“Taboo” is a word associated with anthropology. If something is “taboo,” it may not be used, eaten, or discussed due to cultural, rather than legal, prohibitions.

Cultural taboos create some tension when they constrain inquiry. However, they continue to survive in the academic, intellectual, and scientific worlds. Although I studied anthropology as a grad student, I learned the strength of taboos from my Ph.D. advisor, a professor of political economy. He burned my final term paper upon submission, a serious statement in the days before Xerox and PCs.

“Why,” I asked Professor Siffin, “did you burn my paper? Was it that bad?”

“Oh no,” he responded. “It was clearly an A, maybe better. You just can’t write about such things. Doing so would follow and brand you and I can’t let that happen. The best thing to do was to burn it, so I did.”

Today, James Watson, the co-discoverer of DNA, and Larry Summers, former president of Harvard, could well attest to the power of taboos. They and others who break taboos pay the price for their violations.

At a 2005 National Bureau of Economics Research conference, Summers had the temerity to suggest that the only explanation for why men outnumber women as professors of math, science, and engineering at our top universities might not be discrimination. He said, “It does appear that on many, many different human attributes–height, weight...overall IQ, mathematical ability, scientific ability–there is relatively clear evidence that whatever the difference in means...there is a difference in the standard deviation and variability of a male and a female population.”

In simple terms this means there are far more morons and geniuses among males than females. And, of course, only the very brightest of either sex achieve high success in these difficult scientific fields. Despite his many accomplishments (among the youngest ever tenured at Harvard, Clinton’s Secretary of Treasury, and much more), Summers was fired for breaking a strong taboo. Even today he is persona non grata as a university speaker.

Summers did not understand an important, politically correct, cultural truth: the genders really are equal. Only discrimination accounts for differences. He sinned and even his self-demeaning sniveling didn’t save him. Summers will long pay for suggesting that the talents of males and females may not be identical.

Only a female can make Summers’ claim with impunity. For example, Susan Greenfield, director of London’s Royal Institution, can assert that “nothing should stop you ascertaining the scientific truth; science must be free of concerns about gender and race.” James Watson was too optimistic when predicting “that the time was surely not far off when academia would have no choice but to hand political correctness back to the politicians.”

Harvard professor Steven Pinker provides the scholarly ideal. He says, “Look, the truth cannot be offensive. Perhaps the hypothesis is wrong, but how would we ever find out whether it is wrong if it is 'offensive' even to consider it? People who storm out of a meeting at the mention of a hypothesis, or declare it taboo or offensive without providing arguments or evidence, don't get the concept of a university or free inquiry."

However, there is always a gap between ideal and actual behavior. Political and bureaucratic forces often reinforce cultural “truths.” We’re seeing this in conflicts over global warming when dissenters from “consensus” are lumped with Holocaust deniers. Such censorship strongly implies feelings of intensity and insecurity.

Al Gore has defined the acceptable, politically correct position on climate change: CO2 is a form of pollution, it causes global warming, humans generate it, all the Earth’s ecology will suffer if we don’t redeem our culture, repent our sinful lifestyles, and reduce our carbon footprints.

Two environmentalists, Ted Nordhaus and Michael Shellenberger, have challenged this conventional political wisdom on climate change in their new book Breakthrough: From the Death of Environmentalism to the Politics of Possibility. I believe theirs is the most creative and constructive environmental book in the past decade. Will mainstream Greens demonstrate sufficient intellectual integrity and honestly consider their argument, or will they dismiss it for breaking a taboo?