Battles between orthodoxy and non-conformity are never won or lost. Only a naïve empiricist, or a religionist who confidently expects all to be made clear at the final trump—when the prizes are handed out, truth is consoled and error consumed by shame—could suppose otherwise.
There will be no “killer blow” to either the alarmist or sceptical side of disputes over the future of the climate. Neither better knowledge of underlying mechanisms, nor longer nor more subtle measurement will discover an Answer. Empiricism underdetermines the truth (I see that Sinclair Davidson agrees).
But if wrangling over the science of future climate is headed for an indeterminate stand-off, can we nonetheless expect governments to make rational, proportionate public policies? How?
Ultimately, we are “short-changed” by the acts of perception, as well as by our epistemology, such that some model of the world must stand between us and shared experience; forming and filtering the world. So each of us is, at best, a model-dependant realist. Two and a half millennia since Aristotle legislated the problem (“Ineluctable modality of the visible”, in Stephen Deadalus’ gloss, “… thought through my eyes”) it’s finally a commomplace that our models are inconsistent and incomplete and break down when pushed. Even the most refined cosmologies now depend on five-fold mashups (M‑theory), or multiple inconsistent (quantum theory, general relativity) and, unavoidably, incomplete but successful (Newtonian) descriptions.
This is not evidence that science is “socially constructed”, much less that its propositions should be scrutinised through an obscure semiotic lens. It’s the everyday experience of conflict between careful arguments based on “hard facts” that —as Einstein, as much as Sam. Johnson, held—are unarguably persistent.
What chance that observation will reconcile the evangelical dread of the alarmists and the show-me scorn of the sceptics? None. What can we expect, then, from public policy? Confusion? “Precaution”? A naïve insistence—in the face of daily witness to the contrary—that science will ensure every gordian knot has one, and only one, solution (Alexander’s solution was trenchant, but obtuse, uninformative)?
Taken so far, this argument might seem to lead to despair; if we can’t know anything for sure what’s the point of debate about rational policy options? But the above is merely an especially hard-edged statement of the epistemic problem of all public policy (private decisions are a different matter; le coeur a ses rasions). Any thoughtful public policy decision-maker regularly faces unresolved conflicts, insufficient data and good arguments for contrary courses especially in the face of uncertainty. This is the normal case. Ross Garnaut is exaggerating if he means that climate change is the only “diabolical problem”.
There is, in fact, plenty of need for informed debate despite the probability of un-resolved conflict. Although we will never have a “consensus view” (it’s nonsense to speak of physical science in this way) we certainly need not despair of having better knowledge in the future or of having more or lower-cost options and possibly (history shows us) different priorities.
The rules for the best public policy-making in the face of uncertainty and potentially costly choices are well-known and apply equally to emissions-control as they do to public health or industry assistance. They do not include rushing into high-cost, potentially futile, single-option “solutions” intended to signal bona fides to the United Nations.