"Shema Yisrael Adonai Eloheinu Adonai Echad."
"Listen, Oh Jews, Hashem is our God, Hashem is One."
At which point he laughed, and said:
"But Hashem is not one! Hashem is an infinite number of years old."
Then he thought for a moment or two, and proceeded seriously.
"And that means that no one could have created Hashem."
"Why?" (I asked.)
"Because Hashem is also infinitely big. And so if someone were creating Hashem, he would still be working on it! So no one could have created Hashem." (That is, it would take infinite time to create something which took up infinite space.)
He came up with all of this, unprompted. This, BTW, is a good answer to the objection that I should not be teaching the idea of a non-concrete shamayim to a kid under five, because it would only confuse him. This is probably a valid objection for many five-year olds. And Junior does indeed have a need for an idea of a concrete and physical Shamayim because of various people he cares about who are there. But still, chanoch lanaar al pi darko, and if a particular kid can handle it, I think it is justified. (Also, he actually argued with me and gave me an alternative theory to this idea of a non-concrete shamayim, but perhaps detailing that in a separate post.)