PEA Soup

A Contextualist Solution to a Puzzle about "Ought"s and "If"s

Consider the following scenario:

MINERS: 10 miners are trapped in a flooding mine; they are either all in shaft A or all in shaft B.  Given our information, each location is equally likely.   We have just enough sandbags to block one shaft, saving all the miners, if they are in the blocked shaft, but killing them all if they are in the other.  If we do nothing, the water will distribute between the two shafts, killing only the one miner positioned lowest.  On the basis of these considerations, (1) seems true:

(1)    We ought to block neither shaft.

While deliberating, though, we accept both

(2)    If the miners are in A, we ought to block A

and

(3)    If the miners are in B, we ought to block B.

We also accept

(4)    Either the miners are in A or they are in B.

And (2)-(4) seems to entail

(5)    Either we ought to block A or we ought to block B.

Paradox!

In a forthcoming paper, (“’If’s and ‘Ought’s,” JPhil), Niko Kolodny and John MacFarlane argue that the best way to resolve this paradox is to give up modus ponens.   Instead, I’ll argue, acceptance of the contextualist semantics for modal expressions I advocate (in “A Flexibly Contextualist Account of Epistemic Modals” and “A Flexible, Contextualist Account of ‘Ought’”, http://www.unl.edu/philosop/people/faculty/dowell/dowell.shtml), together with a Kratzer-style semantics for the indicative conditional, allows for a resolution of the paradox without giving up on MP.  This seems to me a clear advantage.

Flexible Contextualism about 'Ought's

Thanks to everyone for sharing their intuitions about the cases in my previous post. Here I’m going to back up and say something about my interest in the cases. Among linguists, the canonical view about modal expressions like “might”, “may” and “must” is that they are quantifiers over possibilities where the domains of quantification are contextually restricted. The view is an extremely powerful one; if correct, it provides a simple, highly unified explanation of a wide variety of language use. Recently, the canon’s neat story has come under attack on two fronts, in its treatment of bare epistemic modals (BEMs) and bare normative modals (BNMs). (A bare modal statement is a modal statement that doesn’t contain a restrictor phrase like “in view of my evidence” or “in view of what the law requires”.) I’ve got a manuscript defending a general, flexible contextualist account of bare modal statements and an application of that account to BEMs. (Here: http://www.unl.edu/philosop/people/faculty/dowell/dowell.shtml) Now I’m working on defending an application of that account to BNMs. (NB: My apologies in advance; this post is both long and oversimplified.) 

Intuitions about Bare Normative Modal Statements

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!)