Near the beginning of On the Incarnation: Saint Athanasius (Popular Patrictics Series), Athanasius reviews various theories concerning the origin of the world. It cannot be the case that matter existed eternally, since that would be a limit on God. It also cannot be the case that the world is self-organized, as the Epicureans believed. If it were, Athanasius says, there would be no distinctions among things:
“If things had come into being in this automatic fashion, instead of being the outcome of Mind, though they existed, they would all be uniform and without distinction. In the universe everything would be sun or moon or whatever it was, and in the human body the whole would be hand or eye or foot.” Obviously, this is not the world we know: “the sun and the moon and the earth are all different things, and even within the human body there are different members, such as food and hand and head.” Difference “argues not a spontaneous generation but a prevenient cause.”
An intriguing argument, but the force is obscure. Why must difference be the product of a mind? Perhaps the implied argument is something like this: Like produces like; if there was originally one thing, it could only have generated more of the same. Perhaps the best way to read it is to see it as a form of argument from design (Athanasius ends the paragraph by speaking of God as “Designer and Maker of all”). Difference is a feature of design, and design requires a a designer. Athanasius might be operating with the implicit judgment that the differences evident in the world are harmonious with one another; it is not difference per se but the harmony of difference that argues for a creative mind.