomy; and astronomy reacted to the great advancement of geometry. Through the medium of the scales, mechanics, joined with the science of number, influenced the xnotal- lurgic arts, gave definite alloys, introduced metallic instru- ments, and by so doing advanced the accuracy of astro- nomical and other observations, and improved all those j pfocesses of production for which metallic tools are employed. Metallurgy, too, by supplying plane and concave mirrors, initiated optics; and the first proposition in har- monics was reached by the help of strings and weights which the arts furnished. As we advance to modern times the connexion becomes increasingly conspicuous. We see id in the dependence of navigation on astronomy, mag- netism, and meteorology; and the aid rendered to mag- netic and meteorologic science by navigation — in the \ development of geology by mining, quarrying*, and wellsinking; and the guidance which, geology now gives to the ; search for coal, metals, and water. The compounds and elements with which chemistry deals were at first brought to light by the arts; and the arts are now all more or less dependent on chemistry. There is scarcely an observation now made in science, but what involves the use of in- struments supplied by the arts; while there is scarcely an art-process but what involves some of the previsions of science. This fact, that the mutual aid becomes ever more active, further elucidates the general truth we are contemplating. For as, when tracing upwards the direc- tive and executive faculties, we found that their dependence on each other grows continually greater — that complete visual and tactual perceptions are impossible without com- plex muscular adjustments, while elaborate actions require the constant overseeing of the senses; so, among these still higher cognitive and operative processes, we now find a reciprocity such that each further cognition implies elabo- rate operative aid, and each new operation implies sundry elaborate cognitions.
These correlations are equally well, or even still better, seen in the objective appliances used. We may properly k say that in its higher forms, the correspondence between the organism and its environment is effected by means of supplementary senses and supplementary limbs. All ob- serving instruments, all weights, measures, scales, micro- meters, verniers, microscopes, thermometers, &c., £re artificial extensions of the senses; and all levers, screws, hammers, wedges, wheels, lathes, &c., are artificial exten- sions of the limbs. The magnifying glass adds but another 366 GENEJSAL SYNTHESIS.
lense to the lenses existing in the eye. The crowbar is but one more lever attached to the series of levers forming the arm and hand. And the relationship which is so obvious in these first steps, holds throughout. This being perceived, a meaning becomes manifest in the fact that the development of these supplementary senses is dependent on the develop- ment of these supplementary limbs, and vice versa. Accu- rate measuring instruments imply accurate instruments for turning and planing \ and these cannot be made without the aid of previous measuring instruments of some accu- racy. A first-rate astronomical quadrant can be produced only by a first-rate dividing engine; a first-rate dividing engine can be produced only by first-rate lathes and cutting tools; and so, tracing the requirements backwards, it be- comes obvious that only by repeated actions and reactions on each other, can directive and executive implements be brought to perfection. Only by means of artificial limbs can artificial senses be developed; and only through arti- ficial senses does it become possible to improve artificial limbs.
Lastly, it may be remarked that not only do the direc- tive and executive elements of the correspondence develop hand in hand, but the complications they reach have analo- gous characters. That union of generalities with special- ities which we found to distinguish the highly-involved cog- nitions of Science, is visible also in the highly-involved operations of Art. Just as a particular conclusion in Science is reached by putting special data to a general prin- ciple, which general principle concreted by other data gives other conclusions; so, a particular art-product is obtained by subjecting to special manipulations the material obtained by some more general process, which material subjected to other manipulations, yields other art-products.
§ 165. And now on returning from this long and elabo- rate digression, bringing with us the conceptions arrived at, THE CORRESPONDENCE AS INCREASING- IN COMPLEXITY. 357 wo find tliat they serve greatly to elucidate tie subject of the chapter — the increase of the correspondence in com- plexity.
