Blackburn argues that this kind of over-demandingness threatens to undermine ethics itself. “The center of ethics must be occupied by things we can reasonably demand of each other,” he writes. Our duty to help others cannot be infinite. The moral principles we adopt must not reduce us to slaves of the impersonal good. It may be praiseworthy to give away all your money in order to save starving children abroad, or to quit your Park Avenue medical practice and join Doctors Without Borders, or to invite the homeless to crash in your apartment, but it is not obligatory.
