(Just a bit of fun…)
Try to think of the best thing that there could be (not just the best thing there is, by the way, but the best thing there could be). That thought makes sense, right? Let’s call that thing ‘god’, as god is meant to be the best thing that that is or could be (if he in fact is real).
So: you’ve got in your mind this best thing that there could be. Well, that’s good – but it’s not great. How great can a thing that’s just in your mind be?
If it weren’t just in your mind but in the real world with the rest of us as well, then that would be quite a plus. That would be great.
But hang on: if a god in the real world would beat the god in your mind, then the god in your mind can’t be the best thing that there could be, can it? We said at the start, though, that ‘the best thing that there could be’ makes sense. Now, for that to be so, then this best thing has to be in the real world – for real – and not just in your mind.
So this best thing – god – is in the real world. For real.
No, no, no, you’ve got it all wrong. You’ve mixed up things and thoughts.
When you think of the best thing that there could be, you don’t then have that thing in your mind. A phrase like that is just the way we tend to talk. What you do have in your mind in this case is the thought of the best thing that there could be.
(And, in fact, as your mind is in the real world with the rest of us, so your thought of this best thing is in the real world too.)
And what’s true of a thing need not be true of the thought of that thing. An ant is small and a whale is big, right? So is the thought of an ant small and the thought of a whale big? Of course not: thoughts don’t have size as things do.
Now, you’ve got the thought of the best thing that there could be (god, let’s say) in your mind. How great does that thought have to be? Great, I mean, in the way that god is meant to be. Of course, the thought is just a thought – it’s fine as it is, but it need not be great in the way that god is meant to be great (or big in the way that a whale is big, and so on).
Sure, if you think of god then you can think of him both as real and as the best thing that there could be. What’s more, you can think of him as the best thing that there is, for real. And, as far as your thoughts go, that’s fine. But this does not mean that we can put your thought of him (which is real) on a par with him (who is just thought of as real) and say that what would be true of god is in fact true of your thought of god.
There’s a phrase that goes (more or less): ‘if a wish were a horse, then a poor man could take a ride’. But a wish is not a horse. And a thought is not a god.
(I was moved to produce this during a discussion over at Alex’s. For a more thorough look at ontological arguments, see here; for an entertaining musical treatment, see here – thanks to Timmo.)