Passing from this simplest case of co-operation to a case not quite so simple—a case in which the homogeneity is incomplete—let us ask how a member of the group may be led without dissatisfaction to expend effort in achieving a benefit which, when achieved, is enjoyed exclusively by another? Clearly he may do this on condition that the other shall afterward expend a like effort, the beneficial result of which shall be similarly rendered up by him in return. This exchange of equivalents of effort is the form which social co-operation takes while yet there is little or no division of labor, save that between the sexes. For example, the Bodo and Dhimals "mutually assist each other for the nonce, as well in constructing their houses as in clearing their plots for cultivation." And this principle—I will help you if you will help me—common in simple communities where the occupations are alike in kind, and occasionally acted upon in more advanced communities, is one under which the relation between effort and benefit, no longer directly maintained, is maintained indirectly. For whereas when men's activities are carried on separately, or are joined in the way exemplified above, effort is immediately paid for by benefit, in this form of co-operation the benefit achieved by effort is exchanged for a like benefit to be afterward received when asked for. And in this case as in the preceding case, co-operation can be maintained only by fulfillment of the tacit agreements. For if they are habitually not fulfilled, there will commonly be refusal to give aid when asked; and each man will be left to do the best he can by himself. All those advantages to be gained by union of efforts in doing things that are beyond the powers of the single individual, will be unachievable. At the outset, then, fulfillment of contracts that are implied if not expressed, becomes a condition to social co-operation, and therefore to social development.
From these simple forms of co-operation in which the labors men carry on are of like kinds, let us turn to the more complex forms in which they carry on labors of unlike kinds. Where men mutually aid in building huts or felling trees, the number of days' work now given by one to another is readily balanced by an equal number of days' work afterward given by the other to him. And no estimation of the relative values of the labors being required, a definite understanding is little needed. But when division of labor arises—when there come transactions between one who makes weapons and another who dresses skins for clothing, or between a grower of roots and a catcher of fish—neither the relative amounts nor the relative qualities of their labors admit of easy measure; and with the multiplication of businesses, implying numerous kinds of skill and power, there ceases to be anything like manifest equivalence between either the bodily and mental efforts set against one another, or between their products. Hence the arrangement cannot now be taken for granted, as while the things exchanged are like in kind: it has to be stated. If A allows B to appropriate a product of his special skill, on condition that he is allowed to appropriate a different product of B's special skill, it results that as equivalence of the two products cannot be determined by direct comparison of their quantities and qualities, there must be a distinct understanding as to how much of the one may be taken in consideration of so much of the other.
Only under voluntary agreement, then, no longer tacit and vague, but overt and definite, can co-operation be harmoniously carried on when division of labor becomes established. And as in the simplest co-operation, where like efforts are joined to secure a common good, the dissatisfaction caused in those who, having expended their labors do not get their shares of the good, prompts them to cease co-operating; as in the more advanced co-operation, achieved by exchanging equal labors of like kind expended at different times, aversion to co-operate is generated if the expected equivalent of labor is not rendered; so in this developed co-operation, the failure of either to surrender to the other that which was avowedly recognized as of like value with the labor or product given, tends to prevent co-operation by exciting discontent with its results. And evidently, while antagonisms thus caused impede the lives of the units, the life of the aggregate is endangered by diminished cohesion.
§ 53. Beyond these comparatively direct mischiefs, special and general, there have to be noted indirect mischiefs. As already implied by the reasoning in the last paragraph, not only social integration but also social differentiation, is hindered by breach of contract.
In Part II of the Principles of Sociology, it was shown that the fundamental principles of organization are the same for an individual organism and for a social organism; because both consist of mutually dependent parts. In the one case as in the other, the assumption of unlike activities by the component members, is possible only on condition that they severally benefit in due degrees by one another's activities. That we may the better see what are the implications in respect of social structures, let us first note the implications in respect of individual structures.
