The ECB and the Davies Folk Theorem

by Henry on November 18, 2011

“Mario Draghi”:http://www.ecb.europa.eu/press/key/date/2011/html/sp111118.en.html

bq. Let me use this occasion to dwell a bit further on monetary policy in the current environment. Three principles are of the essence: continuity, consistency and credibility. Continuity first and foremost refers to our primary objective of maintaining price stability over the medium term. Consistency means to act in line with our primary objective and with our strategy both in time and over time. Credibility implies that our monetary policy is successful in anchoring inflation expectations over the medium and longer term. This is the major contribution we can make in support of sustainable growth, employment creation and financial stability. And we are making this contribution in full independence. Gaining credibility is a long and laborious process. Maintaining it is a permanent challenge. But losing credibility can happen quickly – and history shows that regaining it has huge economic and social costs.

“Daniel Davies”:https://crookedtimber.org/2006/11/29/reputations-are-made-of/ (on the Iraq War, but trust me – the logic travels).

bq. At this late stage in the occupation of Iraq, many of Henry Kissinger’s old arguments about Indo-China are being dusted down. One of the hoariest and worst is that we need to “stay the course” (or some similar euphemism) in order to maintain “credibility” – to demonstrate our resolve to our enemies, who will otherwise continue to attack us. It reminds me of my one and only contribution to the corpus of game theory.

bq. The Folk Theorem in game theory states that any outcome of a repeated game can be sustained as an equilibrium if the minimax condition for both players is satisfied. In plain language, it can be summarised as stating that “if we take strategic considerations into account, there is a game-theoretic rationale for practically anything”. This formulation leads on to my contribution, the Davies-Folk Theorem, which states that “if we take strategic considerations into account,there is a game-theoretic rationale for practically fucking anything” (it’s a fairly simple corollary; proof available from author on request).

bq. The point being that since game theory in general provides the analyst with so many opportunities to twist himself repeatedly up his own arse like a berserk Klein bottle, if a given real-world course of action appears to have nothing going for it other than a game-theoretic or strategic justification, it’s almost certainly a bad idea. Thus it is with that bastard child of deterrence, “credibility”.

bq. … The idea is that the war is costing huge amounts of money and lives with no real prospect of success and a distinct danger that it is making things much worse. However, to do the logical thing would send the signal to our enemies that we will give up if fought to a pointless bloody standstill. Therefore, for strategic reasons, we must redouble our efforts, in order to send the signal to our enemies that we will fight implacably and mindlessly in any battle we happen to get into, forever, in order to dissuade them from attacking us in the first place. It’s got the kind of combination of “counter-intuitive” thinking and political convenience that always appeals to the armchair Machiavelli, as well as to the kind of person who thinks it’s witty to describe things as “Economics 101” (Airmiles has been all over this one for ages, naturally). What’s it like as a piece of game-theoretic reasoning?

bq. Lousy. It is certainly true that one of the benefits of doing something stupid is that it saves you from having to spend money on maintaining your reputation as an idiot. However, is the reputation of an idiot really worth having?

bq. It turns out that it can be proved by theorem that the answer is no. If the game of being a belligerent idiot with no sensible regard for one’s own welfare _was_ worth the candle, in the sense of conferring benefits which outweighed the cost of gaining it, then everyone would want to get that reputation, whether they were genuinely an idiot or not. But if everyone wanted that reputation, then everyone would know that simply acting like an idiot didn’t mean that you were one, in which case it would be impossible to establish a reputation as an idiot in the first place. The point here is that it’s one of the more important things in game theory that a signal has to be a _costly_ signal to be credible; like membership of the Modern Languages Association, a reputation in deterrence theory is something that is worth having, but not worth _getting._ People who use the word “signal” in this context (usually on the basis of a poorly understood or second-hand reading of Schelling) don’t always seem to realise that they are explicitly admitting that the costs of being in Iraq are greater than the benefits.

This “story”:http://www.irishtimes.com/newspaper/frontpage/2011/1118/1224307767242.html highlights the political awkwardness of the current European political dispensation. The German Bundestag’s Finance Committee apparently knows more about the Irish government’s economic plans than the Irish public or, indeed, the Irish parliament. Nor is it very good at keeping the information to itself.

bq. THE GOVERNMENT has complained to the European Commission over the release in Germany of a document disclosing confidential details about new taxes to be introduced in Ireland over the next two years. In a deeply embarrassing development the document – identifying austerity measures of €3.8 billion in next month’s budget and €3.5 billion in budget 2013 – was made public after being shown to the finance committee of the German Bundestag yesterday. … Germany’s federal finance ministry confirmed yesterday that it had forwarded troika documents to the 41 member Bundestag budgetary committee in line with its legal obligation under European Financial Stability Facility guidelines. … Taoiseach Enda Kenny said last night he had “no idea” how details of the forthcoming budget ended up being discussed in the Bundestag in Germany. “Let me confirm something to you, the Cabinet has made no decision in regard to the budget which is on December 6th,” he said, referring to the documents [sic] specific references to the budget.

Herr Kauder’s “unfortunate turn of phrase”:http://www.ft.com/intl/cms/s/0/25ef197c-0f90-11e1-88cc-00144feabdc0.html#axzz1dqCgSwXl aside, this is not a sustainable political equilibrium, either for Germany or for the states on the receiving end of EU-crafted austerity policies. The politics of the bailout are embroiling the national politics of different European member states in ways that are likely to increase distrust and unhappiness in all of them. Nor is this going to get better without major institutional reforms at the EU level (assuming, of course, that the EU survives long enough to institute such reforms).

Skeptics of the need for ‘more Europe’ and in particular ‘more democratic Europe,’ have some excellent arguments. It’s extremely difficult to map out the political processes through which this could happen. But the ever-more-labyrinthine entwinement of different countries’ national economic politics with each other will be increasingly unbearable without some such changes. A Europe in which Germany is both the paymaster and the taskmaster is not going to be a happy Europe, either for Germany itself or for the countries entangled with it.