Nope, in the end it all comes down to your personal self-conception and intuition. You can back it up with calculations and testing your emotional reaction to intellectual counterfactuals (“how does it feel that I saved half a statistical life, but couldn’t support my friend this month”). But all the moral arguments I’ve seen come down to either religious authority or assertion that some intuitions are (or should be) universal.
Nope, in the end it all comes down to your personal self-conception and intuition. You can back it up with calculations and testing your emotional reaction to intellectual counterfactuals (“how does it feel that I saved half a statistical life, but couldn’t support my friend this month”). But all the moral arguments I’ve seen come down to either religious authority or assertion that some intuitions are (or should be) universal.