The Flaw in the Ontological Argument

Imagine the most awesome thing ever. The most awesome thing ever would be less awesome if it didn't exist, right? Therefore, it must exist!

That's the ontological argument, an attempt at an a priori argument for the existence of god. A god. Some god. Any god. Something?

That's the final panel from a comic at MacHall. Click through for the full thing. It points out the most serious error in the ontological argument.

The ontological argument is at least a thousand years old, being first clearly stated by St. Anselm. It may have been implicit in older writings that made it down to us, though, but Anselm gets credit for being the oldest we have who spells it out. The argument is literally as follows:

• Our understanding of God is a being than which no greater can be conceived.
• The idea of God exists in the mind.
• A being which exists both in the mind and in reality is greater than a being that exists only in the mind.
• If God only exists in the mind, then we can conceive of a greater being—that which exists in reality.
• We cannot be imagining something that is greater than God.
• Therefore, God exists.

It can be easier to know that the ontological argument is flawed than to point out where the flaw lies. Not least, I think there are several flaws. However, I feel the greatest flaw can be elucidated with this counter-argument: Only in your wildest dreams do you imagine that your dreams can become reality. In other words, through logic, reasoning, and clever definition, do you honestly believe you can will god into existence? When speaking of a possibly extant being in our actual factual reality, you must necessarily base your argument on that reality. Mere supposition can never take precedence over verifiable¹ observation.

Logic and philosophy can, in fact, guide you in your search for an extant being, even in the absence of any new observation or facts. However, it does so in the negative sense, by demonstrating that an idea or concept is incoherent, or paradoxical, or impossible. I can conceive of an object that is perfectly red (once redness is adequately defined). I can conceive of an object that is perfectly blue. I can conceive of an object that is simultaneously perfectly blue and perfectly red... but the concept is incoherent and such an object could not possibly exist. I can conceive of an object half of which is perfectly blue and half of which is perfectly red, and so long as those two halves don't overlap, the incoherence is gone. Some have argued that the very concept of god is incoherent, and I'm inclined to agree and extend that incoherence to the concept of the supernatural as a whole, but that discussion is still on-going and unlikely to be resolved.


There's nothing impossible about a unicorn. It's just a horse with a horn. Rhinocerontes, narwhals, elk and deer; there are a lot of different ways to get pointy crap to grow out your head. It's not beyond conception that an eohippus might have experimented with a keratinaceous nodule or some sort of toothy accouterments.

Consider the Pegasus. A horse with wings? Easy! Just take a horse and add wings! Except, of course, that no mammal ever has been hexapodal. In fact, all mammals, reptiles, birds... tetrapodal. Adding another pair of limbs would a massive development! Forelimbs are distinct from hindlimbs, and midlimbs would require brand new skeletal and muscular developments, changes to the development of the entire organism down to the embryological level. And then those limbs would have to evolve into wings! And even if said hexapodal monodactyl creature superficially resembled a member of the genus equus, it would not look like a horse because of the massive structural changes necessary to accommodate a pair of wings! In other words, there will never appear on this earth anything that looks like the classical conception of the Pegasus.

We know the unicorn doesn't exist not because it's impossible, but because we've looked. We've been all across this great world and there is not and, to the best of our knowledge, has never been a unicorn. We know the Pegasus does not exist because it's impossible. You can't just put wings on a horse like you can a horn.

Sometimes I think god is a unicorn. Sometimes I think god is a pegasus. Either there cannot be a god, or there simply is not one. And either way, I have the same respect for the opinion of those who think there is as I do for those who earnestly believe in the unicorn or the pegasus. None. I might have some respect for the people who hold the belief, but not the belief itself.


1 - Notice how "truth" is the core of that word.