Incompleteness and the precautionary principle
As commenters and my last post, and others, have pointed out, there’s a logical gap in my argument that, given imperfect knowledge and the recognition that we tend to overestimate our own capabilities, we should adopt a rule-based version of consequentialism which would include rules against pre-emptive or preventive wars. The problem of imperfect knowledge also applies to the consequences of deciding not to start a pre-emptive war. As I’ll argue though, the symmetry is only apparent and the case for caution is strong.
I’ve addressed the underlying issue at length in a
recent paper (large PDF) trying to make sense of the well-known “precautionary principle” used in relation to poorly-understood environmental risks. I look at a range of decision procedures, from the simplest (guess what is most likely to happen and assume that will happen) through the simplistic treatment of uncertainty given by expected value models to more general approaches incorporating the recognition that, in most real world problems we will not know the probabilities of the possible outcomes and will not even have considered all the possible outcomes. Moreover, because surprises are generally unpleasant, the things that are omitted are likely to produce an overoptimistic evaluation. This leads me to state a general incompleteness hypothesis, namely
Estimates of project outcomes derived from formal models of choice under uncertainty are inherently incomplete. Incomplete estimates will generally be over-optimistic. The errors will be greater, the less well-understood is the problem in question.
The last sentence is crucial. In the context of an argument for pre-emptive war, the relevant alternative is “wait and see”. Whereas the consequences of going to war are highly unpredictable, the consequences of wait and see, over a period of, say, a few months, aren’t hard to describe. Either the putative threat will get worse, or it will fade. The cost of the wait and see approach is the possibility of having too fight later, with a less favorable balance of forces than could have been had with the pre-emptive strike. But advocates of the pre-emptive strike tend to overstate these costs and underestimate the uncertainty surrounding their preferred option.
Iraq provides a good illustration. At the time Bush and Blair decided on war, the alternative was to wait for Blix’s inspections to be completed. The reasons given for going to war in March 2003 rather than waiting until later seem absurdly trivial in retrospect. It was argued that the invasion couldn’t take place in summer and that waiting until after summer would keep forces tied up too long on standby in Kuwait. As things turned out, I’m sure Coalition forces would have far preferred summer in Kuwait to summer in Baghdad.
If Bush and Blair were actually concerned about the threat posed by Saddam, the decision to go to war in March, rather than waiting looks entirely unreasonable, except on the assumption that nothing could possibly go wrong. Tim Dunlop has more on this, with specific reference to Rumsfeld’s latest observation that “you go to war with the army you have”.
More generally, the precautionary principle is not, as it might seem, symmetrical. In a situation where the consequences of one option are poorly understood, it provides grounds for avoiding, or, if possible, deferring a decision to choose that option even when a naive analysis would suggest that it should produce a better outcome. War is the paradigmatic example of an activity where “the race is not always to the swift, nor the battle to the strong, but time and chance happens to them all”. All of this leads to something close to the Powell doctrine. If war is to be an instrument of policy, it should only be used under conditions of overwhelming superiority in all phases (including occupation), for clear and feasible objectives, and with a clearly formulated exit strategy.
fn1. Except where the threat is so clear and imminent that standard self-defence arguments can be invoked.
fn2. An alternative, plausible in the light of the very lackadaisical attitude to weapons exhibited after the invasion is that they knew the WMD case was bogus, and needed to start the war before it collapsed altogether.
fn3. These objectives need to be justifiable in terms of the interests of the people of the world in general, and not of the national interest of one country or the personal interests of its rulers. A nation or group that pursues self-interest through military force is an enemy to all and will ultimately attract retaliation.