Where a public necessity has been well supplied by individual action, I should leave it in the hands of individuals; but not otherwise. I did not object to the Poor Law on the broad ground that it took the place of private action, but because its own action was mischievous. I should try every case on its merits, and be guided to interfere or not interfere by the known results of the existing policies.” In so speaking, Malthus would no doubt have justified his own consistency. But the modern reader might justly reply to Malthus, that we have often to judge tendencies as well as results, and experience becomes then an uncertain guide; he might complain that Malthus himself is sometimes led to judge both of them by a half-acknowledged supplementary principle of the balance of classes and safety of the mean, which can be applied in a way very unfavourable to popular rights. He might urge that the apparent success of an institution might have been due to a concurrent cause that cancelled its defects, and we cannot always pronounce on its merits from experience of it. How can experience help us unless we have the key to its interpretation? Without such a key nothing would be so false as facts except figures. In human politics mere survival is seldom the test of fitness. If we compare the state to an organism and convert our simile into a rule of judgment, we may say that, when each part has its function and contributes to the efficiency of the whole, the body politic is well; when any part does not, there is need of the doctor or surgeon. This figure seems to give us a key for the interpretation of social experience; but unhappily the figure itself needs an interpreter.[813] If we interpret organism as the ideal union of members in one body, it ceases to be a simile, for the body politic is not merely like this union,—it is the best example of it. For in the body politic the general life is the source of all individual energy, and at the same time the individual members are continually paying back the debt, by an active sympathy and conscious union with the commonwealth, to which the commonwealth in its turn owes all its collective energy; the citizen is nothing without his state, or the state without its citizens. This is to make the figure useful, by making it change places with the thing prefigured. So long as the same idea is grasped in both, their relation in rhetoric need not affect us.