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.