Comments on: Consequentialism for beginners

By: John Quiggin

John Quiggin — Fri, 10 Dec 2004 20:43:43 +0000

Thanks for these references, Brian, which I’ll chase. I’m also very sceptical about the Nash equilibrium concept, but I think the initial claim that rational people (in Posner’s sense) don’t engage in avoidable negative sum games is more robust than NE.

By: Brian Weatherson

Brian Weatherson — Fri, 10 Dec 2004 15:17:05 +0000

Both logically and chronologically NE (mutual best response) as a solution concept is an upshot of the economic definition of rationality, not vice versa. Although I agree I should’ve used the more general term consequence rather than response since part of game theory is about shaping the opponent’s responses, not just responding to his/her actions. I’d like to see an argument for that, because I’m pretty sure it isn’t a logical consequence. Several of the reasons for thinking that neither NE, nor any other equilibrium concept, can be derived directly from principles of individual rationality are set out in Bob Stalnaker’s recent work, e.g. * Robert Stalnaker, “Knowledge, Belief and Counterfactual Reasoning in Games”, Economics and Philosophy. 12(1): 133-163 * Robert Stalnaker, “Extensive and strategic forms: Games and models for games”, Research in Economics (1999) 53, 293–319 * Robert Stalnaker, “Belief Revision in Games: Forward and Backward Induction”, Mathematical Social Sciences, vol. 36 The one-line version is that to get from Bayesian rationality to NE (or anything like it) you need assumptions much stronger than common knowledge of mutual rationality, and those assumptions are, on the whole, wildly implausible even as idealisations. Since in war we have quite a bit less than common knowledge of mutual rationality, the relevance of NE is far from obvious.

By: fasteddie

fasteddie — Fri, 10 Dec 2004 03:25:35 +0000

Afghanistan is lose-lose only if you cling tightly to the idea that the invasion had nothing to do with 9-11, and if you believe that letting the organization which commited that war crime run the Taliban would not have led to further atrocities against Americans. Are you assuming that 9-11 was a rational act to be analyzed under this structure? Was the 9-11 attack a win for Al Qaeda? How has invading Afghanistan helped Americans? 150 dead, many many more injured. There is no security outside of Kabul. Blood and treasure gone. Opium production is up, which hurts more Americans. And Osama was not caught, which certainly leaves the US as a loser. Gathering Intelligence and capturing Osama (without blowing up a bunch of mosques) would have been a big win. But the US had other priorities. How has invading Afghanistan helped the Afghani people? Certainly the thousands killed are not better off, nor the tens of thousands injured, or related to the killed or injured. Afganistan loses also. Defintely a lose-lose. By concentrating on Iraq before Afghanistan was done, Bush & co were able to snatch defeat from the jaws of victory. Because Afghanistan has so little to destroy, even it’s loss should not have been that bad. As for 9/11, it was certainly a win for Al Quaeda, moreso because Bush/Cheney/Rumsfeld let bin Laden go, because they were drooling over Iraqi oilfields, the PNAC wet dream. The conpiracy theorist in me wants to believe this is because the elder Bush is pals with bin Laden’s family (and they’re all old chums with the Saudi royals). Osama is able to frame the conflict as “Islam under attack” and so is many steps closer to his goal of united Islam and a Caliphate.

By: Hamilton Lovecraft

Hamilton Lovecraft — Fri, 10 Dec 2004 03:11:05 +0000

Since war is a negative sum game, rational decision makers do not fight wars However, a rational decision maker of post-draftable age may encourage others to fight a war after investing heavily in military hardware manufacturing, with positive-sum result for himself.

By: ogmb

ogmb — Wed, 08 Dec 2004 23:30:17 +0000

No. That’s a definition of the Nash equilibrium concept. Both logically and chronologically NE (mutual best response) as a solution concept is an upshot of the economic definition of rationality, not vice versa. Although I agree I should’ve used the more general term consequence rather than response since part of game theory is about shaping the opponent’s responses, not just responding to his/her actions. I don’t quite follow the “acceptable criterion” point. I’m aware that simple NE is considered insufficient as a solution concept, which explains the plethora of refinements, and I realize there’s a big discrepancy between “economic rationality” and “common-sense rationality”, but I’m not sure which one you’re pointing at.

