When we do not know the truth of a thing, it is of advantage that there should exist a common error which determines the mind of man, as, for example, the moon, to which is attributed the change of seasons, the progress of diseases, etc. This is where natural reason brings us. And, since he cannot go on without this knowledge, I wish, before entering into larger studies of nature, that he consider nature for a serious and leisurely moment, as well as look on himself, and get to know the proportions between nature and man. The entire visible world is only an imperceptible speck in the ample bosom of nature. No idea can come close to imagining it.
Nature is an infinite sphere in which the center is everywhere, the circumference is nowhere.
Finally, it is the greatest sensible mark of God's omnipotence, that our imagination loses itself in that thought. But to offer him another astonishing prodigy, let him behold the tiniest things he knows of. I wish now to make him see therein a new abyss. I want to paint for him not only the visible universe, but all the imaginable immensity of nature within the confines of an atom. He is nothing in comparison with the infinite, and everything in comparison with nothingness, a middle term between all and nothing.