The Universalizability Dilemma

The universalizability rule “tells you that if an act done by someone else is wrong (or right), it is also wrong (or right) if done by you, provided that you are in exactly the same circumstances. But, of course, you are never in exactly the same circumstances as other people, so the rule seems to be useless. To make it useful, it would have to be relaxed somewhat: If something is wrong for them, it is also wrong for you, provided your circumstances are sufficiently similar, or similar in relevant respects. But this introduces a new set of problems: When are the circumstances sufficiently similar? And when are they similar in relevant respects? What constitutes a relevant respect? Until these difficult questions are answered, the rule gives us no clear guidance.”¹