Allen Buchanan, Our Moral Fate: Evolution and the Escape from Tribalism (2020)

This is an amazingly stimulating book - speculative, to be sure, as the author admits, but fascinating and, in my eyes, fairly persuasive. Buchanan starts with an important and largely overlooked puzzle: how to explain what he calls two Great Expansions in human moral sensibilities in at least parts of the world in the last three centuries. First, some people overcame the default stance of moral tribalism - only "we" are fully human and hence deserving of the highest moral standing - and began to think and act as if all humans qua humans deserved that standing. Second, some people extended the idea of rights to include some non-human animals. Buchanan acknowlegdes that some other scholars have tried to explain the First Great Expansion, but he makes the case that their answers are not persuasive, and suggests that nobody has even tried to explain the Second Great Expansion. Buchanan's puzzle seems like a genuine and quite important one. Buchanan argues that these Great Expansions are incompatible with two dogmas among the evolutionary thinkers he otherwise draws on: the dogma of tribalism, i.e. humans are naturally and ineluctably tribalistic; and the dogma of cooperation, i.e. morality is only a matter of facilitating cooperation. A key idea for Buchanan is that human morality is shaped both by our genetic inheritance but also by our social environment. Furthermore, we are niche constructors - at least partly, we make the world to which our moralities respond. Our moralities are "adaptively plastic" - in environments where tribalism is the safer bet, we will be tribalistic. But when the social environment changes - when we create safer and richer niches, for example - our morality has the room to change and become less or non-tribalistic. For Buchanan's purposes, the historical rise of the state and of markets created the conditions in which non-tribalistic moralities became possible. However, on Buchanan's account, this new niche only opened the door to the Two Great Expansions. Something more was required for people to walk through the door. Here's where he emphasizes the importance of moral consistency reasoning and moral identity. The former meant that people might expand the circle of their moral regard, first to all other people, and then to some animals. The central importance of moral identity - a term new to me, and seemingly quite promising - is in motivating people to become morally consistent. Toward the end of the book, Buchanan suggests how ideology can short-circuit the expansive power of moral consistency reasoning and moral identity and instead shore up the defenses of resurgent tribalism - as we are seeing now.