JOBNAME: No Job Name PAGE: 1 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 8397CB03 /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
Toppan Best-set Premedia Limitedbs_bs_query Journal Code: PAPQ Proofreader: Mony Article No: PAPQ12048 Delivery date: 29 Sep 2014 Page Extent: 29
1bs_bs_query
2bs_bs_query
3bs_bs_query THE IF P, OUGHT P
4bs_bs_query
5bs_bs_query 1 PROBLEM bs_bs_query
6bs_bs_query
7bs_bs_query BY
8bs_bs_query
9bs_bs_query JENNIFER CARR
10bs_bs_query
11 bs_bs_query
12bs_bs_query Abstract: Kratzer semantics for modals and conditionals generates the predic-
13bs_bs_query tion that sentences of the form if p, ought p are trivially true. As Frank and
14bs_bs_query Zvolenszky show, for certain flavors of modality, like deontic modality, this
15bs_bs_query prediction is false. I explain some conservative solutions to the problem, and
16bs_bs_query then argue that they are inadequate to account for puzzle cases involving
17bs_bs_query self-frustrating oughts. These cases illustrate a general problem: there are two
18bs_bs_query forms of information-sensitivity in deontic modals. Even generalizations of
19bs_bs_query Kratzer semantics that predict these two roles for information, e.g. Kolodny
20bs_bs_query and MacFarlane predict that they vary together. I propose a generalization of
21bs_bs_query Kratzer semantics that allows the two information roles to vary independently
22bs_bs_query of each other. 2 bs_bs_query
23bs_bs_query
24bs_bs_query Introductory modal logic told us that modals quantify over possible
25bs_bs_query worlds: ought p is true iff p is true at all worlds within in a specified domain.
26bs_bs_query And the popular restrictor analysis of conditionals told us that condition-
27bs_bs_query als are a kind of modal: if p, q is true iff q is true at a specified domain of
28bs_bs_query p-worlds. When these two views are paired, as in the familiar Kratzer 1 29bs_bs_query semantics, they have an unintended consequence: they validate:
30bs_bs_query
31bs_bs_query (1) If p, ought p.
32bs_bs_query 2 33bs_bs_query But obviously not all instances of if p, ought p are trivially true:
34bs_bs_query
35bs_bs_query (2) If you beat up elderly people, you ought to beat up elderly people.
36bs_bs_query
37bs_bs_query This point was first made about deontic conditionals under the restrictor
38bs_bs_query analysis by Frank (1997); Zvolenszky (2002, 2006, 2007) provides detailed
39bs_bs_query investigation. The point generalizes to other analyses of deontic condition-
40bs_bs_query als, and was independently discovered by van Fraassen (1972), Spohn
41bs_bs_query (1975), and Jackson (1985).
Pacific Philosophical Quarterly •• (2014) ••–•• DOI: 10.1111/papq.12048 © 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd.
1 JOBNAME: No Job Name PAGE: 2 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 5335E046 /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
2 PACIFIC PHILOSOPHICAL QUARTERLY
1bs_bs_query If we want to hold onto possible worlds semantics for modals and a
2bs_bs_query restrictor analysis of conditionals, how can we avoid this result? I will
3bs_bs_query argue that doing so is harder than expected. Section 1 introduces the
4bs_bs_query ‘classic’ account of modals and restrictor analysis of conditionals, and
5bs_bs_query explains how they validate if p, ought p. In Section 2, I describe some
6bs_bs_query candidate explanations for how if p, ought p can fail to be true that are
7bs_bs_query consistent with the restrictor analysis combined with possible worlds
8bs_bs_query semantics for modals. According to the most successful of these theories,
9bs_bs_query iffy oughts are systematically ambiguous between a single-modal interpre-
10bs_bs_query tation and a double-modal interpretation. Section 3 discusses a test for
11 bs_bs_query disambiguating the single- and double-modal readings, and shows that
12bs_bs_query this test gives counterexamples to the proposed account. Section 4 surveys
13bs_bs_query strategies for maintaining a conservative semantics while accommodating
14bs_bs_query tough cases. Finally, in Section 5, I provide a positive account. I show that
15bs_bs_query two forms of information-sensitivity affect the interpretation of iffy
16bs_bs_query oughts. Generalizing our account of modals to allow them to vary inde-
17bs_bs_query pendently of each other makes it possible to model and predict problem
18bs_bs_query cases.
19bs_bs_query
20bs_bs_query 1. The problem
21bs_bs_query
22bs_bs_query 1.1. A SIMPLIFIED KRATZER SEMANTICS
23bs_bs_query
24bs_bs_query Why is the schema if p, ought p predicted to be valid? Because the condi-
25bs_bs_query tional is true iff in all the best possible p-worlds, p is true.
