10. Further: If Matter were susceptible of modification, it must acquire something by the incoming of the new state; it will either adopt that state, or, at least, it will be in some way different from what it was. Now upon this first incoming quality suppose a second to supervene; the recipient is no longer Matter but a modification of Matter: this second quality, perhaps, departs, but it has acted and therefore leaves something of itself after it; the substratum is still further altered. This process proceeding, the substratum ends by becoming something quite different from Matter; it becomes a thing settled in many modes and many shapes; at once it is debarred from being the all-recipient; it will have closed the entry against many incomers. In other words, the Matter is no longer there: Matter is destructible.
No: if there is to be a Matter at all, it must be always identically as it has been from the beginning: to speak of Matter as changing is to speak of it as not being Matter.
Another consideration: it is a general principle that a thing changing must remain within its constitutive Idea so that the alteration is only in the accidents and not in the essential thing; the changing object must retain this fundamental permanence, and the permanent substance cannot be the member of it which accepts modification.
Therefore there are only two possibilities: the first, that Matter itself changes and so ceases to be itself, the second that it never ceases to be itself and therefore never changes.
We may be answered that it does not change in its character as Matter: but no one could tell us in what other character it changes; and we have the admission that the Matter in itself is not subject to change.
Just as the Ideal Principles stand immutably in their essence- which consists precisely in their permanence- so, since the essence of Matter consists in its being Matter [the substratum to all material things] it must be permanent in this character; because it is Matter, it is immutable. In the Intellectual realm we have the immutable Idea; here we have Matter, itself similarly immutable.