Why do people seem to mean different things by “I want the pie” and “It is right that I should get the pie”?
I think the meaning of “it is (morally) right” may be easiest to explain through game theory. Humans in the EEA had plenty of chances for positive-sum interactions, but consistently helping other people runs the risk of being exploited by defection-prone agents. Accordingly, humans may have evolved a set of adaptions to exploit non-zero sumness between cooperating agents, but also avoid cooperating with defectors. Treating “X is (morally) right” as a warning of the form “If you don’t do X, I will classify that as defection” explains a lot.
Assume a person A has just (honestly) warned a person B that “X is the right thing to do”:
If B continues not do X, A will likely be indignant; indignancy means A will be less likely to help B in the future (which makes sense according to game theory), and might also recommend the same to other members of the tribe.
B might accept the claim about rightness; this will make it more likely for him to do the “right” thing. Since, in the EEA, being ostracized by the tribe would result in a significant hit to fitness, it’s likely for there to be an adaption predisposing people to evaluate claims about rightness in this manner.
B’s short-term desires might override his sense of “moral rightness”, leading to him doing the (in his own conception) “wrong” thing.
While B can choose to do the wrong thing, he cannot change which action is right by a simple individual decision, since the whole point of evaluating rightness at all is to evaluate it the same way as other people you interact with.
According to this view, moral duties function as rules which help members of a society to identify defectors (by defectors violating them).
Regarding the first question,
I think the meaning of “it is (morally) right” may be easiest to explain through game theory. Humans in the EEA had plenty of chances for positive-sum interactions, but consistently helping other people runs the risk of being exploited by defection-prone agents. Accordingly, humans may have evolved a set of adaptions to exploit non-zero sumness between cooperating agents, but also avoid cooperating with defectors. Treating “X is (morally) right” as a warning of the form “If you don’t do X, I will classify that as defection” explains a lot. Assume a person A has just (honestly) warned a person B that “X is the right thing to do”:If B continues not do X, A will likely be indignant; indignancy means A will be less likely to help B in the future (which makes sense according to game theory), and might also recommend the same to other members of the tribe. B might accept the claim about rightness; this will make it more likely for him to do the “right” thing. Since, in the EEA, being ostracized by the tribe would result in a significant hit to fitness, it’s likely for there to be an adaption predisposing people to evaluate claims about rightness in this manner. B’s short-term desires might override his sense of “moral rightness”, leading to him doing the (in his own conception) “wrong” thing. While B can choose to do the wrong thing, he cannot change which action is right by a simple individual decision, since the whole point of evaluating rightness at all is to evaluate it the same way as other people you interact with.
According to this view, moral duties function as rules which help members of a society to identify defectors (by defectors violating them).