Philosophers are sometimes caricatured for offering unhelpful answers to difficult questions. For example, if asked, “What ought I to do?”, we philosophers might say, “Do what matters most!” This answer seems problematic because it exchanges the original question for another — what matters most? — that is at least as challenging. Another thing that philosophers get caricatured for is teasing out the consequences of highly unlikely circumstances. Readers of this review will be all-too-familiar with imaginary brains-in-vats and runaway trolleys to need much of a reminder.
But what would happen if we embraced both of these caricatures? Suppose for one happy moment that we discovered what matters most and that we should do whatever most matters. Would that be enough to tell us what we ought to do? If so, we would not need Douglas W. Portmore’s elegant, thoroughgoing, and painstakingly reasoned book. This project, based on a handful of previously published articles, is an attempt to articulate and resolve many of the thorny issues about what we ought to do that remain after we determine — if we ever do — what matters most. You should prioritize careful study of this book, if you are interested in obligation, moral responsibility, the philosophy of action, supererogation, suberogation, and outcomes that are either overdetermined or underdetermined, as well as outcomes that involve misdeeds in the future.
— Read on ndpr.nd.edu/news/opting-for-the-best-oughts-and-options/