Argument

The term “universal” is ambiguous; it can indicate either what actually exists in several instances, or what can so exist, even if it is actually exemplified in only one instance. The former sense implies the latter, but not vice versa. It is suggested that form for Aristotle is universal in the latter sense, including what is part of the nature of a species but not individual accidents due to the matter, and that this may help to explain a problematic passage in Metaphysics Z 15. Analysis of passages in Metaphysics Z 8 may however suggest that form as universal in the former sense exists only as a potentiality. The claim that form includes only specific, not individual features has implications for Aristotle's theory of heredity; more generally, his theory of form reflects the tensions between Platonist and non-Platonist elements in his thought and his methods of enquiry.