okay sure, maybe “debunking” is harsh, but I don’t think what you are looking for is possible given Selgin’s whole point is that you just can’t know this stuff. Graeber conflates an absence of evidence with an evidence of absence and Selgin says, “okay, not only is that silly, but if you think about what you are analysing, of course there is an absence of evidence. how could there fail to be?”
Discussion
I agree with that argument, but that is not quite true either. He provides anthropological evidence that barter->coinage->credit it is not the only direction in which money evolved, not just in simple societies but also in complex and large early civilisations.
That of course does not mean that the barter could not have been a proto economy in some parts of the world, but it also shows that the reality is much more interesting and complex, and that people are highly creative. So I highly recommend Graeber for his anarchistic creativity, even though I accept that his fews are limited by his ideology, which is the case for anymof us. I mean Selgin also does not see Bitcoin as money, so he is far from perfect: )