What's wrong with "I will cooperate with anyone who verifiably asserts that they cooperate with me".

The word "me". By Rice's theorem, they can't tell that they're dealing with someone computationally equivalent to me, and there's no other sense of my "identity" that can be referred to.

Athough that could be added. Have all competitors choose a unique name and allow them to verifiably claim to be the owner of their name. Then "I will cooperate with anyone who verifiably asserts that they cooperate with me" can work ... (read more)

Your source code is your name. Having an additional name would be irrelevant. It is certainly possible for bots to prove they cooperate with a given bot, by looking at that particular bot's source. It would, as you say, be much harder for a bot to prove it cooperates with every bot equivalent to a given bot (in the sense of making the same cooperate/defect decisions vs. every opponent).

Rice's theorem may not be as much of an obstruction as you seem to indicate. For example, Rice's theorem doesn't prohibit a bot which proves that it defects against all defe... (read more)

Prisoner's dilemma tournament results

by AlexMennen 1 min read9th Jul 2013124 comments


The prisoner's dilemma tournament is over. There were a total of 21 entries. The winner is Margaret Sy, with a total of 39 points. 2nd and 3rd place go to rpglover64 and THE BLACK KNIGHT, with scores of 38 and 36 points respectively. There were some fairly intricate strategies in the tournament, but all three of these top scorers submitted programs that completely ignored the source code of the other player and acted randomly, with the winner having a bias towards defecting.

You can download a chart describing the outcomes here, and the source codes for the entries can be downloaded here.

I represented each submission with a single letter while running the tournament. Here is a directory of the entries, along with their scores: (some people gave me a term to refer to the player by, while others gave me a term to refer to the program. I went with whatever they gave me, and if they gave me both, I put the player first and then the program)

A: rpglover64 (38)
B: Watson Ladd (27)
D: skepsci (24)
E: Devin Bayer (30)
F: Billy, Mimic-- (27)
G: itaibn (34)
H: CooperateBot (24)
I: Sean Nolan (28)
J: oaz (26)
K: selbram (34)
L: Alexei (25)
M: LEmma (25)
N: BloodyShrimp (34)
O: caa (32)
P: nshepperd (25)
Q: Margaret Sy (39)
R: So8res, NateBot (33)
S: Quinn (33)
T: HonoreDB (23)
U: SlappedTogetherAtTheLastMinuteBot (20)