A lot of people seem to think that ethics is subjective. This does make some sense; what each of us feels is morally right in any given situation often differs, so I can see how it might be tempting to conclude that ethics has no right answers,
* Douglas, H. (2004). The Irreducible Complexity of Objectivity. Synthese (Dordrecht), 138(3), 453–473. https://doi.org/10.1023/B:SYNT.0000016451.18182.91
Take, for example, the following argument:
I'm sitting in a room typing this right now. If I wanted to leave this room and move into the hallway outside, I would be objectively more likely to succeed if I were to walk through the room's doorway rather than trying to walk through one of the walls. Regardless of how proficient I believe myself to be in the art of walking through walls, no amount of will or belief on my part is going to change the reality that I can't walk through walls. Therefore, if I wished to achieve a desired goal of making it out of this room, I should walk through the doorway.