5. How can an essence be single in a multitude of souls? Either this one essence is entire in all souls, or this one and entire essence begets all souls while remaining (undiminished) in itself. In either case, the essence is single. It is the unity to which the individual souls are related; the essence gives itself to this multitude, and yet simultaneously the essence does not give itself; it can give of itself to all individual souls, and nevertheless remain single; it is powerful enough to pass into all simultaneously, and to be separated from none; thus its essence remains identical, while being present in a multitude of souls. This is nothing astonishing; all of science is entirely in each of its parts, and it begets them without itself ceasing to remain entire within itself. Likewise, a grain of seed is entire in each of its parts in which it naturally divides itself; each of its parts has the same properties as the whole seed; nevertheless the seed remains entire, without diminution; and if the matter (in which the seed resides) offer it any cause of division, all the parts will not any the less form a single unity. THIS MIRACLE IS EXPLAINED BY THE USE OF THE CONCEPTION OF POTENTIALITY. It may be objected that in science a part is not the total science. Doubtless, the notion which is actualized, and which is studied to the exclusion of others, because there is special need of it, is only partially an actualization. Nevertheless, in a latent manner it potentially comprises all the other notions it implies. Thus, all the notions are contained in each part of the science, and in this respect each part is the total science; for what is only partially actualized (potentially) comprises all the notions of science. Each notion that one wishes to render explicit is at one's disposition; and this in every part of the science that is considered; but if it be compared with the whole science, it seems to be there only potentially. It must not, however, be thought that the particular notion does not contain anything of the other notions; in this case, there would be nothing systematic or scientific about it; it would be nothing more than a sterile conception. Being a really scientific notion, it potentially contains all the notions of the science; and the genuine scientist knows how to discover all its notions in a single one, and how to develop its consequences. The geometrical expert shows in his demonstrations how each theorem contains all the preceding ones, to which he harks back by analysis, and how each theorem leads to all the following ones, by deduction. DIFFICULT AS THESE EXPLANATIONS ARE, THEY ARE CLEAR INTELLIGIBLY. These truths excite our incredulity, because here below our reason is weak, and it is confused by the body. In the intelligible world, however, all the verities are clear, and each is evident, by itself. SIXTH ENNEAD, BOOK NINE. Of the Good and the One. UNITY NECESSARY TO EXISTENCE OF ALL BEINGS.