But that advancing generality of correspondence here to be contemplated, shows itself in the recognition of con- stant co-existences and sequences other than those which characterize special classes — co-existences and sequences common to many classes that have come to be regarded as entirely unlike. Instead of being seen in a response to the constant relation between a particular scent, and the colour, size, form, actions, and cries, of the creature 344 GENERAL SYNTHESIS.
possessing it; tMs progress is seen in adjustments to such relations as those between bulk and weight, inanimateness and passivity — relations which extend beyond class limits, and obtain under great dissimilarities. Obviously the growth of generalities of this order must be opposite in direction to the growth of the preceding ones.
To trace up this growth from the lower to the higher forms of life, after the manner pursued in previous chapters, is extremely difficult if not impossible. For this species of correspondence does not manifest itself in distinct, un- combined forms. The extensions of the correspondence in Space and Time, as well as its increase in Speciality, are experimentally demonstrable; but an internal relation parallel to some external relation which is not peculiar to special classes of things, cannot be separately identified in the conduct. Giving origin to no particular acts, but serving simply to modify the acts otherwise originated, it can bo discovered only by analysis of these.
Hence our course must be to ascertain the conditions under which alone advance of the correspondence in gene- rality becomes possible; and then to show how the pro- cesses of evolution already described, give rise to these conditions. Let us do this.
§ 157. The establishment of a generality of this higher kind, embracing classes superficially dissimilar, implies a power of recognizing attributes as distinguished from the objects possessing them. Before any two properties that are found together under many varieties of size, form, colour, texture, temperature, motion, &c., can have their constant relation of co-existence responded to by the organism, the organism must be able to identify these two properties, as separate from their accidental accompaniments. The formation of special class-generalities, which group together clusters of phenomena that greatly resemble one another in all respects, requires no distinct parting of attributes. But TRS CORRESPONDENCE AS INCREASING IN GENERALITY. 345 where tlie resemblance is confined to some one essential relation common to many cases which in other respects differ, it is clear that unless the elements of this relation are separately cognizable there can be no response to it.
And now the truth to be noted is that increase of the correspondence in speciality, inevitably brings about this parting of attributes. There cannot be a multiplication of distinguishable classes, without there being a simul- taneous approach to the perception of properties as distinct from objects. For if, ascending from the lowest creatures by which but few attributes are cognizable,, we advance to those capable of being impressed by a greater and greater number of attributes, it is clear that in proportion as the groups of attributes become increasingly varied and special, there must be more frequent dissociations of particular at- tributes from the rest. Forms, colours, sizes, sounds, scents, motions, are found in all combinations. These two kinds of animals are alike in everything but colour; those two agree in colour but differ in form and scent; and the others have little in common but size. The property A occurs here along with the properties B, C, D; there along with C, F, H; there along with E, G, B; and so on with each property to a greater or less extent. Hence it must happen that by multiplication of experiences, the impres- sions produced by these properties on the organism will be disconnected, and rendered so far independent in the organism as the properties are in the environment. Whence must eventually result a power to recognize attributes in themselves, apart from particular bodies.
It may, indeed, be shown that progress of the corre- spondence in speciality, itself becomes possible only in pro- portion to the progress of this analysis. An analogy will best show the dependence. Let a chemist be required to produce artificially sundry compound bodies; what is implied in the execution of his task? The implication is that he knows the composition of each of these bodies.
346 GENERAL SYNTHESIS.
But what does knowledge of their composition pre-suppose? It pre-supposes that they have been severally resolved into their constituents. And the formation of each required compound implies that its constituents are united in the right proportions. Well, the process of identifying any object is a synthesis of impressions, corresponding to certain united properties which the thing displays; and similarly implies a recognition of the separate impressions which correspond with the separate properties. The botanist who knows a particular flower not by the fructifi- cation alone, in which it is like many others — not by the number of its petals, which is a usual number — not by their forms in which they do not differ from these, nor by their colours in which they do not differ from those — not by the calyx, nor the bracts, nor the leaves, nor the stalk, sepa- rately considered, but by all these taken together; obvi- ously effects the identification by a synthesis of attributes. And that which he does in a deliberate and conscious way, is done consciously or unconsciously in every case where an object is recognized as of special nature — is done in a degree proportionate to the speciality of the correspondence. Should it be said that this statement contradicts the previous statement, since the one represents the analysis of attributes as a pre-requisite to speciality of correspondence, while the other represents the analysis of attributes as resulting from increase of the corre- spondence in speciality, the reply is that the two processes go on in mutual dependence, perpetually acting and reacting on each other. Every advance in speciality pre- sently renders the analysis of attributes more precise; and each step in the analysis of attributes makes possible a higher speciality.
