Zachary: One would have to be blind to the reality of moral obligation to deny that people who believe a course of action to be morally obligatory for them have both the right and the duty to pursue that action, and that no one else has any right to stop them from doing so. Cynthia: But imagine an artist who feels morally obliged to do whatever she can to prevent works of art from being destroyed confronting a morally committed antipornography demonstrator engaged in destroying artworks he deems pornographic. According to your principle that artist has, simultaneously, both the right and the duty to stop the destruction and no right whatsoever to stop it. Cynthia's response to Zachary's claim is structured to demonstrate that ["Zachary's principle is untenable on its own terms", "Zachary's principle is based on an understanding of moral obligation that is too narrow to encompass the kind of moral obligation artists feel toward works of art", 'because the term "moral obligation" is understood differently by different people, it is impossible to find a principle concerning moral rights and duties that applies to everyone', 'the concept of moral obligation is incoherent']