A Natural History of Human Morality by Michael Tomasello (review)

The dust jacket to A Natural History of Human Morality advertises “the most detailed account to date of the evolution of human moral psychology.” Reading this description, you might expect a hefty, multi-volume work filled with mitochondrial maps, genotype to fitness landscapes, and appendix after appendix of experimental results. Thankfully, you will find none of these things within this slim, breezy, 163-page monograph. What you will find could be better described as an “introduction” or an “outline” to an ongoing research program, which may very well become the “the most detailed account…of the evolution of human moral psychology” that we can hope for. But the greatest virtue of A Natural History of Human Morality, to my mind, is its merciful lack of detail. Tucked between its narrow covers is a simple yet engaging story about the emergence of a new kind of cooperation among upright apes, which we call “morality.”

With its welcomed brevity and immanent readability, this book can be enjoyed by just about anyone. However, it will probably appeal most to readers who have neither the time nor the background to keep up with the many articles that Michael Tomasello publishes every year, but who want to find out what all the hubbub is about. If you’ve never read a book on the evolution of morality before, there’s no better place to begin. For those of you who have kept up with Tomasello’s work over the years, you’ll find little that you don’t already know, but you will walk away with a clearer understanding of what he’s up to and where his project is headed.

What is the book about? In Tomasello’s own words, the “goal of the current account is to provide an explanation, an evolutionary explanation, for how the human species transformed great ape strategic cooperation into genuine human morality” (147). More specifically, Tomasello identifies a number of moral psychological capacities that are unique to humans, and then defends an empirical hypothesis about how and why these capacities evolved in our genus (and only in our genus). [End Page e-10]

The story begins with the great apes, or, more precisely, with the most recent common ancestors of humans and great apes. These apes, like their non-human descendants, were built for competition. They exhibited a kind of “Machiavellian intelligence,” implementing flexible strategies and even predicting the mental states of conspecifics, if for no other reason than to outsmart them (22). However, these early apes were also able to form long-term partnerships, since the scales of competition could be tipped in one’s favor by enlisting the help of some close friends, whether for a fight or a monkey hunt. Thus, we find in these ancestral apes a number of proto-moral psychological capacities, organized around feelings of sympathy toward kin and collaboration partners. They could be moved by the plight of others, and could even inhibit self-interested impulses for the sake of maintaining social cohesion. According to Tomasello, these apes and all their descendants, including humans, are capable of a primitive “Morality of Sympathy,” defined by the aforementioned moral psychological capacities.

Fast forward five million years or so to early humans. These hominids still followed the Morality of Sympathy, but they had acquired new moral psychological capacities, which enabled them to follow the more complex “Morality of Fairness.” Collaboration had become more common, and to collaborate more easily and effectively, early humans developed the capacities to engage in joint attention and to form joint commitments (76). They placed an intrinsic value on working together with others, and so were less likely to renege on partnerships, even if reneging would bring greater rewards. Furthermore, they developed an abstract conception of what a collaboration partner ought to be and do, leading them to select partners carefully, to reward good partners, and to punish bad partners through expressions of second-personal agency. Whereas great apes allow collaboration partners to enjoy small portions of a food prize, but keep the lion’s...