Oct 07 2010

The Nature of Consensus

Anti-scientific creationist propaganda is always a good source of unintentional irony. Recently at the Disco-Tute’s propaganda blog they posted a piece about scientific consensus, prompted by a recent study on the public reaction to scientific consensus.

The study, by Dan Kahan et al., finds that the public may be sharply divided on factual questions about which the scientific community largely agrees, like evolution, global warming, and nuclear waste. The authors explored the reason for this disconnect and found that members of the public tend to form their beliefs about the existence of a scientific consensus based upon their cultural views.

This certainly reflects common experience – the acceptance or denial of the existence of a scientific consensus on man-made global warming tracks with political ideology. It seems unlikely that individuals are mostly making independent and rational assessments of the scientific evidence, and just happen to be coming up with the conclusion that is favored by the ideological culture in which they are embedded. It is a common conceit, however, that one’s own views are rationally evidence-based, and it is the other side that is ideological.

Of course this is not a symmetrical phenomenon. Some ideologies may have little or no impact on certain scientific questions, while others may have a dominant impact on the same questions. Therefore, on specific issues some ideologies may be more “free” to simply follow the scientific consensus, while others will have a firmly pre-determined bias.

In any case, the relationship between science and consensus is a complex one. I discuss that relationship at length here, and so will not repeat those points. (Do read the other article if you want to delve into that issue further.)

What the current study shows is that when the scientific consensus conflicts with ideological belief, most people will happily reject the consensus. At such times there are readily available excuses for such rejection – scientists are wrong sometimes, scientists are people too and have their own biases, the media is mis-reporting the state of the science, or the scientific community is dominated by conflicts of interest (from government, industry, or professional protectionism).

There is a kernel of truth to all of these accusations, making them all the more powerful as rationalizations. However, often they are invoked ad hoc to justify an ideological belief, rather than in reaction to an independent assessment of the overall impact of such factors on a specific question. Throw in a little confirmation bias – and it’s easy to see how the public can be so polarized over what are essentially empirical questions that should be objectively resolvable.

Of course, the  Disco-Tute does not appear to be interested in a fair assessment of scientific consensus. They are an ideological organization, and so need to defend their ad hoc dismissal of scientific consensus whenever it suits their needs. In response to the Kahan study, they write (there is no specific author listed for this article):

Isn’t that special?  So if you’re a Darwin doubter it’s not because you’ve thought through the issue for yourself and come to a heterodox conclusion. You’re just a sheep, following what your hick friends and neighbors say.

That statement is intended to be sarcastic, but is actually more ironic, because in a way it is exactly correct. Another  possible interpretation is that every evolution denier (or at least most) came to a thoughtful, but horribly wrong, conclusion about the scientific evidence. It is extremely unlikely that independent scientific conclusions would track so closely with religious beliefs and political ideology.

Logically, the other possibility is that it is those who accept the consensus on evolution who are influenced by ideology, while religious conservatives are being scientifically objective. Or maybe the evidence is inconclusive, leaving everyone to follow their biases.

A full discussion of the scientific merits of evolution are beyond this post, so suffice it to say I have written before on aspects of the evidence for evolution and arguments against it. The evidence for the fact of evolution is overwhelming.

This is not just my opinion, it is the overwhelming consensus of scientific opinion. But of course, the Disco-tute has an answer for that:

Notice, however, the utter naïveté of the study and report. Basically, Professor Kahan et al. say that people in the general public tend to count a scientist as an expert if that scientist supports the views of the group the individual belongs to. But they treat the scientists themselves as if they aren’t a part of the general public and so don’t have the same bias. Apparently, scientists alone are immune to the bias detected in the study that is otherwise unbiquitous.

The author is missing a major premise of the study, however – that on certain issues the scientific community is united on one conclusion while the public is divided on the same issue. The public is divided because they are generally following their ideology and biases, and the scientific community is united because they are generally following scientific evidence and logic. That is a crucial point – the scientific community is united behind a solid consensus, despite the fact that they do range the spectrum of ideological biases just like the public.

Individual scientists may be biased by their beliefs and ideology, and there are always dissenters and outliers. But science has a process, with rules of logic and evidence. That’s kinda the point of science. And it is reasonable to believe that trained scientists are likely to have a better appreciation for the process of science, and the details of the findings of science, than the general public.

But the Disco-tute would have you believe that the scientific opinions of the average citizen are just as reliable as the consensus of opinion of experts who have spent years or decades studying scientific methodology and their particular fields in great depth and detail.

Of course, they need to perpetuate that notion because their job is to deny well-established science in the name of their particular ideology.

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