substances differ in their essential natures. These arguments therefore remain dependent on the claim that substances are all alike, which the disputant rejects. Indeed, he may say that their differences are self-evident.

The claim that they are all alike contradicts sensory experience and self-evident knowledge. We know that the essential nature of water differs from that of fire, that the essential nature of gold differs from that of bread, and that the essential nature of blood differs from that of earth, and so forth. What two things share in being substances is that they both subsist in themselves, are spatially localized, or can bear attributes. This is a sharing of certain attributes, not of the essential reality that bears those attributes.

Third:

If by saying, “He is a substance like other substances,” he means that He is identical in His essential reality to every substance, and that whatever is possible for any substance is possible for Him, no rational person says this.

Rather, the disputant means that He subsists in Himself, is spatially localized, or possesses some similar characteristic. He maintains that sharing such a characteristic is like sharing the fact that each is living and subsists in itself, and so forth. The dispute thus remains over whether what these people call a substance entails that all its instances are alike.

They say: “No; rather, it is a term whose instances differ.” The dispute also concerns the claim of one party that sharing spatial localization, in its technical sense, entails sameness in essential reality—a claim the other party denies.