with it, it was in no condition to fulfil its function, and people would not have been slow to perceive it: failures, being infinitely more frequent than successes, would have quickly shown them that they were following a false route, and religion, shaken at each instant by these repeated contradictions, would not have been able to survive. It is undeniably true that errors have been able to perpetuate themselves in history; but, except under a union of very exceptional circumstances, they can never perpetuate themselves thus unless they were _true practically_, that is to say, unless, without giving us a theoretically exact idea of the things with which they deal, they express well enough the manner in which they affect us, either for good or for bad. Under these circumstances, the actions which they determine have every chance of being, at least in a general way, the very ones which are proper, so it is easily explained how they have been able to survive the proofs of experience.[164] But an error and especially a system of errors which leads to, and can lead to nothing but mistaken and useless practices, has no chance of living. Now what is there in common between the rites with which the believer tries to act upon nature and the processes by which science has taught us to make use of it, and which we now know are the only efficacious ones? If that is what men demanded of religion, it is impossible to see how it could have maintained itself, unless clever tricks had prevented their seeing that it did not give them what they expected from it. It would be necessary to return again to the over simple explanations of the eighteenth century.[165]