Benjamin H. Arbour Two Cheers for Idealism! In contemporary debates about fundamental ontology, Berekeley’s idealistic immaterialism has not received the attention it deserves. In this paper, I argue that idealism is required by non-platonist understandings of Christian orthodoxy. I show that the combination of Nicene understandings of the doctrine of creatio ex nihilo and the doctrine of divine conservationism entail some sort of idealism. I explain that even minimalist accounts of divine conservationism are enough to generate idealism. That is, whether divine providence is entirely passive (deism), or completely active (occasionalism) or something in between (e.g., process theology, open theism, Wesleyan/Arminianism, or Calvinism), idealism follows, so long as we take God to be an omnipotent, immaterial, rational being who is responsible for the creation of all things, seen and unseen. I explain that although Nicene orthodoxy entails idealism, this idealism can be interpreted in two ways: one that admits of substance dualism (or pluralism), which I call Thomistic idealism, owing to Aquinas’s understanding of divine ideas/exemplars; and Berkeleyan immaterialism. I show how neo-Aristotelian conceptions of matter yield Thomistic interpretations of idealism, whereas the innovations offered by Rene Descartes and John Locke with their definition of matter as “that which exists independently of mind” yield Berkeleyan immaterialism. I conclude by showing that idealism offers several benefits to Christian theologians, whether construed along Thomistic lines or Berkeleyan lines. The two areas that I touch on deal with models of philosophical/theological anthropology and God’s relation to time.1 1Some material from the last section comes from two forthcoming pieces: Benjamin H. Arbour, “Two Cheers for Idealism,” in The Ashgate Research Companion to Theological Anthropology, eds. Joshua Farris and Charles Taliaferro (Burlington, VT: Ashgate, 2014), forthcoming; and idem., “A Berkeleyan Approach to God and Time,” in Idealism and Christian Philosophy, eds. Jim Spiegel and Steve Cowan (New York, NY: Bloomsbury, 2015), forthcoming. .