early 20th centuries. Academic response In a letter to Slate magazine, Harvard University psychology professor Steven Pinker wrote: The suggestion that scholars "can't ignore bad ideas" is a nonstarter. In science there are a thousand bad ideas for every good one. "Doing battle" against all of them is not an option for mere mortals, and doing battle against some of them is a tacit acknowledgment that those have enough merit to exceed the onerous threshold of attention-worthiness. MacDonald's ideas, as presented in summaries that would serve as a basis for further examination, do not pass that threshold, for many reasons: 1. By stating that Jews promulgate scientific hypotheses because they are Jewish, he is engaging in ad hominem argumentation that is outside the bounds of normal scientific discourse and an obvious waste of time to engage. MacDonald has already announced that I will reject his ideas because I am Jewish, so what's the point of replying to them? 2. MacDonald's main axioms – group selection of behavioral adaptations, and behaviorally relevant genetic cohesiveness of ethnic groups – are opposed by powerful bodies of data and theory, which Tooby, Cosmides, and many other evolutionary psychologists have written about in detail. Of course any assumption can be questioned, but there are no signs that MacDonald has taken on the burden of proof of showing that the majority view is wrong. 3. MacDonald's various theses, even if worthy of scientific debate individually, collectively add up to a consistently invidious portrayal of Jews, couched in value-laden, disparaging language. It is impossible to avoid the impression that this is not an ordinary scientific hypothesis. 4. The argument, as presented in the summaries, fails two basic tests of scientific credibility: a control group (in this case, other minority ethnic groups), and a comparison with alternative hypotheses (such as Thomas Sowell's convincing analysis of "middlemen minorities" such as the Jews, presented in his magisterial study of migration, race, conquest, and culture). Pinker closed by commenting that he had "not plowed through MacDonald's trilogy and therefore run the complementary risks of being unfair to his arguments, and of not refuting them resoundingly enough." A paper by David Lieberman, a Holocaust researcher at Brandeis University, alleges that MacDonald has distorted evidence and chosen evidence selectively for rhetorical purposes. John Tooby, past president of the Human Behavior and Evolution Society and a professor of anthropology at the University of California,