The overwhelming majority of atheists have no idea where to find the best arguments for God’s existence. The same can be said of many theists as well, which may be part of the problem.
Many atheists, when they want to argue against the Christian God’s existence, set about attacking the Bible, as though Christian Scripture had a list of proofs for theism that atheists could refute. The Bible is a great book, and justly important to Christians, but if you go searching through the Christian Scriptures for a list of the great philosophical proofs of God, you’ll surely be disappointed.
The best arguments for God’s existence also have little relation to the theistic arguments familiar to students of philosophy in our day. Today, a beginning philosophy student will learn about the cosmological, ontological, and teleological arguments for God’s existence and perhaps some sort of argument on the basis of human morality. And however many years of post-secondary philosophy students may take today, the majority will never move beyond this limited approach, although they may at some point study the question of God’s existence in more detail. These aren’t bad arguments, though they’re often badly presented. My point, however, is that they are not the best.
Below, I recommend five books, all available in good and inexpensive English translations, which will introduce the contemporary reader to what is in my view the most convincing proof of God ever formulated, an argument that is furthermore (as Neoplatonists have claimed) the necessary basis of all philosophy, of all thought. It is a difficult proof, which is why I recommend five books in order to make sure the argument is adequately explained. But it is a powerful proof.
Read these five books in their entirety. Read all five, carefully, repeatedly, for understanding. It’s difficult, boring, exhausting work, but you should do it anyway, because these might be some of the most important books you’ll ever encounter. Read them all, read them in order, and don’t skip any of them. Each writer on the list would want his readers to be as familiar as possible with the works and arguments of the writers preceding him.
Plato’s Parmenides: This is the book where it all starts. It is very short, but very difficult. I remember the professor who taught me this book relating how he had seen students reduced to tears before this book in the past. Read slowly, reread, and don’t be disappointed if it doesn’t make sense quite yet. The reason for having four more books on the list is that there’s a lot to mine from this text, and most of us won’t be able to extract and understand those insights without a bit of help.
Plotinus’s Enneads: Here is the soul and center of the argument. It’s the longest book on the list, but it is also the most important. If you have to choose just one of these books to read—and I don’t recommend doing so—choose this one. Read the whole thing. It will be a big challenge, especially for those not familiar with Aristotelian terminology, but if you can grasp it, you’ll have grasped the basic argument for the existence of God.
Dionysius the Areopagite’s Divine Names: (Pseudo-)Dionysius may help you understand the Platonic argument more clearly, but also, he’ll help bridge the gap from the terminology and tradition of the monotheistic pagan Platonists, to the terminology and tradition of the monotheistic Christian Platonists, a gap all too difficult to traverse for most of us on our first engagement with Platonic literature.
Aquinas on the simplicity of God (Summa Theologica, First Part, Q3): Aquinas explicates a further (important) step in the argument, and he shows how the entity discussed by the Platonists can be identified with the God of the Abrahamic tradition.
Ficino’s Platonic Theology Books 1–3: The first three books of Ficino’s Platonic Theology will step back and survey much of the ground covered by the foregoing authors. If you must skip one of these five books—and I don’t recommend doing so—this is the one to ignore, especially since it will be the most expensive to purchase, at about $35 for the Harvard University Press translation. It will, however, be very helpful in cementing the argument picked up in the preceding books.
An atheist, after studying these books, probably won’t become a Christian. I admit it. But no intelligent atheist who gives these books a fair read can fail to become a theist.
Few atheists who read this article will act on the recommendations here offered, I’ll wager. But I hope that, in rejecting the reading list, there will appear a small seed of doubt in their thoughts—doubt of that mastery they supposed they’d already acquired of all the important theistic proofs, and doubt concerning the real reason why they first became, and more so why they still remain, atheists and agnostics.