6. Granted, it may be urged, that these observations upon the nature of Substance are sound, we have not yet arrived at a statement of its essence. Our critic doubtless expects to see this "Sensible": but its essence, its characteristic being, cannot be seen.
Do we infer that fire and water are not Substance? They certainly are not Substance because they are visible. Why, then? Because they possess Matter? No. Or Form? No. Nor because they involve a Couplement of Matter and Form. Then why are they Substance? By existing. But does not Quantity exist, and Quality? This anomaly is to be explained by an equivocation in the term "existence."
What, then, is the meaning of "existence" as applied to fire, earth and the other elements? What is the difference between this existence and existence in the other categories? It is the difference between being simply- that which merely is- and being white. But surely the being qualified by "white" is the same as that having no qualification? It is not the same: the latter is Being in the primary sense, the former is Being only by participation and in a secondary degree. Whiteness added to Being produces a being white; Being added to whiteness produces a white being: thus, whiteness becomes an accident of Being, and Being an accident of whiteness.
The case is not equivalent to predicating white of Socrates and Socrates of white: for Socrates remains the same, though white would appear to have a different meaning in the two propositions, since in predicating Socrates of white we include Socrates in the [whole] sphere of whiteness, whereas in the proposition "Socrates is white" whiteness is plainly an attribute of Socrates.
"Being is white" implies, similarly, that Being possesses whiteness as an attribute, while in the proposition "whiteness is Being [or, is a being]" Being is regarded as comprising whiteness in its own extension.
In sum, whiteness has existence because it is bound up with Being and present in it: Being is, thus, the source of its existence. Being is Being on its own account, but the white is due to whiteness- not because it is "present in" whiteness, but because whiteness is present in it.
The Being of the Sensible resembles the white in not originating in itself. It must therefore be regarded as dependent for its being upon the Authentic Being, as white is dependent upon the Authentic Whiteness, and the Authentic Whiteness dependent for its whiteness upon participation in that Supreme Being whose existence is underived.