Another way of viewing this would be that my preferences run thus: (D,C);(C,C);(C,D);(D,D) and Clippy run like this: (C,D);(C,C);(D,C);(D,D).
Wait, what? You prefer (C,D) to (D,D)? As in, you prefer the outcome in which you cooperate and Clippy defects to the one in which you both defect? That doesn’t sound right.
woops, yes that was rather stupid of me. Should be fixed now, my most preferred is me backstabbing Clippy, my least preferred is him backstabbing me. In the middle I prefer cooperation to defection. That doesn’t change my point that since we both have that preference list (with the asymmetrical ones reversed) then it’s impossible to get either asymmetrical option and hence (C,C) and (D,D) are the only options remaining. Hence you should co-operate if you are faced with a truly rational opponent.
I’m not sure whether this holds if your opponent is very rational, but not completely. Or if that notion actually makes sense.
Wait, what? You prefer (C,D) to (D,D)? As in, you prefer the outcome in which you cooperate and Clippy defects to the one in which you both defect? That doesn’t sound right.
woops, yes that was rather stupid of me. Should be fixed now, my most preferred is me backstabbing Clippy, my least preferred is him backstabbing me. In the middle I prefer cooperation to defection. That doesn’t change my point that since we both have that preference list (with the asymmetrical ones reversed) then it’s impossible to get either asymmetrical option and hence (C,C) and (D,D) are the only options remaining. Hence you should co-operate if you are faced with a truly rational opponent.
I’m not sure whether this holds if your opponent is very rational, but not completely. Or if that notion actually makes sense.