Monday, March 25, 2013

On Scientific Consensus

It's hemlock for those who don't defend the status quo

According to historian David Hackett Fischer, historians are susceptible to falling victim to the fallacy of the prevalent proof, which "makes mass opinion into a method of verification."

There are at least a few historians [Fischer writes] who would make a seminar into a senate and resolve a professional problem by resorting to a vote. I witnessed one such occasion (circa 1962) as a student at the Johns Hopkins University. A scholar who was baffled by a knotty problem of fact literally called for a show of hands to settle the question. An alienated minority of callow youths in the back of the room raised both hands and carried the day, in defiance of logic, empiricism, and parliamentary procedure. [pg. 52 of Fischer's Historian's Fallacies]

It's not just a problem for historians, however. Scientists often appeal to the idea of a scientific consensus--a hypothesis or theory generally accepted as truth by a majority of scientists. Anthropogenic climate change comes to mind, as does the lipid hypothesis of cardiovascular disease. (Regarding the latter, see this, for example.)

But it's important to remember that mass opinion, even if the opinion belongs to highly educated scientists, is not the same thing as empiricism. Paradigms shift with new evidence. Scientific hypotheses are always tentative and must be continuously challenged, debated, refined, and sometimes rejected, not merely voted on (if only implicitly).

If only the progress of science were at stake then there would be little harm in the appeal to scientific consensus, but, sadly, it's often invoked for political purposes. Where there's politics there's policies, and as a student of science, I should be concerned with the politicizing of science and the enlistment of the strong arm of Government to enact and enforce policies based on its ever-tentative hypotheses, even when scientific consensus exists.

Do I have any better ideas? Nope. I'm just saying.

(For interesting reads on what happens when someone, in this case a philosopher, bucks scientific consensus, see this and this.)