Darwin opened his “M” notebook in the summer of 1838, when he had already formulated the thesis of common descent but not yet the mechanism of natural selection. The “M” notebook was dedicated to “metaphysical” considerations (note well: the modern usage of “metaphysical” differs). Speaking very broadly, it explored the evolutionary history of human psychological traits. On page 128, we find Darwin’s at his most quotable:
Plato says in Phaedo that our “necessary ideas” arise from the preexistence of the soul, are not derivable from experience — read monkeys for preexistence.
Ever since Darwin it has been evident that much of our emotional and cognitive furniture must be explained by our evolutionary history. This is one of the most philosophically significant aspects of evolutionary biology, but also one of the hardest to explore empirically.
Frans de Waal’s Primates and Philosophers: How Morality Evolved is a modern continuation of Darwin’s “M” project: a reflection by a leading primate researcher on the evolutionary origins of our moral sentiments. It is tremendously enjoyable. I can give it no higher recommendation than to note that I have already ordered more books by the author. De Waal argues that the “building blocks” of human morality can be found in our primate relatives and are the results of evolutionary processes such as reciprocal altruism, kin selection and perhaps (de Waal is skeptical) group selection. This is of course not unique: The value of the book lies in its copious and lucidly presented empirical material on the morally significant behavior of primates. De Waal argues forcefully and intelligently that moral behavior is not a thin “veneer” of good behavior plastered onto a brutish, selfish psychological core. Instead, acting morally is as human (or primately) as anything.
The book also includes comments by a number of philosophers. These are not as engaging as the science (although this may reflect only my interests), but they are useful. I particularly liked Philip Kitcher’s contribution. He argues that the “veneer theory” of human morality, which de Waal attacks at length, may be a straw man: Who really believes that morality is a purely cultural layer on top of a selfish underlying biology? I suspect that de Waal needed some sort of dialectic to get going with his argument, but “veneer theory” may not be a good choice, and I rather doubt that he is being fair to those he names as exponents of the view (such as Thomas Henry Huxley and Richard Dawkins). A more productive sparring partner might be one of the following positions: (1) The assumption (which may be prevalent among philosophers) that morality is a matter of reason and not of evolved emotions; or (2) the charge that de Waal’s primate research is merely “descriptive” and so has no bearing on morality, which is understood to be “normative”.
As a separate point, Kitcher argues that it is insufficient to speak of the foundation of morality in “altruism”: different dimensions of altruism must be distinguished in order for the “building blocks” notion to be made precise. I think this is a useful conceptual clarification. It lays groundwork for the continuation of the exciting and difficult empirical project.
The elephant in the room does not get much discussion, perhaps wisely: It is the conclusion (which I find nearly inescapable, and de Waal might agree) that an understanding of our moral sentiments is all there is, or almost all there is, to understanding the foundations of ethics and morality. For now, I leave it to Hume and Ruse and Wilson to argue for this – but read also Peter Singer’s contribution to the book in hand.