After considering myself a Thomist for quite a while, I have jumped ship and I now consider myself a Theistic Idealist. Below I will explain what Idealism is, and why I have adopted it as my current metaphysics. But first we can ask, “What is Metaphysics”?
Metaphysics is the branch of philosophy that asks big questions such as what kinds of things exists (do numbers exist in reality or only in our minds? Is it possible for there to be a soul? Is there only material things or are there material an non-material realities etc.). Metaphysics seeks to get down to the very bedrock of reality by asking questions about what is necessary for anything to exist at all. So those are the types of questions that Idealism or any other philosophical theory seeks to answer.
So, what is theistic idealism? Theistic idealism is the philosophical position that the only things that really exist in the world are minds and ideas. There are no material substances considered apart from some mind. So, the table I am sitting at typing is a collection of ideas like solidity, brown color, extension in space, and a position in time; all of these properties are actively given to me from the external world. In this sense I am a passive recipient of ideas (any mental image or representation in my mind). I only have access to the external world through my perceptual ideas, and when I attempt to get down to the essence of material substance I find there is nothing there. Take the example of a candle. You hold it in your hand, it has a certain feel of solidity, it has a fragrance, and it can hold the wick of a candle. Now light that wick and allow the candle to completely melt. Does the candle still exist? No, just a puddle of wax. Light the wax on fire and it beings to vaporize the liquid wax and breaks it down into its hydrocarbons, and there is nothing apparently left of the wax. All of this is filtered through our senses and perceptual experience. In this example the candle presents a question for us: What is a candle? When we answer this we will appeal to various attributes of the candle its solidity (but we can have a melted candle), its shape (a stick, but that will go away as well), having a thread up through the middle (though that will burn away). All of these individual properties will change, but what was the candle? It seems the candle is simply a bundle of our perceptions that appear to us, there isn’t any necessary material substratum underneath these properties, since in order for us to know what those material substratum are we would have to perceive them in some way (either in though or in our ideas of sense and perception). So, it is conceivable that the world is made up of ideas that are presented to us in experience, but there would be no material substratum.
The question next becomes: Whence come these ideas? Well, they come from a mind, since we know that ideas do not float freely in some realm of their own. Ideas are always the products of minds. I would add to this that necessary ideas of mathematics, geometry, and morals (if you are a moral realist) would be eternal and unchanging principles or ideas. So, on the theistic idealist schematic God’s mind is the source of these eternal unchanging principles (assuming that some form of anti realism about numbers isn’t true, but even if it is you would still need God to account fo them). So, everything that exists is a thought in God’s mind, and he communicates these ideas to our minds. The order of nature would simply be the coherent “speech” of God to his creatures.
Besides ideast he theistic idealist believes in created minds and the uncreated eternal mind of God. We could also phrase this in terms of agents. An agent being any active being. Activity being thinking, willing, and the other things that make up an agent cause. The fundamental thing that distinguishes agents from other things in our ontology is activity. Human beings are not always active, we have material (sensible) bodies and sensible things are passive. Human beings can be passvive or inactive as well, but God being the most perfect being is pure activity. He exists in all times and places, and is the foundation of time and place. As Saint Paul told the Athenians, “In him we live and move and have our being.” Here are some perceived benefits of this view for Christian Theology in my opinion:
1. On the idealists theory God isn’t far from anyone of us, and His omniscience and His Omnipresence is His presence to the contents of his own mind.
2. The second clearl advantage I can see is the issue of Creatio Ex Nihilo. It is also claimed that Creatio Ex Nihilo is incoherent, but if the Idealist thesis is true, then we have a ready made analogy between God’s mind and the mind of his creatures. When we think of any imaginary thing we create an idea, and as long as the idea is held before the mind it is in existence. When we cease to think about it, it exists no more. Hence, it is easy to see that a mind of infinite power could uphold a set of ideas up in his mind indefinitely or eternally.
3. God’s relationship to time is often viewed as a problem, but it would not be on this view, since the whole of God’s existence would envelop the created order. He would be the very foundation of the temporal order.
4. Problems with the idea of material substance would go away. Since Aristotle philosophers have puzzled over the foundational constituents of matter. What is matter at its base beneath the infinite flux of properties that are applied to it (quarks, bosons, Fermions, energy, etc). Aristotle called this stuff “Primary Matter” it didn’t really exist, or not exist. It existed in between also known as potentiality. Theistic idealism cuts the need out for this thesis. All that exists is the infinite mind of God, ideas, and created minds. It is a much simpler explanation and incorporates all the data of experience.
I end this with a quote from Berekeley: “For the Schoolmen though they acknowledge the existence of Matter, and that the whole mundane fabric is framed out of it, are nevertheless of opinion that it cannot subsist without the divine conservation, which by them is expounded to be a continual causation.”