Plotinus, as we have said, starts with the Aristotelian account of Matter; but by a process of dialectical manipulation, he gradually brings it into almost complete agreement with Plato’s conception; thus, as usual, mediating between and combining the views of his two great authorities. In the first place, he takes advantage of Aristotle’s distinction between intelligible and sensible Matter, to strip the latter of that positive and vital significance with which it had been clothed in the Peripatetic system. In the world of Ideas, there is an element common to all specific forms, a fundamental unity in which they meet and inhere, which may without impropriety be called their Matter. But this Matter is an eternal and divine substance, inseparably united with the fixed forms which it supports, and, therefore, something which, equally with them, receives light and life and thought from the central source of being. It is otherwise with sensible Matter, the common substance of the corporeal elements. This is, to use the energetic expression of our philosopher, a decorated corpse.[481] It does not remain constantly combined with any form, but is for ever passing from one to another, without manifesting a particular preference for any. As such, it is the absolute negation of Form, and can only be conceived, if at all, by thinking away every sensible quality. Neither has it any quantity, for quantity means magnitude, and magnitude implies definite figure. Aristotle opposed to each particular form a corresponding privation, and placed Matter midway between them. Plotinus, on the other hand, identifies Matter with the general privation of all forms. It is at this point that he begins to work his way back to the Platonic notion of Matter as simple extension. There must, after all, be something about Matter which enables it to receive every kind of quality and figure,—it must have some sort of mass or bulk, not, indeed, in any definite sense, but with an equal capacity for expansion and for contraction. Now, says Plotinus, the very indeterminateness of Matter is precisely the capacity for extension in all directions that we require. ‘Having no principle of stability, but being borne towards every form, and easily led about in all directions, it acquires the nature of a mass.’[482]