Dare we hope that humanity will one day renounce these monstrous follies and that they will become altogether impossible? To this question, if we wish to meet it at its source, I see but one reply, which I have already given elsewhere and which I will here recapitulate and complete, namely, that we are engulfed in a universe which has no more limit in time than it has in space, which had no beginning, as it will have no end, and which has behind it as many myriads of myriads of years as it discovers ahead of it. Yesterday’s eternity and to-morrow’s are precisely identical. All that the universe is going to do it must have already done, for it has had as many opportunities of doing so as it will ever have. All the things that it has not done are things which it will never be able to do, because nothing will be added, in space or time, to what it has already possessed in space or time. It has necessarily made in the past all the efforts and all the experiments which it will make in the future; and all that has gone before, having been subject to the same chances, is perforce the same as all that is to follow. 2 It is probable, therefore, that there was once an infinity of worlds similar to our own, even as it is likely that there is an infinity of such similar worlds at present, the infinity of space being comparable with that of time. These coincidences, however difficult for us to picture, must inevitably occur and recur in the immeasurable and the innumerous in which we are immersed, that is, unless the infinity of possible combinations be less unlimited than those of time and space. This is where our capacity of imagination halts, for it is easier for us to conceive the infinities of space and time than the infinity of combinations. To obtain some idea of the latter, we should have to understand the substance and the nature, the laws and the forces, in a word, the whole riddle of existence. None the less is it true that this possible infinity of combinations is our only hope; without it there would be nothing more to expect of a universe which obviously would have tried and exhausted everything before our coming.