The main source of political nervousness in discussions about heritability is its possible implications for race differences. John Searle echoed a widespread view: “once you believe that there are innate human mental structures it is only a short step to argue that the innate mental structures differ from one race to another” (Searle 1976).

The fact that the step from individual heritability to group heritability is perceived as “short” may explain the occasionally acrimonious opposition to claims about individual heritability: better to stop the inference at an early stage than to find oneself in the position where later, after conceding too much, one no longer has a good strategy to resist the abominable conclusion. But whatever resistance could be expected at the level of general discussions about heritability, the situation dramatically changes when race differences are addressed explicitly. Linda Gottfredson conveys the mood well: “One can feel the gradient of collective alarm and disapproval like a deepening chill as one approaches the forbidden area” (Gottfredson 1994: 56).

The most alarming hypothesis, of course, is the explosive mix of three ideas: race, IQ, and heritability.