Substance and what it means to be › What Could Substance Be?

Book VII.1 renews the inquiry by connecting the question of being to the question of substance. Aristotle presents substance as prior to the other categories in definition, knowledge, and time. He explains the temporal priority through substance’s independent existence, since the other categories cannot exist on their own. This does not mean that a thing first exists without any properties and only later acquires them. His motivating contrast is between what a thing is and such descriptions as its quality or quantity. Knowing that something is pale does not yet tell us what the pale thing is. The basic explanatory subject remains to be identified.

In VII.3 he lists essence, universal, genus, and underlying subject among the candidates for substance. Within the discussion of the underlying subject, he distinguishes matter, form, and their compound. The bronze, the form of a statue, and the concrete statue exemplify those distinctions. These are candidates examined within an inquiry; they are not three interchangeable labels with no further questions attached.

Matter has an obvious attraction: it seems to underlie the changes in a thing's characteristics. But imagine stripping away every determination, including quantity and shape, to isolate a wholly indeterminate underlying subject. Aristotle objects that this result does not satisfy the separability and determinacy associated with substance. An answer that leaves us unable to say what anything is has failed to explain precisely what the investigation seeks.

That argument gives form a claim to explanatory priority. It does not mean that ordinary living things cease to be substances, or that only a detachable abstract form is real. Aristotle explicitly includes the compound of matter and form in the discussion. The interpretive task is to distinguish the concrete thing from what explains its being the definite thing it is. Treating the text as a simple elimination contest, in which matter and compound disappear entirely, obscures that task.

VII.13 introduces a further constraint by arguing against the universal as substance. Aristotle reasons that substance belongs peculiarly to the individual thing, whereas a universal is common to several things. This complicates any easy equation of form with a general property shared by many individuals. A reader has to ask how an explanatory account can apply to many things without itself becoming another independently existing thing alongside them. The book makes this problem visible; a short introduction should not pretend to resolve every tension it generates.