But how do you know this? If it has had a beginning, as geology and astronomy prove,[90] it will also have an end. This end, however, will not be an annihilation; it will simply be, as we have already pointed out, a transformation of matter. As for the problems, whether nature itself was created, and whether it is eternal, let us leave them to the discussion of heated theoricians, who are too blind to perceive that some questions it is wisest neither to affirm nor deny, but _to know how to ignore_. * * * * * The error, then, which we have been considering, destroys itself through its consequences. Let us admit, in effect, that our world--such as it is, just as it is--will last for ever. In that case what becomes of the power and travail of humanity? All they have accomplished are some slight changes of the terrestrial crust, barely sufficient, here and there, to modify the influences of climate. A limited number of men labour, it is true, for the progress and full development of transmissible thought. But even supposing that, in the course of centuries, humanity succeeds in comprehending, it can only _grow_ through the development of the faculties of all its members, and the due balance of all the social forces by means of liberty. Supposing that reason, united to science and conscience, should finally combine in one family the various tribes and peoples scattered over the earth's broad surface; do you indulge yourself in the hope of crossing the limits of the human organization, and establishing the royalty of man "through the interpretation and imitation of Nature?" Do you cherish the idea of penetrating, through the perfect union of all your intellectual forces, the mysteries of creation? No; you would never dare to form such a hope, to nourish such an idea, at least unless you felt that the earth (which you must first demonstrate) comprehends in itself the whole universe, that the humanity swarming on its surface is eternal, that every other creature is absolutely subordinate to it: in a word, that Man is all! But we know how limited is human power. We are not masters even of the mechanism of the body; the movements of organic life are independent of our will; we can neither command the stomach, the lungs, nor the heart: that marvellous process of absorption and elimination, that perpetual movement hither or thither which constitutes the essence of the assimilative function, goes on in us--as in all living beings, animal or vegetable--completely outside our sphere of activity. Then, without quitting our planet, how numerous are the movements which still escape the human will! * * * * *