As all the best critics of philosophy have pointed out,[18] any philosophical system which admits such a great contradiction fails utterly to furnish workable standards of order in the universe, and so falls short of achieving philosophy's first aim. We must either believe with the scholastics that intelligence rules, or we must believe, with Haeckel, that all things happen in obedience to invariable natural laws. We cannot believe both. A great many men, toward the beginning of the 90's, began to notice this fatal defect in Darwin's idea of human progress. In 1891 one of them pointed out the conclusion toward which it inevitably led.[19] If we admitted, he said, that humanity had set at naught the law of natural selection, we must admit that civilization was working against nature's efforts to preserve the race, and that, in the end, humanity would perish. To put it more succinctly, man might defy the law of natural selection as much as he pleased, but he could never hope to set it aside. Soon or late, he would awaken to the fact that he remained a mere animal, like the rabbit and the worm, and that, if he permitted his body to degenerate into a thing entirely lacking in strength and virility, not all the intelligence conceivable could save him. Nietzsche saw all this clearly as early as 1877.[20] He saw that what passed for civilization, as represented by Christianity, was making such an effort to defy and counteract the law of natural selection, and he came to the conclusion that the result would be disaster. Christianity, he said, ordered that the strong should give part of their strength to the weak, and so tended to weaken the whole race. Self-sacrifice, he said, was an open defiance of nature, and so were all the other Christian virtues, in varying degree. He proposed, then, that before it was too late, humanity should reject Christianity, as the "greatest of all imaginable corruptions," and admit freely and fully that the law of natural selection was universal and that the only way to make real progress was to conform to it.