A book on heritability without a chapter on political issues would be a bit like Hamlet without the ghost of Hamlet's father. Even when the ghost of politics is not addressed at all, it always lurks in the background, haunting the protagonists and influencing both the tone and dynamics of the heritability controversy.

But why not exorcise the ghost from the debate once and for all? For, if we want to understand heritability as a scientific concept, is it not advisable to isolate it from vagaries of political storms that only create confusion, distrust, and anger? There are two problems with this idea. First, since in the discussions about heritability, politics has occupied center stage so forcefully and for so long, we can hardly make sense of what went on if we neglect such an important element in the story, however irrelevant it may “objectively” be for the issue at hand. And second, before looking into these matters more carefully, we cannot actually be sure that heritability research is indeed devoid of political implications, as many people keep telling us.

A good way to start this chapter is to consider two frequently used arguments to cross the barrier between science and politics: first, the claim that a scientific belief is mistaken because it is politically motivated, and second, the claim that a scientific belief is politically motivated because it is mistaken.