If historical gaps highlight the potholes within our disciplinary corpus, the four other limits -- diachronic limitations, synchronic limitations, systematic closure, and structural limitations -- identify the asymptotic boundaries of that corpus: boundaries we can infinitely approach but never reach.

Examination of the unknowables, then, is not to poke about within a residual, trash-can category. Rather, to grasp the unknowables and why they are truly unknowable is to come to new insight about the nature of men and women. And that is anthropology at its most fundamental.