I understand Platonism to be a field of study. Platonism studies metaphysical objects like causes, numbers, purpose, evenness, oddness, angels, mind, justice, love, and so on. Now, I recognize that I am being reductive here. Plato and platonists have spoken about a great deal many things. But I find this basic and simple definition helpful because it names what Platonism is in a way accessible to most today.
A brain surgeon studies the technique of brain surgery. A biologist studies biology. A platonist studies intellectual objects like love and numbers. It is easy to see why Christians might adopt platonic concepts. Theology—the study of the invisible, unseen God and his works—speaks about a divine Being whose existence lies outside of regular sense experience (sight, smell, etc.). An angel, heaven, a demon, a power, a throne, and more besides generally are understood to exist in a way that differs from a dog, person, or house.
Christian Platonism, in my view, uses appropriate language to talk about intellectual (i.e. non-material objects). Christianity adopted that language to organize their thinking around God and his works. Particularly, to conceive of one God who Paul calls “invisible” (1 Tim 1:17) or to conceive of how the invisible Logos becomes flesh (John 1:14) takes careful thinking. Platonism or philosophical language in general provides the tools for the job, just as physics can describe how the world works.
Alexander J. B. Hampton and John Peter Kenney appear to say something somewhat similar in their introduction to Christian Platonism: A History when they say, “At various times, Platonigms has constituted an essential philosophical and theological resource, furnishing Christianity with a fundamental intellectual framework that has played a key role in its early development, and in subsequent periods of renewal” (3). [Read more…] about Christian Platonism: A History (a review)