This summary on Christian metaphysics and Idealism is from the Introduction to Four Views on Christian Metaphysics.
Idealism is very distinct from both Platonism and Aristotelianism in that it is (like materialism) distinctively not dualistic. Idealism is a form of monism. There is only one kind of substance, not two. While there are a variety of “idealisms” in the history of metaphysics, the most prominent form was defended by George Berkeley. Berkeleyan idealism maintains that all of physical reality is a collection of ideas, and what we take to be different types of physical bodies (books, chairs, shoes, etc. ) are really all ideas. Idealism maintains a very strong role for God in Christian metaphysics, since it is claimed that “to be is to be perceived.” That is, everything that is real is real because of God’s perception of it. Idealism of this form will give an account of how all of reality is ideal in nature and how it is dependent upon the mind of God.
I recommend obtaining a copy of the book and reading Chapter 3. The outline for the chapter is as follows:
3.1 Idealism – James S. Spiegel
3.2 Platonism Response – Paul M. Gould
3.3 Aristotelianism Response – Timothy L. Jacobs
3.4 Postmodernism Response – Sam Welbaum
3.5 Idealism Reply – James. S. Spiegel
~ Boethius ~