Rationality is under assault. This assault has reached beyond politics, international
relations, and even personal relationships into the inner recess of economics, where
books like Dan Ariely’s “Predictably Irrational” take their place on the best-seller
list. One gets the sense that in the popular culture that people are irrational at best,
dishonest, self-deceptive, and deluded at worst.
On the flip side, as biology becomes more mechanistic, abstract concepts like
rationality seem to make less and less sense. In the era of molecular biology, organisms
look like complex dynamical systems made up of an ensemble of interacting molecules,
and their behavior is an emergent property of the rules that those molecules follow.
Evolution does not operate on anything so grand as rationality, but instead on the rate
constants underlying those rules, and is itself a dynamical system, and a rather noisy
one at that, which lurches in the general direction of increasing fitness even in the face
of genetic drift and changing environments.
The edited volume “Evolution and Rationality” thus appears at an interesting time.
Okasha and Binmore have assembled an eclectic set of chapters that take on the apparent
connection between rationality and evolution as two mechanisms to produce optimal
responses to the environment. For me, the book seemed pleasantly old-fashioned,
and served as a useful reminder that the mechanistic reductionism that I personally have
accepted, without a great deal of rational thought but more due to its short term payoff,
is of course not the whole target of inquiry in theoretical biology. I also found the mix
of articles by biologists, economists, and philosophers of science to be challenging,
reminding us that ideas that appear superficially simple have essential subtleties.
In any edited volume, the chapters vary widely in how effectively they hit the
mark. For me, the chapter by Brighton and Gigerenzer on rational actor models in

• Samir Okasha, and Ken Binmore (eds): Evolution and rationality: decisions, co-operation and strategic behaviour