We must therefore include the heavenly bodies which we cannot see and concerning which we know very little. But here we encounter a very peculiar paradox. We know nothing about these invisible stars, and yet as far as our interests are concerned we know more about them than the others. For mathematics comes to our aid, and if we rely on the calculus of probabilities we arrive, as we shall see, at very clear results. Our Sun has created for itself, without counting the asteroids, a retinue of eight planets, which on account of their respective distances from the central body are placed in the most diverse conditions as regards temperature. Out of these eight planets one, the Earth, is undoubtedly inhabited, and two others, Mars and Venus, very probably. From the fact that the Sun has produced not one planet but eight, we can conclude that very probably the other suns or fixed stars have also produced one or several planets, and that those which escape from that law are the exception. We must also admit that among these stellar planets there may be some in such a condition and at such a distance from their central sun that organic life is possible on their surfaces. We shall make this calculation with figures so modest that we shall obtain results obviously below the truth. The number of stars revealed by a telescope of moderate power amounts to 10 millions. If we suppose that every star only has on an average one planet, we obtain already the considerable number of 10 million planets. It is true that with us three planets out of eight may be considered habitable, but let us suppose the proportion in the universe is only one in a hundred. We shall still have no less than a hundred thousand habitable planets. This number, evidently falling short of reality, makes already quite another figure compared with the three habitable worlds we had before. After that the universe no longer appears such a desert. There is nothing to hinder us from giving rein to our fancy and imagining on the one hand the strangest forms of life among the innumerable planets gravitating round the stars, and on the other hand thinking beings which surpass us considerably in intelligence and to whom our most difficult problems are as transparent as self-evident truths. The conclusion is that in all sorts of degrees we must see Life radiating into space and lighting up Infinity. REMARKS To this interesting study of Monsieur Scheiner we may add in the first instance that the question is still more complex, that we can consider the resources of Nature as infinite, and that “positive” science founded only upon our senses is quite insufficient, though it may be the only basis of our reasoning. It is through the eyes of the spirit that we must survey the universe.