Furthermore, anyone who says, “These observable substances are alike in their reality, but the agent who acts by choice has endowed each with attributes that distinguish it from the others,” thereby implies that they have a reality stripped of all the attributes in which they differ. Observable water would thus have a reality other than this observable water, and observable fire a reality other than this observable fire. What distinguishes water from fire would be something accidental to that reality, neither an essential attribute nor an inseparable one.

This is an obstinate denial of sensory evidence. Moreover, on this view, no existing thing would have any essential attribute or any attribute inseparable from its essence whatsoever. Rather, every attribute ascribed to it would be accidental and could cease to exist while its reality remained. For those who maintain that substances and bodies are all alike, everything by which individual entities differ is accidental to them and forms no part of their reality.

It would then be possible for a human being, who is a rational animal, to cease being both an animal and rational while retaining his reality and essence. Likewise, a horse could cease being an animal and lose its capacity to neigh while retaining its reality and essence. The same would apply to all individual entities.

It may then be said: If we suppose these attributes, which are inseparable from the species and essential to them, to be absent, nothing remains that can be conceived as a substance, whether alike or different. For if we consider this human being and suppose that he is neither alive nor rational nor capable of laughter