Thus the course of evolution described in previous chapters, is necessarily accompanied by a disentangling of properties from one another, ending in an ability to recog- nize them in the abstract. Later and more slowly, relations* THE CORRESPONDENCE AS INCREASING IN GENERALITY. 347 both of sequence and of co -existence must coine to be discriminated one from another, and segregated into kinds nnd degrees of relations. An increasing speciality in the adjustments to mechanical changes, pre-supposes an in- creasing decomposition of such changes into their elements — a growing power to distinguish velocity of motion, direction of motion, acceleration and retardation of motion, kind of motion in respect of simplicity or complexity, and so on; and where non-mechanical sequences also come to be responded to, a parallel analysis must accompany a parallel progress in speciality.
When these analyses have been considerably extended, there arises, and only then arises, a possibility of advance in generality of correspondence. Relations between properties possessed in common by objects of widely different kinds, can be perceived as soon as these properties are separately cognizable. And a still higher progress in the specializa- tion of the correspondences, ultimately brings about this remaining step required for generalization of them. For if, as we have seen, the multiplication of special correspon- dences must be accompanied by the dissociation of variably- united attributes; then, when the variably-united attri- butes displayed by a group of different classes have been as it were disintegrated in the consciousness of the organism, the attributes that have not been disintegrated must begin to stand out from the rest, as remaining always constant amid these inconstancies. Hence there must be established in the organism a constant relation corresponding to the constant relation between these attributes; and this consti- tutes the advance in generality we are looking for. Fur- ther, as the comparatively-constant relations thus first generalized from the experience of but few classes, will, in the majority of cases, be proved by wider experience to bo not everywhere constant; and as, by the accumulation of these wider experiences, the same process must be gone through with the comparatively-constant relations as before 348 GENERAL SYNTHESIS.
with, the inconstant ones, with the result of bringing the still more constant relations into view; the progress must be from narrow generalizations to wider and wider ones. And this we know, d posteriori, to be the law which the progress conforms to.
§ 158. These explanations will at once show why the increase of the correspondence in generality is scarcely dis- cernible in any but the most intelligent creatures. Neces- sary as it is that there should be a great advance in the speciality of the correspondences to produce the requisite separation of attributes; and necessary as yet further advance in specialization is to bring into view the constantly-related attributes as distinguished from the inconstantly-related ones; it is only when that developed speciality of corre- spondence characterizing superior creatures is reached, that progress in generality of correspondence can begin. Hence the fact that while the higher mammals undoubtedly display some generalities of correspondence of the least abstract kind, it is only in the human race that this species of adjustment of inner to outer relations becomes conspicuous.
Human progression, however, exhibits to us, under this as under previous aspects, an immense increase in the har- mony between the organism and its environment. Perhaps in no respect is the increasing correspondence wrought out by civilization more conspicuous than in the growth of generalizations, ever more numerous and more compre- hensive. The enormous expansion of science which these latter ages have witnessed, mainly consists in the union of many particular truths into general truths, and in the union of many general truths into truths still more general. Illus- trations are needless; for the proposition is familiar and admitted by all. It is enough simply to point to this great phenomenon as one of the many forms of the evolution we are tracing out.
A mere mention, too, of the fact that the generalizations of THE CORRESPONDENCE AS INCREASING IN GENERALITY. 349 science immensely advance the arts, and through, the arts minister to human welfare,, will serve to show that increase of the correspondence in generality, like its other modes of increase, makes possible a greater duration of life. And a like brief reference to the concentration of thoughts and complexity of conceptions, which these wider generaliza- tions imply, will sufficiently indicate the higher degree of Hie which accompanies this greater length of Life, CHAPTER VUL THE CORRESPONDENCE AS INCREASING IN COMPLEXITY.
§ 159. Another change in.our stand-point affords us sa view of progressing vitality which, though not the same in range with foregoing views, has much in common with them. As we saw that the extensions of the correspondent in Space and in Time, are partly reciprocal and partly not so — as we saw that increase of the correspondence in Speciality, while to some degree comprised under the exten- sions in Space and Time, includes very much beside; so we shall see that while, throughout a certain range of cases, growing Complexity is the same thing as growing Speciality, yet neither includes all that the other does. Much of the early advance in Speciality does not imply advance in Com- plexity; and the higher forms of the advance in Complexity cannot without straining be comprehended under advance in Speciality.
