I have given many lessons on proofs for the existence of G-d. (#HumbleBrag) I love Aquinas’ Five Ways. I love Augustine’s argument from Truth. I’m intrigued by arguments from miracles and from desire. I’ve taught all of these and when I do I usually preface the discussion with a warning. Something to the effect of, “There is no single proof I can offer that will definitively prove G-d’s existence.” (“Proof” is a funny word.) When I talk about proofs for the existence of G-d my goal is at least to show that atheism is challengeable and at best can be shown to be illogical. From there, with all of the “proofs” or arguments considered together, a person can begin to see the puzzle come together and begin to see why it must be true that G-d exists.

I say all of that, but I honestly don’t exactly believe it. There is one argument that kind of does work absolutely and on its own. I usually don’t bother with it because it is utter lunacy to most audiences. Yet, for hundreds of years, no philosopher has been able to prove the argument wrong. I speak, of course, of the ontological argument.

Why is the ontological argument so powerful? Or, A Brief Lesson in Logic.

“Logic” as a concept is pretty simple to grasp. Philosophers however, can never leave well enough alone, so there exists a complex system in philosophy for expressing and working thoughts logically. For our purposes, let’s call this branch of philosophy “Formal Logic.” Formal Logic is perhaps the foundation of philosophy, so it’s worth learning a little about it. (If you only take on philosophy course in school, make it an Introductory Logic class. You won’t regret it!)

In formal logic an argument is typically laid out as a syllogism. In a syllogism the premises of an argument are listed first, followed by the conclusion of the argument. One famous example of this form is given below.

1) All men are mortal.

2) Socrates is a man.

3) Therefore, Socrates is mortal.

As you can see, there are two premises offered which lead to a conclusion. The form is valid, meaning the premises lead to the conclusion, and the argument is considered sound because all of the premises are true.

It is possible to have a valid argument which is not sound. For example:

1) All men are bananas

2) All bananas are dumb

3) Therefore, all men are dumb.

If the premises were true, they would lead to the conclusion, making this argument valid. However, the premises are not true and the argument is not sound. Even if the conclusion is true regardless. (Sick burn, men!)

That’s basically syllogistic logic. The ontological argument has endured as long as it has because, abstract as it may seem, the argument is valid and sound. Try to keep that in mind going forward.

The Argument

The Ontological Argument comes to us from Anselm of Canterbury’s Proslogion. The argument is called “ontological” because it starts with an examination of G-d’s “being” and its nature. (Ontology is the branch of philosophy that deals with being and meaning. Basically.) This is the reverse of how we typically come to understand a thing. Typically we encounter an object (meaning the “object” of our study) first and we discover its nature and its meaning by studying the object. In Anselm’s argument, we begin with a discussion of the nature of the “object”, in this case “G-d,” and through that discussion arrive at the object itself.

I could be annoying and give you a lengthy formulation of the argument from the Proslogion itself, but this blog isn’t about trying to sound smart. Instead, I’ll give you a much cleaner presentation of the argument which I am pulling directly from The Handbook of Catholic Apologetics. (If you don’t own this book, what is wrong with you? Do you even want to go to Heaven, dude?) If you want to read Anselm’s version, you can do so by scrolling to chapter two here.

Here is the argument:

1) It is greater for a thing to exist in the mind and in reality than in the mind alone.

2) “G-d” means, “that than which a greater cannot be thought.”

3) Suppose that G-d exists in the mind but not in reality.

4) Then a greater than G-d could be thought. (Namely, a being that has all the qualities our thought of G-d has plus real existence.)

5) But this is impossible, for G-d is “that than which a greater cannot be thought.”

6) Therefore, G-d exists in the mind and in reality.

Go ahead. Read it again. Read it a couple of times. I’ll wait.

The argument says if we can conceive of the concept of G-d, then he must exist. Definitionally, G-d has to exist.

That sounds crazy, but logically it is perfect. Look at the structure. If true, do the premises lead to the conclusion? Yes. Take a look at each premise. Is there any premise which is untrue? No. This is a sound argument. Even if it is ridiculous.


I try to keep my posts short, but I knew when I decided to do the ontological argument that I wouldn’t be able to be concise. Instead, I’m doing this in multiple parts. For now, I’ll leave you to chew on the argument itself. Next week(?) We will look at some objections to the argument.

Until next time, Internet!