As law professor Dan Kahan and his colleagues at the Yale Cultural Cognition Project have shown, the strong urge to avoid scientific and technological risk is far more characteristic of people who have egalitarian and communitarian values, that is to say, left-leaning folks. As I reported earlier, according to research by Kahan and his colleagues individualists tend to dismiss claims of environmental risks because they fear such claims will be used to fetter markets and other arenas of individual achievement. Hierarchicalists tend to see claims of environmental risk as a subversive tactic aiming to undermine a stable social order. In contrast, Egalitarians and Communitarians dislike markets and industry for creating disparities in wealth and power. In fact, they readily believe that such disparities generate environmental risks that must be regulated.

In other words, everybody has values that they are anxious to protect and everybody, including liberals, struggles with confirmation bias. The operation of the scientific process is the only truly effective way humanity has developed for overcoming confirmation bias and figuring out reality. In most cases it can reduce, but not eliminate, uncertainties, and correct mistakes as we go along. Unfortunately, as the autism/vaccine incident shows, unscientific approaches like the precautionary principle actually feed into the confirmation biases associated with a specific ideological tendency.

Lest anyone think that I’m defending Republicans, I will point to my various critiques of Republican views with regard to stem cell research, biological evolution, and climate change. Finally, the question recurs: Who is more anti-science, Democrats or Republicans? On the specific issues discussed above, I conclude that the Republicans are more anti-science. However, I do also agree with Berezow that scientific “ignorance has reached epidemic proportions inside the Beltway.”