No consensus on “consensus”

Posted on timeOctober 19th, 2007 by userPali Gap

When scientists do “philosophy of science” (meta-science) they can often be very naive. Many science text books will include in their introduction a quick theory of knowledge. In the past the stock explanation for “how science works” might be a simple empiricism: “we start out by making some observations. From these we deduce a theory. Further observations confirming the theory then establish that the theory is true“.

It seems to me that one of the by-products of the global warming debate has been the addition of the idea of consensus into the theory of science. Given that the global warming debate is about highly politicised science, perhaps it should come as no surprise that a concept fundamental to political progress (consensus) gets assumed to be at the heart of scientific progress.

(Of course “Consensus” is also one of those Orwellian newspeak feel-good words which modern politicians deploy because it seems to make its own argument).

The alternative view, as wonderfully expounded by Karl Popper for example, stresses the adversarial nature of science. On this view we should (insofar as we wish to think scientifically) never cease to challenge the consensus, to find refutations and look for critical tests. The best theories will be the ones still standing after exposure to the most powerful scepticism. Those who seek to shield their ideas from criticism by, for example, invoking a “closed shop” of men in white coats who alone are qualified to speak on the issue are being profoundly un-scientific. You see this attitude from latter-day warming-mongers like this:

  • “You claim AGW is scientific fact because there is an overwhelming consensus. But what about scientist …..(insert name) who disagrees?” Ah, but he is in the wrong department/in the wrong field/ retired/has a great aunt whose third cousin believed in creationism (delete as appropriate)
  • “But what about this scientist……. (insert name). He is an expert in the field!” Ah, but although he makes these claims, they have not been published in a peer-reviewed journal
  • “But what about this scientist………(insert name)? His work is published in…. (insert peer-reviewed journal)!” Ah, but those are the wrong peers and this is the wrong journal!

A wonderful critique of “consensus” has just been published by John Kay. Here are some things he has to say:

“Consensus finds a way through conflicting opinions and interests. Consensus is achieved when the outcome of discussion leaves everyone feeling they have been given enough of what they want. The processes of proper science could hardly be more different. The accomplished politician is a negotiator, a conciliator, finding agreement where none seemed to exist. The accomplished scientist is an original, an extremist, disrupting established patterns of thought. Good science involves perpetual, open debate, in which every objection is aired and dissents are sharpened and clarified, not smoothed over.”

And: “We do not say that there is a consensus over the second law of thermodynamics, a consensus that Paris is south of London or that two and two are four. We say that these are the way things are.”

And: “Peer review is a valuable part of the apparatus of scholarship, but carries a danger of establishing self-referential clubs that promote each other’s work.”

And: “The notion of a monolithic “science”, meaning what scientists say, is pernicious and the notion of “scientific consensus” actively so. The route to knowledge is transparency in disagreement and openness in debate. The route to truth is the pluralist expression of conflicting views in which, often not as quickly as we might like, good ideas drive out bad. There is no room in this process for any notion of “scientific consensus”.


John Kay is one of Britain’s leading economists


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