Nevertheless, whether actually existing or only approached, we must here recognize as hypothetically possible a state in which these primary moral laws are conformed to; for the purpose of observing, in their uncomplicated forms, what are the negative conditions to harmonious social life. Whether the members of a social group do or do not co-operate, certain limitations to their individual activities are necessitated by their association; and, after recognizing these as arising in the absence of co-operation, we shall be the better prepared to understand how conformity to them is effected when co-operation begins. § 52. For whether men live together in quite independent ways, careful only to avoid aggressing; or whether, advancing from passive association to active association, they co-operate, their conduct must be such that the achievement of ends by each shall at least not be hindered. And it becomes obvious that when they co-operate there must not only be no resulting hinderance but there must be facilitation; since, in the absence of facilitation, there can be no motive to co-operate. What shape, then, must the mutual restraints take when co-operation begins? or rather--What, in addition to the primary mutual restraints already specified, are those secondary mutual restraints required to make co-operation possible? One who, living in an isolated way, expends effort in pursuit of an end, gets compensation for the effort by securing the end, and so achieves satisfaction. If he expends the effort without achieving the end there results dissatisfaction. The satisfaction and the dissatisfaction are measures of success and failure in life-sustaining acts; since that which is achieved by effort is something which directly or indirectly furthers life, and so pays for the cost of the effort; while if the effort fails there is nothing to pay for the cost of it, and so much life is wasted. What must result from this when men's efforts are joined? The reply will be made clearer if we take the successive forms of co-operation in the order of ascending complexity. We may distinguish as homogeneous co-operation (1) that in which like efforts are joined for like ends that are simultaneously enjoyed. As co-operation that is not completely homogeneous we may distinguish (2) that in which like efforts are joined for like ends that are not simultaneously enjoyed. A co-operation of which the heterogeneity is more distinct is (3) that in which unlike efforts are joined for like ends. And lastly comes the decidedly heterogeneous co-operation (4) that in which unlike efforts are joined for unlike ends.