Why couldn't two identical AIXI-type agents recognize one another to some extent? Stick a camera on the agents, put them in front of mirrors and have them wiggle their actuators, make a smiley face light up whenever they get rewarded. Then put them in a room with each other.
If you're suggesting this as a way around AIXI's immortality delusion, I don't think it works. AIXI "A" doesn't learn of death even if it witnesses the destruction of its twin, "B", because the destruction of B does not cause A's input stream to terminate. It's ... (read more)
Let me try to strengthen my objection.
Put multiple AIXItI's in a room together, and give them some sort of input jack to observe each other's observation/reward sequences. Similarly equip them with cameras and mirrors so that they can see themselves. Maybe it'll take years, but it seems plausible to me that after enough time, one of them could develop a world-model that contains it as an embodied agent.
I.e. it's plausible to me that an AIXItI under those circumstances would think: "the turing machines with smallest complexity which generate BOTH my observations of those things over there that walk like me and talk like me AND my own observations and rewards, are the ones that compute me in the same way that they compute those things over there".
After which point, drop an anvil on one of the machines, let the others plug into it and read a garbage observation/reward sequence. AIXItI thinks, "If I'm computed in the same way that those other machines are computed, and an anvil causes garbage observation and reward, I'd better stay away from anvils".
If you're suggesting this as a way around AIXI's immortality delusion, I don't think it works. AIXI "A" doesn't learn of death even if it witnesses the destruction of its twin, "B", because the destruction of B does not cause A's input stream to terminate. It's ... (read more)