One can hardly think without terror of the innumerable beings which have lived on the worlds now lost, of all the leading spirits who have thought, acted, guided humanity in the path of progress, light, and liberty. One cannot think of Platos, Pascals, and Newtons of the vanished worlds without asking what has become of them. It is easy to reply that that is nothing, that they died as they were born, that all is dust and returns to dust. It is an easy answer, but it is not satisfying. * * * * * Certainly, nobody can be so foolish as to claim to have found a solution of the great mystery. For treating those profound problems of eternity and infinity, we are about in the position of ants attempting to gain a knowledge of the history of France. In spite of all their mental gifts, which have indeed been fully recognised, in spite of their goodwill, their gallant attempts and all their efforts, it is quite probable that they would not get beyond the history of their ant-heap and would not arrive at any reasonable conclusions concerning human beings and their affairs. To them, naturally, the proprietors of the woods and fields are the ants, and the plant-lice domesticated by them. And the parasites of the Earth are those inedible insects which interfere with them. Do they know that birds exist? It is doubtful. As regards men, they do not know of their existence, though it may be that the ants in civilised countries have in their antennal language an expression corresponding to the idea of “sugar-maker,” or cook, or confectioner, or for some implacable enemy such as a gardener. But even if they suspected our existence, they could not form any idea about the human race or its history but--the ideas of ants. * * * * * It would no doubt be as useless as it is foolish to lose ourselves in the nebulosity of metaphysics to attain a solution which will escape us for ever. But it is no doubt a proper subject for the exercise of our mental faculties to think of this particular aspect of creation: _Time_; to think that from all eternity earths inhabited like ours have floated in the light of their suns, that from all eternity there have been humanities enjoying the pleasures of life, and that from all eternity the end of the world has sounded on the hoary timepiece of destiny, burying in turn the universes and their inhabitants in the tomb of annihilation and oblivion. For it is impossible for us to conceive a commencement which was not preceded by an eternity of inaction, and as far as the observational sciences can take us, they show us forces in perpetual activity. If infinite space dazzles us by its limitless immensity, an eternity without a beginning and without end arises, still more formidable perhaps, before our terrified gaze. The voices of the past speak to us from the abyss: they speak of the future. The past of extinct worlds is the _future_ of the earth.