By: Bucky

Bucky — Wed, 08 Dec 2004 22:10:15 +0000

ogmb – “The problem with thinking of Iraq as a win-win war…” The problem with thinking of the “war” in Iraq as a war waged for the officially stated purpose – to unseat a dictator – is that in even the most well-intentioned and rational mind it creates an argument against something that doesn’t exist. It diverts oppositional energy into a cul-de-sac, from which it can’t emerge except in defeat. Inasmuch as your clear paragraphs emphasize the illogic and danger of what’s been done, and refute the given reasons for it, they help greatly. But it would help even more if you attacked the heart of the matter with that same clarity. The soldiers on the ground, some of them, may believe we’re there for democracy, the Christmas shoppers at the mall may believe it, but no one in Washington believes that, and very few people in the rest of the world do either. Too often an otherwise sound thinker pounces on these bogus explanations, like a dog capturing a sock, ignoring the hand that holds it for the sake of the game.

By: dsquared

dsquared — Wed, 08 Dec 2004 21:47:37 +0000

economic rationality only requires best responses to the expected actions of the other side No. That’s a definition of the Nash equilibrium concept. The further statement that Nash equilibrium is an acceptable criterion of “economic rationality” is a key controversy and game theory textbooks are wrong to pretend that it can be settled in favour of one side by a wave of the wand.

By: ogmb

ogmb — Wed, 08 Dec 2004 20:41:38 +0000

On the “can wars be win-win?” question: First of all we have recognize the fundamental shift that happened between WW1 and WW2: the treaty of Versailles to the Marshall Plan. Versailles was driven by the millenia-old rule of war, To the Victor Go the Spoils. The Marshall Plan on the other hand, rather than transferring assets from loser to winner used Allied money to invest in the defeated Axis countries. The payoff for the victors therefore moved from immediate (by seizing assets) to mediate (by creating allies and estblishing trade partnerships). Iraq, despite the claims of Halliburton profiteering, was designed as a win-win war. The people who think win-win is impossible implictly assume that the post-war economic order is the same as the pre-war order, only disrupted by loss of human lives and industrial assets. This isn’t true, and the losing side changing its political system is the historical rule rather than the exception. Falkland was a “win-win” war in that it was fairly restricted and it directly lead to the toppling of the Argentine junta, therefore giving the Argentinians at least the possibility to create a better social order than they had before. Afghanistan could have been a win-win if the GWB administration hadn’t prematurely redirected its focus to Iraq. The problem with thinking of Iraq as a win-win war is that it assumes that 1. dictatorship is the worst kind of social order, and 2. democracies just snap into place once you remove the dictator. At least domestically most dictators are preferable (and come into power as remedies) to absence of social order (aka the Libertarian Utopia), and the key rationale for keeping them in power is to keep the country from slipping into chaos. Even if there is a prospect, there are no guarantees that the post-war social order is better than the pre-war order, so fighting a (preventive) war on a win-win premise should make damn sure that the post-war order (quickly) improves on the status quo. The total blindness of the Rumsfeld-Wolfowitz-Feith fascia to this simple doctrine is the main failing of the current administration in re: Iraq.

By: Giles

Giles — Wed, 08 Dec 2004 20:41:09 +0000

“ahistorical and moralizing underlying assumption” I thought that the whole point of rational choice is that it is amoral. The point I’m making is that the plains indians with perfect foresight should have marched 1000 of miles in order to defeat the colonists in 1600 when they could. By allowing 200 years of Baysian updating of the benefits of preemptive action, err they were too late to actually take action. I’d agree with you though that the rational choice is a pretty silly way to look at whether a war can be justified.

By: mpowell

mpowell — Wed, 08 Dec 2004 20:15:33 +0000

A comment on war being a negative sum game: this only holds for the political actors involved, which is important for game theory reasons but should not extend to being a general criticism of war as some here have implied. The Afghanistan war is an excellent example of a war that has a positive sum potential when we include the wellfare of the people of Afghanistan instead of just the interests of the Taliban ruling them. In the case where a regime is not representing the interests of those being ruled, there is always the possibility of a positive sum when that rulership is changed, be it through internal revolution or war against an external foe. If such a war were never desirable, then revolution against an unjust government would also have to be always undesirable.

