Where to Find Everything You Don't Know

Here's an exchange that took place in the car on the way to the mall:

Four-Year-Old Son (henceforth 'FYOS'): Is Arizona in the United States?

Me: Yes.

FYOS: How can it be so far away and still be in the same country?

Me: Well, the United States is a big country.

(Short pause for thought, apparently about the distance between Wisconsin and Arizona and all the people that reside in the intervening space...)

FYOS: How can God make all those people without getting tired?

Me: I don't know how. That's a very good question.

FYOS: We'll have to look that up in the dictionary when we get home. That's where you look for everything you don't know.