I believe that it is possible for two agents to have the exact same source code while (in some sense) optimising two different utility functions.
I take a utility function to be a function from possible world states to real numbers. When I say that an agent is optimising a utility function I mean something like that the agent is "pushing" its environment towards states with higher values according to said utility function. This concept is not entirely unambiguous, but I don't think its necessary to try to make it more explicit here. By source code I mean the same thing as everyone else means by source code.
Now, consider an agent which has a goal like "gain resources" (in some intuitive sense). Say that two copies of this agent are placed in a shared environment. These agents will now push the environment towards different states, and are therefore (under the definition I gave above) optimising different utility functions.
The core feature here seems to be that the agent has some ability to refer to itself, and that this localization differs between instantiations. Alice optimizes for dollars in her wallet, Bob optimizes for dollars in his wallet, and so they end up fighting over dollars despite being clones, because the cloning procedure doesn't result in arrows pointing at the same wallet.
It seems sensible to me to refer to this as the 'exact same source code,' but it's not obvious to me how you would create these sort of conflicts without that sort of different resolution of pointers, and so it's not clear how far this argument can be extended.
You don't necessarily need "explicit self-reference". The difference in utility functions can also be obtained due to a difference in the location of the agent in the universe. Two identical worms placed in different locations will have different utility functions due to their atoms being not exactly in the same location, despite not having explicit self-reference. Similarly, in a computer simulation, the agents with the same source code will be called by the universe-program in different contexts (if they weren't, I don't see how ... (read more)