But as we move forward into modernity, intellectual types lose their faith [in heaven and hell]. But there's still a desire to come up with a moral system that people will want to follow. Hence we start hearing complaints that normative view X or Y is "too challenging" because morality, apparently, is supposed to be easy and it's just not cool for Peter Singer (and others) to go around telling us that it might suck to do the right thing.The implication is that there’s something facile or illegitimate about criticizing a moral philosophy for being “too challenging.” But even if the difficulty of following moral dictates is not the only relevant factor, surely it’s at least one relevant factor.
I take it as given that the purpose of a moral system is to guide the behavior of actual people. People are not angels; they cannot be expected to follow moral rules purely because they have (allegedly) been justified by religious or philosophical reasoning. Nor are they devils; they will sometimes set aside personal gain for moral reasons. In the real-world middle ground between angels and devils, whether people follow moral rules depends on the persuasiveness of the rules’ justifications, how fully people have been socialized to respect the rules, the degree of temptation they face to break the rules, and the degree of difficulty involved in following the rules. Given the last two factors, it follows that some moral systems may fail to guide the behavior of actual people – or more importantly, fail to guide their behavior in the intended manner – because the rules ask too much. To be more specific, the rules may ask too much incentive-wise, by demanding that people sacrifice too much; and they may ask too much information-wise, by requiring costly or inaccessible knowledge for their concrete application. (Mario Rizzo refers to the latter issue as “the knowledge problem of ethics,” which is analogous to Hayek’s famed knowledge problem of economics.)
Now for the crucial Spider-Man application. When Peter Parker begins to think that being Spider-Man entails giving up everything good in his life (romance, career success, etc.), he starts to become despondent. The physical manifestation of his depression is the temporary loss of his super powers. In short, the excessive moral demands of being a selfless superhero make him less effective as a hero. His powers only return when those he loves most – Aunt Mae and Mary Jane – are directly threatened by Dr. Octopus, and the return of his powers enables him to save the day. The activation of his own loves and desires brings out the best in him. The moral of the first movie, in the words of Uncle Ben, was that with great power comes great responsibility. But I think the moral of the second movie could easily be: if the burden of responsibility becomes too great, it becomes self-defeating.
(See also the comments from Henry Farrell and Brayden King, and Yglesias's favorable response.)