§ 160. Wherever we find nothing but a greater ability to discriminate between varieties of the same simple pheno- menon, there is increased speciality of correspondence with- out increased complexity. It is thus with the progress from an eye that appreciates a difference between light and darkness, to one that appreciates degrees of difference be- tween them, and afterwards to one that appreciates differ- ences of colour and degrees of colour. It is thus with the THE CORRESPONDENCE AS INCREASING IN COMPLEXITY. 351 progress from the power of distinguishing a few strongly - contrasted smells or tastes, to the power of distinguishing- many slightly-contrasted smells or tastes. It is thus with the progress from that lowest form of hearing shown by a response to any violent tremor of the surrounding fluid, to those higher forms of it in which differences of loudness are recognized, and, by and by, differences of pitch and timbre. The insect which lays its eggs only on a plant having a particular odour, or the bird which is alarmed by a tone of a certain pitch but not by a tone of another, shows an adjustment of inner to outer relations equally simple with that shown by the snail which withdraws into its shell on being touched. Though the stimulus responded to is more special, it is not more complex. In each case a single undecoropo sable sensation is followed by certain muscular actions; and though these muscular actions are more intri- cate in the higher creatures than in the lower, yet the relation between antecedents and consequents is very nearly, if not quite, of the same order. But where tho stimulus responded to consists, not of a single sensation but of several, or where the response is not one action but a group of actions, the increase in speciality of correspondence results from an increase in its complexity.
The development of vision repeatedly illustrates this. When, after that response to tiie habitual relation between opacity and solidity, which is first established, there arises a response to the relauon oetween. solidity and power to reflect light — when differences in the amounts and qualities of reflected light come to be recognized in connexion with differences of bulk — when, there is acquired an ability to identify objects by form, as well as by colour and size con- joined; it is manifest that each successive stage implies the appreciation of larger clusters of attributes. The impres- sion received by the organism from each object is a more complex impression — is increasingly heterogeneous. And when not only colour, size, and shape become cognizable, 352 GENERAL SYNTHESIS.
but also direction in space, distance in space, motion, kind of motion, direction of motion, velocity of motion— when, as by a falcon swooping on its quarry, all these external relations are simultaneously responded to; it is clear that the guiding perception must be compounded of many ele- ments. There is no need to dwell on this truth as further exemplified during the evolution of the other senses; nor to trace up in detail that yet higher com- plexity which results when the several senses are employed together. A single extreme case will suffice. If we re- member how a mineralogist, in identifying a mass of matter as of a kind fitted for a certain use, examines its crystal- line form, its colour, texture, hardness, cleavage, fracture, 'degree of transparency, lustre, specific gravity, taste, smell, fusibility, magnetic and electric properties, &c., and is de- cided in his conduct by all these taken together; it will be obvious that throughout the higher range of cases, increase in the speciality of the correspondence involves increase in its complexity.
§ 161. But, as already hinted, we eventually rise to an order of correspondences in which the speciality and the complexity are no longer co-ordinate. A further advance in speciality is achieved by a more than proportionate advance in complexity. Let us look at an example or two- The archer who points his arrow, not at the object he seeks to hit, but above it, and who varies the angle of elevation according as the object is far or near, exhibits something more than a special response to special stimuli; for his procedure implies consciousness of the fact that bodies projected through the air descend towards the Earth, and that the amount of their descent has some relation to the distance traversed. Besides a correspondence with certain perceived relations in the environment, there is implied a correspondence with the law of certain other relations, not then present to the senses. Again, the engineer who erects TEE CORRESPONDENCE AS INCREASING IN COMPLEXITY. 353 a suspension-bridge competent to bear a specified strain, is guided less by his inspection and measurement of the river to be crossed, than by his knowledge of the strength of wrought iron, of the properties of the catenarian curve, of the composition of forces — his acquaintance with the uni- versal truths of number, geometry, and mechanics. In these cases the complexity of the correspondence is greatly in excess of the speciality. To bring out this fact by a contrast: — It might fairly be said that the Indian fish which catches insects flying over the surface by hitting them wittt jets of water, exhibits an adjustment of inner to outer rela- tions as special as that shown by the archer; but consider- ing that in the fish, nothing more is implied than an auto- matic connexion between certain visual impressions and certain muscular contractions, it cannot be held that there is anything like the same complexity of correspondence. Similarly, though the strength of a spider's web may be as specially adjusted to the demands to be made upon it, as is that of the engineer's suspension-bridge; yet there is no comparison between the two adjustments in respect of the variety and elaborateness of the actions by which they are achieved.
What constitutes this excess of complexity? It is con- stituted by the addition of generalities to specialities. Bach of these higher correspondences displaying what we call rationality, implies an adjustment ol inner relations not simply to the particular outer relations perceived, but to sundry general relations not then perceived, but established by previous experience. And as we advance to corre- spondences of still greater complexity, we see that their leading characteristic is the increasing number of gene- ralizations recognized, and involved in the process of ad- justment. Indeed, the highest achievements of science, as exemplified in astronomy, show us that an exact adapta- tion of the actions of the organism to special actions in the environment, supposes a pre-establishnaent of general re- 354 GENERAL SYNTHESIS.
lations in the organism, parallel to all those general rela- tions in the environment which, these special actions imply.
