In practice, everyone's motivation is a mixture of all sorts of stuff, and very little is even a utility function...

But in theory, this is how I would define a selfish utility: one that is defined entirely in terms of an index "me". If you have two people with exactly the same selfish utility function, completely identical (except that the "me" is different), then those two utilities are independent of each other.

Comment author:gjm
06 September 2017 09:00:21AM
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Probably the only actual human beings whose utility functions (in so far as they have them) are perfectly selfish are sociopaths, or very odd psychologically in other ways. But considering hypothetical agents with perfectly selfish utility functions is mostly just a convenient approximation. (And it's not that bad an approximation; most people are very well approximated, in many of their interactions, as perfectly selfish agents, and the approximation errs more badly by assuming that they have utility functions than by assuming that they're perfectly selfish. I think.)

The problem with selfish utility, is that even selfish agents are assumed to care about themselves at different moments in time. In a world where copying happens, this is under defined, so selfish has multiple possible definitions.

## Comments (34)

BestIn practice, everyone's motivation is a mixture of all sorts of stuff, and very little is even a utility function...

But in theory, this is how I would define a selfish utility: one that is defined entirely in terms of an index "me". If you have two people with exactly the same selfish utility function, completely identical (except that the "me" is different), then those two utilities are independent of each other.

Would it be correct to define selfish utility as sociopathic?

Probably the only actual human beings whose utility functions (in so far as they have them) are perfectly selfish are sociopaths, or very odd psychologically in other ways. But considering hypothetical agents with perfectly selfish utility functions is mostly just a convenient approximation. (And it's not

that badan approximation; most people are very well approximated, in many of their interactions, as perfectly selfish agents, and the approximation errs more badly by assuming that they have utility functions than by assuming that they're perfectly selfish. I think.)*0 points [-]The problem with selfish utility, is that even selfish agents are assumed to care about themselves at different moments in time. In a world where copying happens, this is under defined, so selfish has multiple possible definitions.

Depends on your definition of sociopathy. Not under DSM.