chemistry with math during his student years at the University of Vienna, where he earned his doctorate in 1988. He soon moved on to Oxford, where he eventually became head of the mathematical biology program. I visited him in Princeton in the fall of 1998 to inquire about the institute’s plans for mixing math with the science of life.
Nowak described a diverse research program, touching on everything from the immune system—deciphering the math behind fighting the AIDS virus, for instance—to inferring the origins of human language. Underlying much of his work was a common theme that at the time I really didn’t appreciate: the pervasive relevance of game theory.
It makes sense, of course. In biology almost everything involves interaction. The sexes interact to reproduce, obviously. There are the fierce interactions of immune system cells battling viruses, or toxic molecules tangling with DNA to cause cancer. And humans, of course, always interact—cooperatively or contentiously, or just by talking to each other.
Evolutionary processes shape the way that such interactions occur and what their outcomes will be. And that’s a key point: Evolution is not just about the origin of new species from common ancestors. Evolution is about virtually everything in biology— the physiology of individuals, the diversity of appearances within groups, the distribution of species in an ecosystem, and the behavior of individuals in response to other individuals or groups interacting with other groups. Evolution underlies all the biological action, and underlying evolution’s power is the mathematics of game theory. “Game theory has been very successfully used in evolution,” Nowak told me. “An overwhelming number of problems in evolution are of a game-theoretic nature.”3
In particular, game theory helps explain the evolution of social behavior in the animal (including humans) kingdom, solving a perplexing mystery in the original formulation of Darwinism: Why do animals cooperate? You’d think that the struggle to survive would put a premium on selfishness. Yet cooperation is common in the biological world, from symbiotic relationships between para-