This volume appeared originally in French in 2004 (de Sousa is an Emeritus Professor of the University of Toronto) and then in his own translation in 2007; what we have now is a handy paperback edition.

Evolution by natural selection has yielded eyes of exquisite apparent design, as well as appendices. Humans react and come to quick decisions that may not agree with the answers reflective thinking would give, we have however constructed elaborate systems of logic and mathematics that give us, at least within their own assumptions, what are the right answers. But both of these capacities have presumably been shaped by evolutionary pressures. De Sousa sets out to explore the parallels and specificities of these processes and hopes to reveal that our inheritance provides us with “a virtually unlimited range of possibilities for human flourishing” (p. vi).

Along the way de Sousa points out several important distinctions — e.g., ‘rational’ versus ‘irrational’ compared with ‘rational’ versus ‘non-rational’ (pp. 6-9), analog versus digital (pp. 12-18), ‘general’ versus ‘specific’ compared with ‘general’ versus ‘particular’ (pp. 74-75) — and comments on a host of topics in the area: detection versus representation and tropism versus desire (pp. 9-11), teleology (ch. 2), individual versus collective rationality and the units of selection (ch. 4) and modularity (ch. 5). among many others.

The reader is introduced to many of the standard issues in the common ground between  rationality and evolution. In some cases de Sousa pursues his own take on the problems, defending Dawkins’ focus on the gene rather than the organism, for instance; elsewhere he simply sets out the pertinent findings. It is an informative and amusing survey of the  issues.

Some of the major steps in the argument are not too clear. The capacity to distinguish between a general feature and a particular object that exemplifies it is “accessible only to minds capable of using the machinery of language” (p. 73) – this is also “one of the conditions that makes possible the multiplication of values” (p. 73). A little later he says “what animals and machines lack is the means to apprehend the particular as distinct from the specific” (p. 75). But then we are told (p. 83) that dogs can recognize their masters and vampire bats practice reciprocal altruism. The thought is presumably that this is done, not by identifying reference to individuals, but by highly specific general features — de Sousa notes that such animals can be fooled by an individual who makes itself indistinguishable from the trustworthy individual. But so can we all. The fact that language permits us to raise a finer-grained question does not necessarily help us that much in distinguishing Maurice from his identical twin David.

Relatedly I did not see how the fact of being able to make individual reference yielded the variety of human goals that de Sousa applauds. Of course, if A can distinguish B from C then A can have the goal of B’s welfare rather than C’s; and so the population can have any number of distinct goals; but value pluralism is surely more than that: it is that A values one kind of life for A and maybe others, while B values a different kind of life for B and maybe others. Creatures with the capacity for individual reference might not go so far: Popper’s closed society is not a logical impossibility.

At one point de Sousa seems to respond by pointing to the gap between me, the person who is able to reflect on his or her goals, and the selected-for goals of the genes I happen to embody. But he also seems to equate deciding against these primordial pressures with irrationality (p. 86), though it would seem now pretty obvious that the multiplication of homo sapiens genes is no longer in any species’ interest, unless it be that of various bacteria and viruses.

In a brief survey of so many issues it is almost inevitable that some connections will seem less than convincing. My more general worry is perhaps about the title and aim of the book than the detailed content. De Sousa’s preface mentions the view that we ought not to engage in reflective thinking but rather go with our gut feelings and says he will take this seriously. He reminds us of our fallibility in many areas of reasoning, especially when statistics or probabilities crop up. But his concern to display the ‘wisdom’ of processes that have presumably been selected for means that it is not at all clear whether in the end he is recommending a change from the status quo. As he remarks at the end of the first chapter, “our faculties’ defects are just the flip side of their virtues” (p. 18). This is, I think, a reflection of the problem labeled the ‘naturalistic fallacy’ in ethics: if what is has been selected for, it has been overall pretty successful, so how can one maintain that things should be different? More generally, if the normative is the natural, what scope is there for demanding change, for appealing to norms to promote different, ‘non-natural’ ways of doing something, leaving aside naturalistically specifiable impairments?

But let me not end on a critical note. De Sousa has provided a well-informed and argumentative survey of issues relating to how we do in fact think and how we sometimes fail to get what we have convinced ourselves are the right answers. His brief concluding remarks about the functions of emotions are but one of the topics on which he leaves the reader with important unsolved problems to ponder (I should acknowledge that the emotions are the main topics of earlier and later, more technical books by de Sousa).

© 2012 Ed Brandon

Ed Brandon is, by training, a philosopher, and now is working in a policy position in the University of the West Indies at its Cave Hill Campus in Barbados.