Over at The Corner, Jerry Taylor writes about a recent public letter signed by over 100 scientists who are skeptical about global warming. This was written in response to President Obama's assertion that there is no serious dispute over anthropogenic global warming among scientists.
Leaving aside the global warming debate, I want to focus in on one of Taylor's statements, in which he accuses critics of these global warming skeptics of fallacious reasoning:
More experts disagree with so-and-so than agree — So what? Not only is this a variation of the argument above, it also assumes that truth can be reliably determined by a show of hands. Nothing — especially in science — could be further from the truth.
An argument’s merit has nothing to do with the motives of the arguer, the credentials of the arguer, or the popularity of the argument. Full stop. No exceptions.
Emphasis in the original. Now I agree with Taylor in principle that it is illogical to judge an argument based upon the number of people who support it. Truth is truth, whether no one believes it or everyone believes it. If everyone rejected the notion that the tides are caused by the moon's gravitational pull, but were instead caused by water pixies, then everyone would be wrong.
But it's not that simple.
When a non-scientist is examining scientific assertions -- or, more broadly, a layperson is dealing with the assertions of highly specialized scholars -- the non-scientist is always addressing other people's facts.
Like it or not, we scientific laypeople are not equipped with the knowledge to make reasonable judgments on anthropogenic global warming (contra another one of Taylor's more bizarre arguments: that a scientist does not need to have personally studied global warming in order to assess it). We can't judge the information because it's too complex without undertaking many years of study. So all we can do is evaluate the source of that information.
Doing so involves, despite Taylor's wishes, a popular consensus. If 99 scientists say that a certain thing is true, and 1 scientist says that it is false, and we cannot assess the information ourselves, we can only conclude that the lone scientist is a crackpot and the 99 are correct. We and the 99 scientists might be wrong, but we laypeople have no better way of evaluating scientific information.
As Taylor argues, this is a logical fallacy. It is, however, the only option open to us. Unless, of course, Taylor would like to prove -- without consulting outside sources -- that tides are caused by lunar gravitation instead of water pixies.
Could this be done? Possibly. But as a layperson in the natural sciences, I would have no idea how to do so without examining the work of scientists -- that is, I would have no way of personally knowing without that knowledge being based upon other people's facts. And without many years of dedicated study, I could never understand lunar gravitation well enough to assess its reality better than the scientists who would be teaching me. Again, as in global warming, I would not be understanding the scientific phenomena myself, but evaluating the judgment of people explaining those scientific phenomena.
Taylor concludes his post with:
I don’t mean to suggest that climate alarmists are (necessarily) any more prone to this sort of thing than any other policy crusader populating the blogosphere. But I find it rich to see these people loudly tell me that they’re the smart experts whose judgment should govern when even at the most fundamental level they can’t seem to think straight.
Over the years of blog debating, I've found that it's possible to toss out logical fallacy accusations like rhetorical hand grenades. That may lead to logical thinking, but it doesn't always lead to reasonable thinking. Taylor's post is a good example. It may not be logical to attribute truth to the popular consensus of qualified experts, but it is a reasonable action to take if becoming an expert oneself is not feasible.