The welfare of a living body implies an approximate equilibrium between waste and repair. If the activities involve an expenditure not made good by nutrition, dwindling follows. If the tissues are enabled to take up from the blood enriched by food, fit substances enough to replace those used up in efforts made, the weight may be maintained. And if the gain exceeds the loss, growth results.
That which is true of the whole in its relations to the external world, is no less true of the parts in their relations to one another. Each organ, like the entire organism, is wasted by performing its function, and has to restore itself from the materials brought to it. If the quantity of materials furnished by the joint agency of the other organs is deficient, the particular organ dwindles. If they are sufficient, it can maintain its integrity. If they are in excess, it is enabled to increase. To say that this arrangement constitutes the physiological contract, is to use a metaphor which, though not true in aspect is true in essence. For the relations of structures are actually such that, by the help of a central regulative system, each organ is supplied with blood in proportion to the work it does. As was pointed out (Principles of Sociology, § 254) well-developed animals are so constituted that each muscle or viscus, when called into action, sends to the vaso-motor centers through certain nerve-fibers, an impulse caused by its action; whereupon, through other nerve-fibers, there comes an impulse causing dilatation of its blood-vessels. That is to say, all other parts of the organism, when they jointly require it to labor, forthwith begin to pay it in blood. During the ordinary state of physiological equilibrium, the loss and the gain balance, and the organ does not sensibly change. If the amount of its function is increased within such moderate limits that the local blood-vessels can bring adequately-increased supplies, the organ grows: beyond replacing its losses by its gains, it makes a profit on its extra transactions; so being enabled by extra structures to meet extra demands. But if the demands made on it become so great that the supply of materials cannot keep pace with the expenditure, either because the local blood-vessels are not large enough, or for any other reason, then the organ begins to decrease from excess of waste over repair: there sets in what is known as atrophy. Now, since each of the organs has thus to be paid in nutriment for its services by the rest, it follows that the due balancing of their respective claims and payments is requisite, directly for the welfare of each organ, and indirectly for the welfare of the organism. For in a whole formed of mutually dependent parts, anything which prevents due performance of its duty by one part reacts injuriously on all the parts.
With change of terms these statements and inferences hold of a society. That social division of labor which parallels in so many other respects the physiological division of labor, parallels it in this respect also. As was shown at large in the Principles of Sociology, Part II, each order of functionaries and each group of producers, severally performing some action or making some article not for direct satisfaction of their own needs but for satisfaction of the needs of fellow-citizens in general, otherwise occupied, can continue to do this only so long as the expenditures of effort and returns of profit are approximately equivalent. Social organs, like individual organs, remain stationary if there come to them normal proportions of the commodities produced by the society as a whole. If because the demands made on an industry or profession are unusually great, those engaged in it make excessive profits, more citizens flock to it and the social structure constituted by its members grows; while decrease of the demands and therefore of the profits, either leads its members to choose other careers or stops the accessions needful to replace those who die, and the structure dwindles. Thus is maintained that proportion among the powers of the component parts which is most conducive to the welfare of the whole.
And now mark that the primary condition to achievement of this result is fulfillment of contract. If from the members of any part payment is frequently withheld, or falls short of the promised amount, then, through ruin of some and abandonment of the occupation by others, the part diminishes; and if it was before not more than competent to its duty, it now becomes incompetent, and the society suffers. Or if social needs throw on some part great increase of function, and the members of it are enabled to get for their services unusually high prices; fulfillment of the agreements to give them these high prices, is the only way of drawing to the part such additional number of members as will make it equal to the augmented demands. For citizens will not come to it if they find the high prices agreed upon are not paid.
Briefly, then, the universal basis of co-operation is the proportioning of benefits received to services rendered. Without this there can be no physiological division of labor; without this there can be no sociological division of labor. And since division of labor, physiological or sociological, profits the whole and each part; it results that on maintenance of the arrangements necessary to it, depend both special and general welfare. In a society such arrangements are maintained only if bargains, overt or tacit, are carried out. So that beyond the primary requirement to harmonious co-existence in a society, that its units shall not directly aggress on one another; there comes this secondary requirement, that they shall not indirectly aggress by breaking agreements.