26bs_bs_query To show this more carefully, let’s briefly rehearse the Kratzer account of
27bs_bs_query conditionals, which has long been the default theory in linguistic seman-
28bs_bs_query tics. According to Kratzer semantics, conditionals are a kind of quantified
29bs_bs_query sentence; usually involving a modal quantifier. Modals, in this view, are
30bs_bs_query given a possible worlds interpretation: ought p is true iff p is true at all the 3 4 5 31bs_bs_query best worlds that are possible, given the circumstances. , ,
32bs_bs_query Two elements of this analysis are contextually determined: what’s best
33bs_bs_query and what’s possible given the circumstances. There are different ways of
34bs_bs_query modeling these two contextual parameters. Kratzer models them with two
35bs_bs_query sets of propositions (i.e. sets of sets of worlds): a modal base, which is a set
36bs_bs_query of propositions characterizing the circumstances (determining the set of
37bs_bs_query relevant possible worlds), and an ordering source, which determines a 6 38bs_bs_query pre-order over worlds. (The preorder can be used to represent the relation
39bs_bs_query of comparative deontic ideality, teleological ideality, epistemic plausibil-
40bs_bs_query ity, and so on.)
41bs_bs_query For ease of exposition, I will model these with simpler and more ideal-
42bs_bs_query ized tools: a set of worlds and a (total) ordering. (See Figure 1.) The modal
43bs_bs_query background, f, is the set of worlds that are possible given the circum-
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 3 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 54B64968 /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
THE IF P, OUGHT P PROBLEM 3
1bs_bs_query stances (for example, epistemically possible worlds). The ordering, g,
2bs_bs_query ranks worlds in terms of ideality of some sort or other; we’ll focus on
3bs_bs_query deontic ideality. These jointly determine the domain of the modal:
4bs_bs_query
5bs_bs_query DOMAINS: domain(w, f, g) is the set of worlds in the modal back-
6bs_bs_query ground f ranked highest by the ordering g.
7bs_bs_query
8bs_bs_query The official statement of this simplified Kratzer semantics:
9bs_bs_query
10bs_bs_query MODALS: ought p is true at 〈w, f, g〉 iff p is true at all w′∈domain(w,
11 bs_bs_query f, g).
12bs_bs_query
13bs_bs_query Conditionals are, on this view, modals that have a restriction on the
14bs_bs_query modal background. The if-clause restricts that set of worlds: if p, ought q
15bs_bs_query takes the set of worlds in the modal background f and eliminates all the
16bs_bs_query worlds where p is false. ought q is evaluated relative to the remaining set of
17bs_bs_query worlds. In Figure 2, I represent restrictions diagrammatically by graying
18bs_bs_query out a portion of the modal background.
19bs_bs_query Official statement:
20bs_bs_query
21bs_bs_query CONDITIONALS: if p, ought q is true at 〈w, f, g〉 iff q is true at
22bs_bs_query domain(w, f + p, g) where ‘f + p’ is shorthand for the intersection of f and
23bs_bs_query the set of worlds where p is true.
24bs_bs_query
25bs_bs_query 1.2. THE PUZZLING CONSEQUENCE
26bs_bs_query
27bs_bs_query From here, it’s easy to see how CONDITIONALS validates if p, ought p,
28bs_bs_query relative to any world-modal background-ordering triple. if p, ought p is
29bs_bs_query
30bs_bs_query Figure 1 Modals.
31bs_bs_query
32bs_bs_query Figure 2 Conditionals.
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 4 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 5FE62A4E /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
4 PACIFIC PHILOSOPHICAL QUARTERLY
1bs_bs_query true iff p is true in all of the g-ideal p-worlds that are possible according to
2bs_bs_query f. It’s trivial that p is true in all the p-worlds in any set of worlds.
3bs_bs_query When the necessity modal is epistemic, the triviality of if p, ought p is 7 8 4bs_bs_query unproblematic: ,
5bs_bs_query
6bs_bs_query ✓ 3 (3) If it’s raining, it must be raining. bs_bs_query
7bs_bs_query (4) If she’s not home, she must not be home. ✓
8bs_bs_query
9bs_bs_query Similarly, as Zvolenszky (2006) notes, with appropriate context, related
10bs_bs_query teleological examples may be interpreted as trivial. They are uninforma-
11 bs_bs_query tive but not false:
12bs_bs_query
13bs_bs_query (5) a. A: What do I have to do to go to Berlin?