^ 162. There seems no place fitter than this, for drawing nttention to the important fact that an approximately-con- stant ratio is maintained between the impressibilities and the aciivih'es of the organism, in so far as their complexity is concerned. In the lowest animal types we see a touch followed by a withdrawal of the part touched — a single stimulus followed by a single motion. Gradually as we ascend, abilities to receive increasingly-complicated impres- sions, and to perform increasingly-complicated actions pre- sent themselves. And the truth here to be observed is, that the heterogeneity of the stimuli which can be appre- ciated is in general proportionate to the heterogeneity of the changes which can be displayed.
Note, first, that survival of the fittest ensures this con- nexion. As every advance consists in the adjustment of some further internal relation to some further external rela- tion; and as the ability to recognize the external relation is useless unless there is an ability to modify the conduct appropriately; it is clear that for the better preservation of life, the passive and active elements of the correspondence must progress together. A power to perceive the direction and distance of an object must be accompanied by a power to speciahze the movements; otherwise it can be of no service. The recognition of certain forms, colours, and SteH i fT of/rnetr win not prevent <^™*ion unless,t „ followed by such quick acts, such doublings, sho™ ^r?e enemy m^ be dnded by. Discrimination shown in the choice of materials for its nest, is so much THE CORRESPONDENCE AS INCREASING IN COMPLEXITY. 355 where it must on tie average happen that each additional differentiation of the perceptions, opening the way for an additional differentiation of the actions, fails to benefit the species, and therefore fails to be established in the species unless there goes along with it an additional differentiation of the actions.
This connexion between progress in the impressibilities and progress in the activities, is, indeed,, otherwise necessi- tated; for they so act and react that the advance of either involves the advance of both. The general relation between irritability and contractility, which, in the lowest types of animal life, constitute one indivisible phenomenon, is a relation which the regulative and the operative divisions of the organism maintain throughout all their complications. They are co-ordinate in their origin; they are co-ordinate in their manifestations; they are co-ordinate in their evolution.
This truth becomes conspicuous when we contemplate the two functions under their most general forms — sensation and motion. Given an organism with certain sensory and motor faculties, what will happen from the increase of •either? Higher powers of motion and locomotion mast bring the organism into relation with a greater number of objects; and must therefore multiply its impressions. Higher impressibility must subject the organism to more frequent stimuli to action; and so must multiply its motions and locomotions. Again, varied activities entail variety a-mong the relations in which a creature puts itself towards surrounding things; and hence entail variety among the modes in which surrounding things affect it. Conversely, the more various the impressions receivable from surround- ing things, the greater must be the number of modifications in the stimuli given to the motor faculties; and hence, the greater must be the tendency towards modified actions in the motor faculties. Thus the progress of each is involved with the progress o£ the other, in respect both of activity and complexity.
GB5TEEAL SYNTHESIS.
This inevitable simultaneity in the development of tho directive and executive faculties, will, however, be most dearlv seen on analyzing a few cases. Take as one, the ability to recognize direction in space. At first this seems to implv development of the sensitive part of the nature only: an expansion of the retina sufficiently great to admit of its components being separately affected by images falling on them. But a little consideration shows that something more is required than ability to perceive differ- ences between the positions of images on the visual tract. Taken alone,, these differences are meaningless. They como to have meaning only when they are severally connected in. the organism with those differences of motion required to bring its surface into contact with the things seen. Mere ocular impressions do not of themselves give ideas of space. Such, ideas are products of a growing experience which proves that these impressions are due to objects that can be touched by particular muscular adjustments. Direction, therefore, cannot be perceived until there is a motor appa- ratus sufficiently developed to effect specialized movements. Consequently, the ability to perceive direction and the ability to take advantage of the perception, are necessarily connate. The recognitions of distances, of velocities, of bulks, of shapes, obviously imply the like conditions. So, too, is ifc with the variations of surfaces indicated by lights and : these variations have to be disclosed by corre- sponding variations in the adjustments of the muscles, before lights and shades can be interpreted. No definite idea of weight, as connected with visual appearances, can be arrived at until there is a power of lifting, either by jaws or limbs Nor can degrees of hardness and unlikenesses of texture be perceived in surrounding objects, faster than the organs are perfected. Indeedj as s even more than above alleged; for besides being required for interpretation of impressions, nauscular all i* TEE COIifcESPOXDENCE AS INCREASING- IN COMPLEXITY. 357