Select Works, Section 245 (part 2)

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.