It may look simplistic, but it took me many years to state this clearly.

Tobler's Metric of Civilization:

"We are civilized to the degree that we do something "for," rather than "to," other peoples' children."

House, feed, heal, clothe, educate, motivate, encourage, entertain, and otherwise promote the happiness of other peoples' children and you are civilized.

I leave the "to" part to your imagination.

By the way, the measure also seems to work equally well at the other end of the spectrum, so we have --

Tobler's Alternate Metric of Civilization:

"We are civilized to the degree that we do something "for," rather than "to," other peoples' old folks."

To understand my meaning of "old folks," think of your most beloved grand parents, aunts, and uncles.