1. Human Nature and the Limits of Human Possibility
1. In the context of evolutionary psychology, the term sex is usually used narrowly: sex is a matter of gamete size.
2. The Cost of Change
1. Reading this final category of costs broadly, we can see it as encompassing some of the others. Happiness and at least the subjective feeling of freedom are themselves phenotypic traits that can be traded off against others. Because of the special roles that happiness and freedom play in ethical thought, however, it is more useful here to treat them separately.
3. Thinking About Change and Stability in Living Systems
1. For this proportionality of cause to effect to hold in general requires not only that the causal factors combine additively but also that they act linearly. In mathematical terms, additivity actually follows from linearity so the strong sense of “addition” of causal factors that I describe here really amounts to the presumption that the causal function of genotype and environmental variables that determines the phenotype is a linear one.
2. In the technical language of causal theory, this sort of addition of causes is not classified as interaction. Interaction in the technical sense occurs precisely when the causal factors combine nonadditively so that a genetic difference may play out differently in different environments; an environmental difference may have different consequences for different genotypes. I’ve followed Godfrey-Smith’s usage here in including addition under the rubric of interaction because doing so usefully emphasizes that addition of causes is a limiting case of a much broader range of possible ways in which the internal and external factors can combine.
3. Lewontin attributes this remark to Arturo Rosenblueth and Norbert Wiener (1945), but it does not appear there.
5. Human Possibilities
1. How rare the strategy will be depends on the payoffs associated with conflict. If the cost of conflict is high enough, hawks may be the rare variant. But for the kinds of values often assumed in these models, the dove strategy will persist only at a low frequency. The key point is that this way of explaining desirable traits that are now rare implies that they cannot be stably maintained at frequencies much higher than what we now observe.