Abstract
The limitation of act by potency, central in the metaphysics of Thom
as Aquinas, has its origins in
Plotinus. He transforms Aristotle
’s horizontal causality of change
into a vertical causality of
participation. Potency and infinity are not just un
intelligible lack of limit, but productive power.
Form determines matter but is limited by recepti
on into matter. The experience of unity begins
with sensible things, which always have parts, so
what is really one is
incorporeal, without
division and separation. Unity is like the esse of
Thomas, since it is the act that makes a thing
what it is and has its fullness in God.