What's the Difference? On the Metaphysics of Participation in a Christian Context

The metaphysical notion of participation expresses the ontological dependence of things in the world on spiritual/intellectual realities, and ultimately on God. While the notion brings clearly to light God's presence in things, it tends, for the same reason, either to collapse into pantheism or, what amounts to the same, to deprive the world of any substantial reality of its own. This essay evaluates the place of this notion in Christian thought by exploring the question of difference in the structure of participation as it is found in Plato, Plotinus, and Aquinas.