I’ve had a few people ask me to clarify what I mean when I say that a statement is “incoherent.” There are three types, each increasingly sinister.

Type 1 Incoherence

`Twas brillig, and the slithy toves
Did gyre and gimble in the wabe:
All mimsy were the borogoves,
And the mome raths outgrabe.

Jackwocky, by Lewis Carroll, is a good example of one type of incoherence. The syllables in the poem can be pronounced, but they contain no meaning. The words used have no definition, so saying them doesn’t signify anything.

Type 2 Incoherence

Another type of incoherence, slightly less innocent than Type 1 because it could be accidentally confused for Type 3, is the type in which real words are used in a nonsense way. Leaves above the shelf wheel short love.

Type 3 Incoherence

This is the dangerous type of incoherence. This is the type I’m talking about, when I mention it in an essay. This is the type in which a statement is made that apparently makes sense, but that in fact contains no meaning.

Coherent: Pink Elephants

I have a pink elephant.

A pink elephant is coherent because it’s possible that an elephant could be painted or genetically modified to be pink. If I make a claim that I have a pink elephant in my possession, my claim is falsifiable, because I can let someone examine my elephant. It might exist, or it might not, but the concept is possible.

Incoherent: Unsittable Chair

I have a chair that can’t be sat on.

That statement appears to be falsifiable. We have a concept of a type of entity called “chair,” and we know the rough properties of that type of entity. We know what it means to sit on something. It seems that we can figure out whether the statement is true or not.

We can’t.

“Chair” isn’t an ontological entity; chairs don’t exist, except via our perception of how we can physically relate to certain shapes of matter (in this case, by sitting on the shape). A “chair,” then, is something we can sit on. To say that I have a chair that can’t be sat upon is incoherent because if I have an object that can’t be sat upon, then it is, by definition, not a chair at all.

But I’m not just wrong in my assertion that I have an unsittable chair: I’m neither right nor wrong. It’s neither true or false that I have a chair that can’t be sat on, because the concept precludes itself.

Incoherent is Worse than Wrong

Our mind creates a scaffold around these incoherent concepts, so they appear to have some reality to us. They feel like they could be real. In fact, the scaffold covers a fundamental non-existence. No one can say whether or not it was brillig, or whether the slithy toves gyred or not. The statement just contains no content. The feeling that it could be real is the mind projection fallacy at work.

The really dangerous thing about incoherence is that it’s hard to break the spell. You argue about something as though it exists, and you’re unable to come to any definitive conclusion about it. At least things that exist are falsifiable. Smart people fall into this trap all the time. Here’s one I bet you have heard before:

Since God can do anything, can he create a square circle?

Cute, but incoherent. Even if we accept the concept of an omnipotent God (which itself is incoherent), the definition of circle precludes that it could be a square. Untrained skeptics will pat themselves on the back for “proving” that God doesn’t exist, and untrained faithful will scramble and probably settle on God being able to do it. They are both wrong: the question simply contains no information. Can God create a mimsy borogove?