By: Thomas

Thomas — Wed, 08 Dec 2004 19:58:19 +0000

DD—It may be true that preventive wars have a worse record than other kinds of wars, and certainly that is relevant, if true, to those deciding on whether to wage preventive war. The goal is to wage only those preventive wars worth waging (however calculated), and we aren’t helped any if we’re told to avoid all preventive wars because most turn out to be not worth waging. The trick is to identify which ones are and which ones aren’t.

By: ogmb

ogmb — Wed, 08 Dec 2004 19:48:03 +0000

Dsquared: since wars by definition involve the diversion of productive resources into producing expensive pieces of capital equipment which are delivered to people who don’t want them and then explode, they can’t be positive or zero-sum events. Any war is Pareto dominated by a contract under which both parties agree to the outcome that the war would have produced without fighting. Pareto dominatedness doesn’t equal irrationality, and negative sum in accounting terms doesn’t mean it’s a negative sum game. You’re also assuming enforcible contracts and a “good” peacetime allocation of resources, neither of which are givens in international relations. But I get the point about war being mutual destruction of resources, therefore a “negative” event. But this doesn’t imply irrationality. Either side, in order to prevent war, would be willing to pay R-P (the delta between peacetime and wartime payoffs) to the other side each round, but on the other hand also faces the prospect getting up to R-P from the other side, so there’s a lot of money on the table to fight over. A decision for war can be rational if discounted expected postwar payoff minus discounted war payoff exceeds discounted payoffs without a war. Since by assumption P < R this requires that both sides’ expected probabilities of winning sum up to more than one—iow, overconfidence. But overconfidence is not necessarily irrational because economic rationality only requires best responses to the expected actions of the other side.

By: roger

roger — Wed, 08 Dec 2004 19:27:19 +0000

There seems to be an odd current in this discussion of war, in which wars are over issues—not territory. It is as if we really went to war to bring Iraq democracy. That is, I think, a laughable proposition. Most wars are over territory. Hence, the cost of diverting productive resources for, say, the British in 1765, fighting against the French, could be recouped by the seizure of territories—for instance, islands dominated by the sugar cane industry—that would pay back the cost of the war. Plus block competition from another power. That twentieth century wars are justified in terms of ideology—creating the socialist brotherhood of man, helping the Aryan race achieve its natural dominance, building democracy in the Middle East, etc.—doesn’t really make a difference. In the past, wars could be justified by converting the heathen. But it was best when the converted heathen then went down into the silver mines and brought up what you’d conquered the territory for in the first place. The result, of course, has to be judged not just in terms of winning, but also the benefit the victor accrues from winning. Say that the pre-emptive war with Iraq went as planned, as it still might, and the American oil corporations were able to purchase, at rock bottom prices, rights to petroleum production that, given the current state of oil exploration, are going to be increasing in value. Or even that America secures its oil routes, and has a reserve country to fall back upon if, say, the Saudis have trouble. Pre-emption, then, is a perfect strategy for aggression. As it has been in the past—the U.S. is disinclined to ask itself why it is the most aggressive power on the globe, and has been for some sixty years. It has a pattern of always defending itself by invading other countries—hell, the symbol is that the Department of War is called the Department of Defense. These aggressions, in the nineteenth century, were similarly marked as pre-emptive wars—the acquisition, for instance, of the American Southwest and California was such a pre-emptive war, with Polk simply defending American territory from the presumend continued aggressions of the Mexican army. The recent invasion of Panama, on the other hand, was a war for “democracy”, resulting in the replacement of an American puppet gone bad, Noriega, with a series of farcical oligarchs—but those oligarchs were all pliable to America’s economic interest. The attempt to overthrow Chavez in Venezuala by a coup was clearly anti-democratic, but motivated by oil. And so on. To do the calculus correctly, then, you need to include two factors: 1. consider the war not in isolation, but as part of series of wars—since the U.S. has engaged in some two hundred various sized interventions in the past fifty years, the calculus would certainly have to include advantages with regard to the next war the Americans engage in; and 2, territorial acquisition, or some equivalent in terms of economic benefit. You have a different set of markers to adjudge the war’s rationality if you through in these considerations.

By: Walt Pohl

Walt Pohl — Wed, 08 Dec 2004 18:21:59 +0000

Before we go completely off-track here: neither Afghanistan nor Gulf War I were preventative wars.

By: abb1

abb1 — Wed, 08 Dec 2004 17:43:56 +0000