Lectory » On Experts and Global Warming

Tue 12 July 2011ShareComment

The Stone is featuring occasional posts by Gary Gutting, a professor of philosophy at the University of Notre Dame, that apply critical thinking to information and events that have appeared in the news.

Experts have always posed a problem for democracies. Plato scorned democracy, rating it the worst form of government short of tyranny, largely because it gave power to the ignorant many rather than to knowledgeable experts (philosophers, as he saw it). But, if, as we insist, the people must ultimately decide, the question remains: How can we, nonexperts, take account of expert opinion when it is relevant to decisions about public policy?

To answer this question, we need to reflect on the logic of appeals to the authority of experts. First of all, such appeals require a decision about who the experts on a given topic are. Until there is agreement about this, expert opinion can have no persuasive role in our discussions. Another requirement is that there be a consensus among the experts about points relevant to our discussion. Precisely because we are not experts, we are in no position to adjudicate disputes among those who are. Finally, given a consensus on a claim among recognized experts, we nonexperts have no basis for rejecting the truth of the claim.

These requirements may seem trivially obvious, but they have serious consequences. Consider, for example, current discussions about climate change, specifically about whether there is long-term global warming caused primarily by human activities (anthropogenic global warming or A.G.W.). All creditable parties to this debate recognize a group of experts designated as “climate scientists,” whom they cite in either support or opposition to their claims about global warming. In contrast to enterprises such as astrology or homeopathy, there is no serious objection to the very project of climate science. The only questions are about the conclusions this project supports about global warming.

There is, moreover, no denying that there is a strong consensus among climate scientists on the existence of A.G.W. — in their view, human activities are warming the planet. There are climate scientists who doubt or deny this claim, but even they show a clear sense of opposing a view that is dominant in their discipline. Nonexpert opponents of A.G.W. usually base their case on various criticisms that a small minority of climate scientists have raised against the consensus view. But nonexperts are in no position to argue against the consensus of scientific experts. As long as they accept the expert authority of the discipline of climate science, they have no basis for supporting the minority position. Critics within the community of climate scientists may have a cogent case against A.G.W., but, given the overall consensus of that community, we nonexperts have no basis for concluding that this is so. It does no good to say that we find the consensus conclusions poorly supported. Since we are not experts on the subject, our judgment has no standing.

It follows that a nonexpert who wants to reject A.G.W. can do so only by arguing that climate science lacks the scientific status needed be taken seriously in our debates about public policy. There may well be areas of inquiry (e.g., various sub-disciplines of the social sciences) open to this sort of critique. But there does not seem to be a promising case against the scientific authority of climate science. As noted, opponents of the consensus on global warming themselves argue from results of the discipline, and there is no reason to think that they would have had any problem accepting a consensus of climate scientists against global warming, had this emerged.

Some nonexpert opponents of global warming have made much of a number of e-mails written and circulated among a handful of climate scientists that they see as evidence of bias toward global warming. But unless this group is willing to argue from this small (and questionable) sample to the general unreliability of climate science as a discipline, they have no alternative but to accept the consensus view of climate scientists that these e-mails do not undermine the core result of global warming.

I am not arguing the absolute authority of scientific conclusions in democratic debates. It is not a matter of replacing Plato’s philosopher-kings with scientist-kings in our polis. We the people still need to decide (perhaps through our elected representatives) which groups we accept as having cognitive authority in our policy deliberations. Nor am I denying that there may be a logical gap between established scientific results and specific policy decisions. The fact that there is significant global warming due to human activity does not of itself imply any particular response to this fact. There remain pressing questions, for example, about the likely long-term effects of various plans for limiting CO2 emissions, the more immediate economic effects of such plans, and, especially, the proper balance between actual present sacrifices and probable long-term gains. Here we still require the input of experts, but we must also make fundamental value judgments, a task that, pace Plato, we cannot turn over to experts.

The essential point, however, is that once we have accepted the authority of a particular scientific discipline, we cannot consistently reject its conclusions. To adapt Schopenhauer’s famous remark about causality, science is not a taxi-cab that we can get in and out of whenever we like. Once we board the train of climate science, there is no alternative to taking it wherever it may go.

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