  In chapter 3 Anselm argues that all existing things exist through some one thing. Every existing thing, he begins, exists either through something or through nothing. But of course nothing exists through nothing, so every existing thing exists through something. There is, then, either some one thing through which all existing things exist, or there is more than one such thing. If there is more than one, either (i) they all exist through some one thing, or (ii) each of them exists through itself, or (iii) they exist through each other. (iii) makes no sense. If (ii) is true, then “there is surely some one power or nature of self-existing that they have in order to exist through themselves” (M 3); in that case, “all things exist more truly through that one thing than through the several things that cannot exist without that one thing” (M 3). So (ii) collapses into (i), and there is some one thing through which all things exist. That one thing, of course, exists through itself, and so it is greater than all the other things. It is therefore “best and greatest and supreme among all existing things” (M 3).