Kant's deontology and game theory.

(from ssc) You're a prisoner of war. Your side is good. Your captors, the enemy, are evil. Your captors ask you to tell them where you country's to general is hiding. If you do, they'll kill him with a precision airstrike. If you don't, they'll nuke the whole city, killing everyone including the general. That's worse for them and worse for your side. Option 3, lie about your generals location. They bomb the wrong place, your general, knowing they're after him, escapes to a bunker and you win the war.

Strict deontology says lying is bad and so you should tell the truth. Objection 1: if sometimes a lie can do a great deal of good it is hence justified, the lesser of two evils. The problem if that if people generally lie when it suits them, lies become expected and no longer work. On top of that, as trust becomes more difficult people cannot offer positive sum tradeoffs if defection is possible. If POWs regularly like, then your enemy has no choice but to nuke the whole city.

All of this is what have read elsewhere. Now for my own.

The problem with Kant is best understood from a game theoretic perspective. Imagine a prisoners dilemma. Cooperation is good. Defection is better for the defector, but worse for the other player and both players added together (lower net utility). Mutual betrayal has the lowest net utility but higher individual utility than being the sucker who gets defected on. Cooperation is good, but the individually rational decision (assuming agents whose overriding goal is maximising their own payoffs) is to defect.

A similar problem occurs with Kantian deontology. Lying is good for you. Not only that, but the more honest most people are, the more you stand to gain from lying. So in a Kantian world defection is super awesome (for you). How then would such a world work? Sure Kant is right that a society where no one lies ever is better than one where lying is not uncommon, but the problem is that

1. a society where most people do not lie but only some do may be even worse than either
2. This cannot be a stable equilibrium as defection becomes so rewarding

Replace "lying" with "being moral" and you see part of a problem with Kant.

Hersey: this is one of the more retarded articles I've written. A few select idiocies:

• Less lying does not make lying easier or more rewarding. The issue may well be true.  Ditto for morality.
• People are not utility maximising machines. The more people act in a war, the stronger the norm. Resisting the urge to lure is easy when you are raised in a society where lying is a sin just add dying is easy when you are raised in a warrior culture.