This song is Diamond N’s version of Descartes Cogito Ergo Sum. In Descartes version he proves that even if he doubts all of the world, there is still something which is doing the doubting, the unshakable belief that he is a thinking thing. From this he (ropily) derives the existence of the Universe, a benevolent god and an evil genius probably played by Alan Rickman if it is a good movie or Sting if it is a bad one.

Neil’s method is a little bit trickier. He manages to prove that chairs cannot hear early on inthis stanza:
I am, I said
To no one there
And no one heard at all
Not even the chair

From this standpoint he then moves on to the delusional aspect of the workings of someone who may want to trick us. He uses a complex example, but unlike Descartes, he then identifies with the example and suggests that this is the actual case:
Did you ever read about a frog who dreamed of being a king
And then became one
Well, except for the names and a few other changes
If you talk about me, the story’s the same one

The flaw in this is that the changes Neil is remarking upon here are actually quite significant ones. Despite his lousy croaking voice, he was never ACTUALLLY a frog and now he is not ACTUALLY a king. However what Neil does do in this song is prove definitively that there is no single self deluding person. Because if there were, why on earth would they invent someone as ridiculous as him, writing songs quite this silly?

You Are – you said. You just did not say what you are. I think I can help on that front.