On Mon, 13 Jul 1998, Joe Jenkins wrote:
> I might like to reply to your response if I only understood it. Like
> I said, I'm new to the subject of ethics and even worse its been a
> while since I read Axelrod's Evolution of Cooperation. I don't
> remember non iterated games and so I have no idea what "keep silent"
> means. Please afford me some enlightenment. Does it mean don't play
> games that are non-iterated?
Er, no. I was referring to the Prisoner's Dilemma, a classic game from the perpective of game theory and an interesting situation from the perpective of rational philosophy.
Suppose you had two prisoners about to go on trial for some atrocious crimes. Suppose neither prisoner can communicate with the other. Imagine that the prosecutor offers each a deal: they can either confess to the crime and incriminate their partner (aka "defect") or keep silent. The deal is arranged this way: if both prisoners choose to keep silent, then both will spend a short while in prision but will eventually go free. However, if one defects while the other keeps silent, then the defector may go free, but the one who keeps silent is killed. Finally, if they both defect, they both spend a life in prison.
Usually, when we think about this game in the context of of game theory, we give each of the consequences explicit payoffs; ie I get 2 points if I defect and you keep silent, I get 1 point if we both keep silent, I lose 1 point if we both defect, and I lose two pints if I keep silent while you defect. Situations like this one arguably happen fairly regularly, though the number of situations under which the payoffs are so arranged is probably overstated. However, it seems reasonable that there are a variety of situations under which you may gain at the expense of others; egoism would dictate that you do so, because it is to your best gain, no matter what the other player does. However, if both players play this strategy, both lose 1 point; (though each player would have lost more had they kept silent). On the other hand, if both players keep silent, both gain a point, yet each player could have gotten more, given the other player's choice, had they defected.
This game gets interesting when we have to play it more than once (we use the point system rather than the prison sentances, in this case.) Contests have been held to try to come up with the optimal strategy in iterated versions of the game; ie the best strategy when you must play against the same player multiple times. The undisputed winner, to the best of my knowledge, is Tit for Tat: keep silent on the first game, then do whatever your opponent did last game in further iterations. So if I'm playing against Tit for Tat, and I keep silent on the first round, Tit for Tat will keep silent on the second round. If I defect on the second round, Tit for Tat will defect on the third; etc.
The fact that Tit for Tat is the undisputed winner in terms of points seems to imply that it is the optimal strategy from the egoistic standpoint; this is contrary to our analysis above of the non-iterated version. More interesting, IMO, is the fact that it also seems to be compatible with utilitarianism, particularly when two Tit for Tats are playing against each other.
Evolutionary stability only applies to the iterated versions of the games I described above. While "Always Keep Silent" is certainly compatible with itself, if ever an "Always defect" player entered the game, it would clear out the others; it would not fare so well against Tit for Tat; while it would eek out slightly better than Tit for Tat, it would do poorly against itself, whereas Tit for Tat excels against itself. That would mean that Tit for Tat would reproduce a lot more in an evolutionary scenario, through there would always remain some equilibrium fraction of "always defect"ors in most populations. Interesting, no?
Anyway, as I said, all this means is that in most cases utilitarianism and egoism will agree on Tit for Tat. The question then becomes: what stategy should we take for the NON-iterated games, games in which you will not play against the same person again, or in which you will not know against whom you are playing? Egoism will say "always defect" in these situations; utilitarianism will say "keep silent."
If egoism is rational, then it is rational for both players; yet egoism would demand suboptimal consequences according to its own value system: the egoistic players find themselves worse off than they would have been otherwise. If we agree that rationality, at least in part, involves doing what is necessary in order to get the optimal consequences (where the "optimal" consequences is determined by one's value system) then egoism dictates that the way to fulfill the ends of egoism is to reject egoism; in other words, it is *not* rational to be an egoist, because it leaves the players worse off than it would be had they been utilitarians.