The incorruptibility of the heaven has been ascribed to its containing within its breast all things,[201] and to the non-existence of any other thing into which it could change, as well as to the impossibility of its meeting anything exterior that could destroy it. These theories would indeed, in a reasonable manner, explain the incorruptibility of heaven considered as totality, and universe; but would fail to explain the perpetuity of the sun and of the other stars which are parts of heaven, instead of being the whole universe, as is the heaven. It would seem more reasonable that, just like the fire and similar things, the stars, and the world considered as universe would possess a perpetuity chiefly of form. It is quite possible that the heaven, without meeting any destructive exterior thing, should be subjected to a perpetual destruction such that it would preserve nothing identical but the form, from the mere mutual destruction of its parts. In this case its substrate, being in a perpetual flux, would receive its form from some other principle; and we would be driven to recognize in the universal living Organism what occurs in man, in the horse, and in other animals; namely, that the man or horse (considered as species) lasts forever, while the individual changes. (According to this view, then) the universe will not be constituted by one ever permanent part, the heaven, and another ceaselessly changing one, composed of terrestrial things. All these things will then be subject to the same condition though they might differ by longer or shorter duration, since celestial bodies are more durable. Such a conception of the perpetuity characteristic of the universe and its parts contains less ambiguity (than the popular notion), and would be freed from all doubt if we were to demonstrate that the divine power is capable of containing the universe in this manner. The theory that the world contains something perpetual in its individuality would demand not only a demonstration that the divine volition can produce such an effect, but also an explanation why certain things (according to that theory) are always identical (in form and individuality), while other things are identical only by their form. If the parts of the heaven alone remained identical (by their individuality), all other things also should logically remain (individually) identical.
REJECTION OF THE OPINION OF HERACLITUS.
2. An admission that the heaven and the stars are perpetual in their individuality, while sublunary things are perpetual only in their form, would demand demonstration that a corporeal being can preserve its individuality as well as its form, even though the nature of bodies were a continual fluctuation. Such is the nature that the physical philosophers,[202] and even Plato himself, attribute not only to sublunar bodies, but even to celestial ones. "For," asks (Plato[203]), "how could corporeal and visible objects subsist ever immutable and identical with themselves?" (Plato) therefore admits the opinion of Heraclitus that "the sun itself is in a state of perpetual becoming (or, growth)."[204]
ARISTOTLE HAS TO DEPEND ON QUINTESSENCE.
On the contrary, in the system of Aristotle, the immutability of the stars is easily explained, but only after accepting his theory of a fifth element (the quintessence[205]). If, however, it be rejected, it would be impossible to demonstrate that the heaven, let alone its parts, the sun and the stars, do not perish, while (as Aristotle does) we regard the body of the heaven as being composed of the same elements as terrestrial animals.
PLOTINOS'S VIEWS SUPPORTED BY THE HEAVEN'S POSSESSION OF THE SOUL AND BODY.
As every animal is composed of soul and body, the heaven must owe the permanence of its individuality to the nature either of its soul, or of its body; or again, to that of both. On the hypothesis that its incorruptibility is due to the nature of its body, the Soul's only function will be to animate it (by uniting with the body of the world). On the contrary hypothesis that the body, by nature corruptible, owes its incorruptibility exclusively to the Soul, there is need of demonstration that the state of the body does not naturally oppose this constitution and permanence (for, naturally constituted objects admit of no disharmony); but that, on the contrary, here matter, by its predisposition, contributes to the accomplishment of the divine volition.
FLUCTUATION NEED NOT INTERFERE WITH CONTINUANCE.
3. (It might however be objected) that the body of the world could not contribute to the immortality of the world, since the body itself fluctuates perpetually. But this fluctuation does not take place in an outward direction, while the body (of the world) remains ever the same because this fluctuation occurs so entirely within the world that nothing issues therefrom. The world therefore could neither increase nor diminish, nor further grow old. (As proof of this we may) consider how, from all eternity, the earth constantly preserves the same shape and mass; similarly, the air never diminishes, any more than the water. The changes within them do not affect the universal living Organism. Even we human beings subsist a long while, in spite of the perpetual change of our constituent parts, and though some of these parts even issue from the body. So much the more will the world's nature, from which nothing issues, sufficiently harmonize with the nature of the universal Soul to form along with her an organism which ever remains the same, and subsists for ever.