Think about it

By "dangerous ideas" I don't have in mind harmful technologies, like those behind weapons of mass destruction, or evil ideologies, like those of racist, fascist or other fanatical cults. I have in mind statements of fact or policy that are defended with evidence and argument by serious scientists and thinkers but which are felt to challenge the collective decency of an age. The ideas listed above, and the moral panic that each one of them has incited during the past quarter century, are examples. Writers who have raised ideas like these have been vilified, censored, fired, threatened and in some cases physically assaulted.

Every era has its dangerous ideas. For millennia, the monotheistic religions have persecuted countless heresies, together with nuisances from science such as geocentrism, biblical archeology, and the theory of evolution. We can be thankful that the punishments have changed from torture and mutilation to the canceling of grants and the writing of vituperative reviews. But intellectual intimidation, whether by sword or by pen, inevitably shapes the ideas that are taken seriously in a given era, and the rear-view mirror of history presents us with a warning.

Time and again, people have invested factual claims with ethical implications that today look ludicrous. The fear that the structure of our solar system has grave moral consequences is a venerable example, and the foisting of "intelligent design" on biology students is a contemporary one. These travesties should lead us to ask whether the contemporary intellectual mainstream might be entertaining similar moral delusions. Are we enraged by our own infidels and heretics whom history may some day vindicate?