Shelly Kagan

Many proposed moral principles are such that it would be difficult or impossible to always correctly identify which act is required by that principle in a given situation. To deal with this problem, theorists typically offer various methods of determining what to do in the face of epistemic limitations, and we are then told that the right thing to do – given these limitations – is to perform the act identified by the given method. But since the method and the underlying principle can diverge, it would seem that in such cases we are being given contradictory advice: some particular act will be both right and not right. Various attempts to resolve this apparent paradox are surveyed, but none are completely satisfactory.

Anyone who reflects on the way we go about arguing for or against moral claims is likely to be struck by the central importance we give to thinking about cases. Intuitive reactions to cases—real or imagined—are carefully noted, and then appealed to as providing reason to accept various claims. When trying on a general moral theory for size, for example, we typically get a feel for its overall plausibility by considering its implications in a range of cases. Similarly, when we try to refine the statement of a principle meant to cover a fairly specific part of morality, we guide ourselves by testing the various possible revisions against a carefully constructed set of cases. And when arguing against a claim, we take ourselves to have shown something significant if we can find an intuitively compelling counterexample, and such counterexamples almost always take the form of a description of one or another case where the implications of the claim in question seem implausible. Even when we find ourselves faced with a case where we have no immediate and clear reaction, or where we have such a reaction, but others don't share it and we need to persuade them, in what is probably the most common way of trying to make progress we consider various analogies and disanalogies; that is to say, we appeal to still other cases, and by seeing what we want to say there, we discover what it is plausible to say in the original case. In these and other ways, then, the appeal to cases plays a central and ubiquitous role in our moral thinking