To help someone, you don’t need him to have an utility function, just preferences. Those preferences do have to have some internal consistency. But the consistency criteria you need to in order to help someone seem strictly weaker than the ones needed to establish an utility function. Among the von Neumann-Morgenstern axioms, maybe only completeness and transitivity are needed.
For example, suppose I know someone who currently faces choices A and B, and I know that if I also offer him choice C, his preferences will remain complete and transitive. Then I’d be helping him, or at least not hurting him, if I offered him choice C, without knowing anything else about his beliefs or values.
Or did you have some other notion of “help” in mind?
To help someone, you don’t need him to have an utility function, just preferences. Those preferences do have to have some internal consistency. But the consistency criteria you need to in order to help someone seem strictly weaker than the ones needed to establish an utility function. Among the von Neumann-Morgenstern axioms, maybe only completeness and transitivity are needed.
For example, suppose I know someone who currently faces choices A and B, and I know that if I also offer him choice C, his preferences will remain complete and transitive. Then I’d be helping him, or at least not hurting him, if I offered him choice C, without knowing anything else about his beliefs or values.
Or did you have some other notion of “help” in mind?