He's been learning about god and Jesus at school, it's that time of year. It seems he's skeptical.
"If god made everything" he said, out of the blue "then what made god?".
It is the classic refutation to the first cause argument for god's existence. I didn't have an answer (nobody does) so I said that I'm sure his teachers would enjoy explaining it all to him and he should ask them, when the donkey and stable business comes up again.
Problem with this first cause thing is that it applied to physics too. Big bangs out of nowhere makes as little sense as sudden men in clouds.
The other arguments
The other arguments that philosophy of religion students are taught are the problem of evil and the watch maker. Here they are.
If god is all powerful, all knowing and good; then why is there evil? If he's not some of those things then he's not much of a god.
It takes a very clever man to make a watch. People are much more complicated than watches, in fact it's amazing that we can see, think and do whatever complex organs do. So whatever made people, walruses and onions must be pretty much god.
The best refutation of this I read is from Richard Dawkins who points out that this is like saying a puddle is really smart for fitting exactly in the hole. We are complicated because we've adapted to survive. If we were rubbish we wouldn't be here, like the puddles that aren't.
Innate skepticism then; healthy, human.
