13. Further, they must explain in what sense they hold that Matter tends to slip away from its form [the Idea]. Can we conceive it stealing out from stones and rocks or whatever else envelops it?
And of course they cannot pretend that Matter in some cases rebels and sometimes not. For if once it makes away of its own will, why should it not always escape? If it is fixed despite itself, it must be enveloped by some Ideal-Form for good and all. This, however, leaves still the question why a given portion of Matter does not remain constant to any one given form: the reason lies mainly in the fact that the Ideas are constantly passing into it.
In what sense, then, is it said to elude form?
By very nature and for ever?
But does not this precisely mean that it never ceases to be itself, in other words that its one form is an invincible formlessness? In no other sense has Plato's dictum any value to those that invoke it.
Matter [we read] is "the receptacle and nurse of all generation."
Now if Matter is such a receptacle and nurse, all generation is distinct from it; and since all the changeable lies in the realm of generation, Matter, existing before all generation, must exist before all change.
"Receptacle" and "nurse"; then it "retains its identity; it is not subject to modification. Similarly if it is" [as again we read] "the ground on which individual things appear and disappear," and so, too, if it is a "place, a base." Where Plato describes and identifies it as "a ground to the ideas" he is not attributing any state to it; he is probing after its distinctive manner of being.
And what is that?
This which we think of as a Nature-Kind cannot be included among Existents but must utterly rebel from the Essence of Real Beings and be therefore wholly something other than they- for they are Reason-Principles and possess Authentic Existence- it must inevitably, by virtue of that difference, retain its integrity to the point of being permanently closed against them and, more, of rejecting close participation in any image of them.
Only on these terms can it be completely different: once it took any Idea to hearth and home, it would become a new thing, for it would cease to be the thing apart, the ground of all else, the receptacle of absolutely any and every form. If there is to be a ceaseless coming into it and going out from it, itself must be unmoved and immune in all the come and go. The entrant Idea will enter as an image, the untrue entering the untruth.
But, at least, in a true entry?
No: How could there be a true entry into that which, by being falsity, is banned from ever touching truth?
Is this then a pseudo-entry into a pseudo-entity- something merely brought near, as faces enter the mirror, there to remain just as long as the people look into it?
Yes: if we eliminated the Authentic Existents from this Sphere nothing of all now seen in sense would appear one moment longer.
Here the mirror itself is seen, for it is itself an Ideal-Form of a Kind [has some degree of Real Being]; but bare Matter, which is no Idea, is not a visible thing; if it were, it would have been visible in its own character before anything else appeared upon it. The condition of Matter may be illustrated by that of air penetrated by light and remaining, even so, unseen because it is invisible whatever happens.
The reflections in the mirror are not taken to be real, all the less since the appliance on which they appear is seen and remains while the images disappear, but Matter is not seen either with the images or without them. But suppose the reflections on the mirror remaining and the mirror itself not seen, we would never doubt the solid reality of all that appears.
If, then, there is, really, something in a mirror, we may suppose objects of sense to be in Matter in precisely that way: if in the mirror there is nothing, if there is only a seeming of something, then we may judge that in Matter there is the same delusion and that the seeming is to be traced to the Substantial-Existence of the Real-Beings, that Substantial-Existence in which the Authentic has the real participation while only an unreal participation can belong to the unauthentic since their condition must differ from that which they would know if the parts were reversed, if the Authentic Existents were not and they were.