This is a story. We need to construct a narrative that carries our themes with enough mysteries explained and enough problems considered that it has the ring of truth. It isn't desirable or even possible to mention all established evolutionary explanations or all our speculations, and it isn't necessary or even desirable to explicitly consider all problems and objections.

The emphasis should be on mysteries that are likely to be familiar (so don't require too much background) and on problems and objections that are “common sense” or are more prominent. However, an important theme is that social and psychological facts need evolutionary explanations, and to motivate this, it is necessary to give the background that will build a sense of mystery.