First, I take no credit for this joke, which many of us heard at the Peterborough diocesan conference this year.

Second, in order to tell it to my family at tea the other evening, I had to explain something about what Rene Descartes was renowned for. Not an easy undertaking  given that I’m not exactly an expert in philosophy. He is famous for the phrase “I think, therefore I am” (cogito ergo sum). It is to do with asking how do I really know anything actually exists, how can I tell that I am not deceived, making it all up, dreaming or whatever. The conclusion he reaches is that even if everything that exists is all in the mind it must mean that he exists because he has to exist in order to be able to dream/think it.

Descartes walks into the bar and orders a drink. When he finishes he thanks the barman and turns to go. The barman calls after him, “Sir, would you like another drink?”

“No, thank you,” replies Descartes, and turns to go. “I think you really would like another drink,” insists the barman.

“I think not,” said Descartes and disappeared.

At the end of the telling of this joke one response I got was: “That’s very funny!” but it turned out that she had stopped listening and was looking at her reflection on the inside of a spoon.