This one's easy -- unlike function one, which is a little woo-woo-spiritual, function 2 is simply to present a functioning model of the natural world. The Earth is at the center of so-and-so, or all matter is comprised of four elements, or prehistoric souls were blown up in volcanoes -- it's whatever sciencey machinery feels right.

"Feels right" is the crucial part here -- it doesn't need to be correct, just gratifying.

Alas, our myths haven't kept pace with our science; and while the old models feel very nice -- God is a magic spaceman who lives in the clouds and loves you! -- it's harder to suspend your disbelief than it was in the old days. Something new will probably come along eventually; but until then, there's a lot of speculative mythology jostling for attention.

"Explain" is the primary goal with Function Two -- "here's how the universe works, and with this knowledge you will understand all with which you may come into contact."