Right now I’m thinking about the proper descriptive semantics for bare, normative modal statements, statements that use expressions like “must”, “ought”, and “may” normatively but don’t contain explicit restrictor phrases like “legally”, “morally”, or “given what I know”. I’m developing my own account of their semantics and my plan is to discuss the issues raised in at least two separate posts. Right now I’d just like to hear other people’s intuitions about possible assertions in different cases. Since the ideal would be responses unpolluted by theory, I want first to present the two cases that now most interest me and just elicit reactions, holding off my own theory of these uses for a second post. (Some of you may recognize these cases as similar to others that arise in discussions in linguistics and philosophy of language, others in the ethics literature. I’m hoping that in your comments, you just address the question of your intuitions, holding off your comments on the theoretical issues raised until my second post, since I’m hoping that the comments also won’t pollute the reactions of later commentators. I’m also hoping yours aren’t polluted by knowledge of others’ reactions, so please post your own before reading the earlier comments. Sorry to be so fussy!)
Here’s the first case:
You’re sitting in an audience of people who (including yourself) have some medical knowledge. You’re watching a dramatic reenactment of a discussion between two doctors of a decades-old medical case. The two doctors are called "Doctor" and "Consultant". Doctor is deciding which of three drugs X, Y, or Z to prescribe to his patient to relieve the symptoms of a skin ailment. Here's what Doctor's evidence suggests about each of the three drugs: Each of drugs X and Y have the potential to provide complete relief for Patient, while drug Z can only provide partial relief. In light of that, Doctor asserts "I ought to prescribe either X or Y". Consultant, however, knows more about each of the drugs than Doctor does. In particular, she knows that Patient is already taking drug W and that exactly one of X or Y is lethal in combination with drug W. Each has an equal likelihood of being the cure and of being the lethal drug. She also knows that Z has no negative side effects and does not interact adversely with W.
In light of this, Consultant says
(Z) "No, you ought not prescribe either X or Y; you ought to prescribe Z."
And Doctor replies
(Z’) "You're right; I ought to prescribe Z."
So, here you are, watching this reenactment decades after the fact. You and your other audience members now know what neither Doctor nor Consultant could have known then, which is that X is the drug that will kill a patient in combination with W. Drug Y will effect a complete cure, even when taken with W and will have no adverse reactions.
Q: which of the following would it be ok for you or someone else to say in reaction to (Z) and (Z’)? Which, if any of the following are not ok (sound bad or weird)? If some of the ok possible assertions are less ok than others, how would you rank them? Ditto for bad and worse.
(Dp) “I disagree. Doctor ought to have prescribed Y.”
(Fp) “That’s false. Doctor ought to have prescribed Y.”
(Gp) “That’s a shame. Doctor ought to have prescribed Y.”
(Sp) “That’s a shame. It’s too bad Doctor didn’t know that Y would have completely cured Patient. But she did the right thing; she ought to have prescribed Z.”
Consider now a similar case, but one that doesn’t involve a time delay. Imagine that Doctor had planned to teleconference with Consultant II about the case. Consultant II knows that X, but not Y, interacts lethally with W. Just after Consultant has provided the information about Patient’s use of W, but before Consultant II can speak, Consultant II’s electronics give out. He can now see and hear the exchange between Doctor and Consultant, but can’t communicate with them. He overhears Consultant assert (Z) and Doctor assert (Z’).
How might Consultant II appropriately react? Here again are some options:
(Dn) “I disagree. Doctor ought to prescribe Y.”
(Fn) “That’s false. Doctor ought to prescribe Y.”
(Gn) “That’s a shame. Doctor ought to prescribe Y.”
(Sn) “That’s a shame. It’s too bad Doctor doesn’t know that Y would completely cure Patient. But she’s doing the right thing; she ought to prescribe Z.”