The Ontological Argument in Plain English

The ontological argument attempts to make the statement "There is no God", or more accurately, "God is imaginary", logically incoherent. Rather than look at it in a syllogistic form, let's take a peak at it in colloquial English.

The word "God" here means the Creator of everything that exists, and by extension the greatest conceivable being. Great means "more unusual or considerable in degree, intensity, scope, etc".

So start with the statement:

• God is just in your mind (i.e., he has no extramental existence; he is imaginary)

 Let's replace the word "God" with what it means:

• [The greatest conceivable being] is just in your mind

But if something exists just in your mind, then there is a version of that thing that is greater, i.e., more unusual or considerable in degree, intensity, scope, etc. Namely, one that exists in reality as well.

Consider an imaginary vs a real elephant. Which one is more unusual or considerable in degree, intensity, scope, etc? The real one exists in your mind as well (when you think about it), but it also exists out there in reality. So it has what the first one has plus more. So existence in reality + mind is more unusual or considerable in degree, intensity, and scope than existence in just the mind.

So let's compare two greatest conceivable beings:

• [The greatest conceivable being] is just in your mind

• [The greatest conceivable being] is in your mind and also reality

The second one is more unusual or considerable in degree, intensity, and scope than the first. So the first one is not the greatest conceivable being. So the sentence "God is imaginary" really means:

• [The greatest conceivable being] is [not the greatest conceivable being]

This is clearly a logical contradiction. Something cannot be both P and not-P. So the statement:

• God is imaginary

...is logically incoherent. Which means that it's negation is necessarily true:

• It is not the case that God is imaginary

Or, to put it another way:

• God exists

Or so goes the argument. I leave it for readers to decide on their own whether this is a good argument or not. :)