While tracing the inter-dependence of impressibilities and activities as they evolve into regulative and operative faculties of high orders, the growing complexity of the correspondence has been illustrated in several ways. The progressing heterogeneity of the impressions received through each sense has shown it; and still more the pro- gressing heterogeneity of the combinations of impressions yielded by co-operation of the senses. The compounding and re-compounding of the muscular movements, alike of each limb by itself and of the limbs and body together, have further exemplified it. Above all it has been shown in the advance of this reciprocity between the recipio-motor acts and the dirigo-motor acts, which, becoming ever closer, becomes ever more involved; so that eventually a single accurate perception implies complex muscular ad- justments, and a single exact operation implies the guidance of complex perceptions. In all which it is manifest that, as alleged at the outset, advance in speciality of correspon- dence is in its higher forms achieved through advance in complexity of correspondence.
How this increase of the correspondence in complexity which we have followed up through the higher animals to Man, has been continuing during civilization, has just been shown: the advance of the Sciences and the Arts abundantly exemplified it. One note-worthy fact, however, remains to be named. Human evolution, considered under this aspect, is not adequately represented objectively by the developing Sciences and the Arts. It must be looked at also on its sub- jective side as developing faculty. While there has been advance in the complexity of the cognitions and opfera- tions that have been age by age attained to, there has been advance in the ability to receive complex cognitions and perform complex operations.
GENERAL SYNTHESIS.
Por scientific and artistic progress is due noo simply to "the accumulation of knowledge and of appliances: the im- pressibilities and the activities have themselves grown to liigher complications. There is evidence from various quarters that the minds of the inferior human races cannot respond to relations of even moderate complexity; much less to those highly-complex relations with which advanced science deals. According to the traveller Lieutenant "Walpole, it is remarked of the Sandwich islanders, by their teachers,, " that in all the early parts of their education, they are exceedingly quick, but not in the higher branches, that they have excellent memories, and learn by rote with wonderful rapidity, but will not exercise their thinking faculties/1 That is to say, they can readily receive simple ideas but not complex ones. Again, of the Australians we read that " some of them are very quick at acquiring know- ledge, but they have no power of combination or concentra- tion/** The reports of Hindoo schools disclose, though in a less marked manner, the same fact. One of the reasons assigned in the United States for not educating negro children along with white children, has been that after a certain age they " do not correspondingly advance in learning— their intellects being apparently incapable of being cultured beyond a particular point/"7 And this statement, which, might else be suspected, of bias, agrees with that made respecting the same race in Africa by Sir Samuel Baker* who says; — " In childhood I believe the negro to be in advance, in intellectual quickness, of the "white child of a similar age, but the mind does not expand— it promises fruit but does not ripen/* f So, too> of the Andaman chil- dren we read that they ff eafcb. up words readily and repeat tiiem, but seem incapable of connecting words with corre- sponding ideas." J Evan tile finest uncivilized races show * See Proceedings of the Ethnological Society.
t The Albert EPyanza. VoL I, p. 289.
i Trans. Etk Soc. Hew Series, "Vol. IV, p. 210,.
TUB CORRESPONDENCE AS INCREASING- IN COMPLEXITY. 369 us the like limitation. " Without genius for discovery, and incapable of generalizing/* the New Zealanders " are never- theless apt at acquiring the rudiments of learning " # # * "boys at ten years of age are more intelligent than English boys; but, as a rule,, few New Zealanders could be taught to equal Englishmen in their highest faculties."* In all these cases, as also in the minor cases continually occurring among ourselves of inability to understand reasonings passing a cer- tain degree of abstruseness, vthe interpretation is that the intellect has not reached a complexity equal to the com- plexity of the relations to be perceived. Not only with purely intellectual cognitions does this hold; it holds also with what we distinguish as moral cognitions. In the Australian language there are no words answering to justice, sin, guilt. Among most of the lower races, acts of generosity or mercy are incomprehensible. That is to say, the more involved relations of human actions in their social bearings are not cognizable. We must therefore conclude that the complex manifestations, intellectual and moral, which distinguish the large-brained European from the small-brained savage, have been step by step made pos- sible by successive complications of faculty.