Quick Note on Sunstein and the Precautionary Principle

This is further to Jim’s post below on the Precautionary Principle and climate change; it also goes obliquely to a couple of Eric’s posts on the climate change debates.  I’ve been meaning to raise Cass Sunstein and his very interesting book Worst-Case Scenarios in this context, but I’ll be very brief.

Jim points out that Friedman wants to “go Cheney on climate change” – meaning by that, Vice-president Cheney famously embraced the so-called 1% doctrine, according to which if some horribly, truly unacceptable catastrophe has a 1% chance of happening, you have to treat it as 100%.  Sunstein points out, correctly, that Cheney has a potential contradiction here, because although that is his stance regarding terrorism, it is not his position regarding climate change.  Cheney would have a response in this debate, that a single discrete event, such as a catastrophic terrorist attack, or even a series of them, is not really like the diffuse accumulation of changes over a long term that constitutes climate change.  Several commentators made that observation with respect to Eric’s asteroid post, and I don’t want to carry that discussion further here, though I do think the disanalogies are very important in dealing with policy.

What I wanted to point out is that Friedman characterizes Sunstein’s view as follows:

[T]he legal scholar Cass Sunstein, who then was at the University of Chicago, pointed out that Mr. Cheney seemed to be endorsing the same “precautionary principle” that also animated environmentalists. Sunstein wrote in his blog: “According to the Precautionary Principle, it is appropriate to respond aggressively to low-probability, high-impact events — such as climate change. Indeed, another vice president — Al Gore — can be understood to be arguing for a precautionary principle for climate change (though he believes that the chance of disaster is well over 1 percent).”

Friedman goes on to endorse the Cheney view as applied not to terrorism, but to climate change.  What he does not mention is that Sunstein has an entire book, Worst-Case Scenarios, explaining why the Precautionary Principle is a bad idea whether applied to terrorism or to climate change.  Sunstein’s book substitutes for the Precautionary Principle a far more subtle and complicated set of principles instead, principles that go precisely to the issues above that Friedman bulldozes over in the name of urging Cheney-ism with respect to climate change.  (I, at least, did not think that evident from the Friedman column; one might have come away plausibly thinking that Friedman thought Sunstein would agree with him.)

Sunstein does, I take it, think climate change is real and that serious steps ought to be taken, perhaps even exactly those that Friedman urges.  Those steps are much more, I also take it, than, say, a CBA consequentialist such as Bjorn Lomborg would see as justified.  But certainly Sunstein does not reach whatever his exact views are on the basis of Friedman’s simplistic reasoning.  (Friedman quotes from Sunstein’s blog but, with all respect to our scholarly blogging, sometimes one needs to read the book.)  I won’t try to do justice to the many steps in Sunstein’s view, but just quote from early in the book (p. 14):

[N]otwithstanding its international influence, the Precautionary Principle is incoherent; it condemns the very steps that it requires.  To see the point, imagine if we adopted a universal One Percent Doctrine [Cheney doctrine], forbidding any course of action that had a 1 percent chance of causing significant harm.  The likely result would be paralysis, because so many courses of action would be forbidden.  (Even doing nothing might be prohibited…) But narrower and better precautionary principles can be devised.

Sunstein’s insight here is the incoherence of the Precautionary Principle, in the form that Friedman (or Cheney) endorses it; it can’t be universalized as a guide to action.  I have some problems with the alternatives provided in the book – to some extent, it seems as though principles are introduced ad hoc.  I also don’t think the discussion of catastrophic terrorism is correct – although, to be sure, climate, not terrorism is really the focus of Worst Case Scenarios – for reasons that I discuss in part here (not brilliantly, alas, but anyway it makes this point).  In any case, Sunstein is no fan of the Precautionary Principle as endorsed by Friedman – an observation that I think is more than merely pedantic.