Substance and what it means to be › What the Argument Still Asks of Us

A serious objection concerns the move from explanation to an unmoved source. Why must a sufficient explanation have the specific form Aristotle demands? Even someone who grants that particular changes have causes can question the premises about eternal circular motion or the adequacy of final causation for explaining it. Within XII, those premises carry argumentative weight; repeating the conclusion cannot establish them independently.

Another difficulty concerns unity. If matter and form are distinguished, why do they constitute one thing rather than two? In VIII.6, Aristotle responds by treating the relevant matter as potentially what the form is actually. The distinction is not between two independently completed objects requiring a third object to join them. The critic can still ask whether this explains unity or redescribes it. That is a substantive disagreement about what an adequate explanation must provide.

These questions suggest a useful way to read the book now. When investigating a difficult case, separate a list of materials from an account of organization, an available power from its exercise, and a purpose from a source of physical change. Then ask which distinctions help with the particular case and which assumptions remain unproved. No immediate conclusion about machine consciousness, corporate personhood, or personal identity follows simply from using the vocabulary. Those applications would require additional arguments about what the relevant things are.

The house in the yard offers a starting discipline. Before claiming to understand something, ask whether you have named its components, described a property, identified a capacity, or explained why it is the definite thing it is. Aristotle's investigation asks us to distinguish those achievements. Its difficulty is productive when it makes an explanation more exact, rather than furnishing a grand name for what remains unexplained.