What Are the Units of Selection?

In this process of natural selection, what are we selecting for? What are the units of selection? That's a great question. I think we've done far too much reverse engineering of the answer to that question from the facts of biology as we find them here on Earth which has a lot of biases built into it. A really good theory of selection and the biology that results from it ought not be so limited that it only applies here on Earth. It ought to be pretty good anywhere that process is unfolding in the universe.