14bs_bs_query b. B: To go to Berlin, you have to go to Berlin. ✓
15bs_bs_query c. B: If you want to go to Berlin, you have to go to Berlin. ✓
16bs_bs_query
17bs_bs_query But when the modal is interpreted as deontic, there are clear
18bs_bs_query counterexamples:
19bs_bs_query
20bs_bs_query (6) If you beat up elderly people, you ought to beat up elderly people.
21bs_bs_query ✗
22bs_bs_query (7) If John spills wine, he should spill wine. ✗
23bs_bs_query 9 24bs_bs_query Similarly for circumstantial modals.
25bs_bs_query
26bs_bs_query (8) a. If the coin lands heads, the coin has to land heads. ✗
27bs_bs_query b. (Equivalently) If the coin lands heads, the coin can’t not land
28bs_bs_query heads. ✗
29bs_bs_query
30bs_bs_query Perhaps the clearest examples involve nomological necessity. Suppose the
31bs_bs_query trajectory of a silver ion after passing through a Stern-Gerlach magnet is
32bs_bs_query presupposed to be indeterministic. Then the following utterance, inter-
33bs_bs_query preted as a circumstantial modal, is false:
34bs_bs_query
35bs_bs_query (9) If the silver ion veers upward, then it must veer upward. ✗
36bs_bs_query
37bs_bs_query The if p, ought p problem is even more general. Sentences of the following
38bs_bs_query forms are also made trivially true:
39bs_bs_query 10 40bs_bs_query (10) If p, may p.
41bs_bs_query (11) It’s not the case that if p, not ought p.
42bs_bs_query (12) It’s not the case that if p, may not p.
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 5 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 5155A271 /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
THE IF P, OUGHT P PROBLEM 5
1bs_bs_query These are equally unattractive results. (The reader may generate her own
2bs_bs_query counterexamples.)
3bs_bs_query I’ll focus on Kratzer’s restrictor analysis because it is widely accepted in
4bs_bs_query linguistic semantics, and because generalizing the discussion to other theo-
5bs_bs_query ries of conditionals would interfere with the exposition. But it’s worth
6bs_bs_query noting that these and related problems afflict many other theories of
7bs_bs_query conditionals, including the material conditional analysis and the Stalnaker
8bs_bs_query semantics. Explaining why will require more setup, so I put it off until
9bs_bs_query Section 2.2. The focus, going forward, will be Kratzer semantics. My
10bs_bs_query central question will be: if we want to hold onto a restrictor analysis of
11 bs_bs_query conditionals and a possible worlds account of modals, how can we avoid
12bs_bs_query these results?
13bs_bs_query
14bs_bs_query 2. Some hypotheses
15bs_bs_query
16bs_bs_query 2.1. HYPOTHESIS #1: THE DIVERSITY CONDITION
17bs_bs_query
18bs_bs_query What’s wrong with sentences like: ‘If you beat up elderly people, you
19bs_bs_query ought to beat up elderly people’? A first suggestion: let’s consider this in
20bs_bs_query conjunction with A. N. Prior’s (1958) Samaritan Paradox:
21bs_bs_query
22bs_bs_query (13) a. John should help the assault victim.
23bs_bs_query b. Doesn’t entail: Therefore, there should be an assault victim.
24bs_bs_query
25bs_bs_query It would, of course, be a bad result if (13a) entailed (13b). But the
26bs_bs_query familiar semantics for modals generates this entailment, as long as (13a)
27bs_bs_query and (13b) are evaluated relative to the same modal background and order-
28bs_bs_query ing. If all the worlds in the domain are worlds where John helps the victim,
29bs_bs_query then trivially all the worlds in the domain include a victim.
30bs_bs_query The Samaritan Paradox suggests that deontic modals have a diversity
31bs_bs_query condition on their modal backgrounds:
32bs_bs_query
33bs_bs_query DIVERSITY: ought p presupposes that the modal background includes
34bs_bs_query both p and ¬p worlds.
35bs_bs_query
36bs_bs_query If there is a diversity condition on modal backgrounds (under some
37bs_bs_query circumstances), then (13b) can’t be evaluated at the kind of modal back-
38bs_bs_query ground where (13a) is most naturally assessed, i.e. a modal background
39bs_bs_query that presupposes the existence of an assault victim. Instead, it must include
40bs_bs_query the possibility of there being no assault victim. But if the modal back-
41bs_bs_query ground allows that there might be no assault victim, then on natural
42bs_bs_query assumptions about what is most ideal, at least some worlds where there is
43bs_bs_query no assault victim are better than worlds where someone is assaulted, but
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 6 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 4F2FA958 /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
6 PACIFIC PHILOSOPHICAL QUARTERLY
1bs_bs_query then John helps them. And so, (13b) will be evaluated relative to a different
2bs_bs_query modal background from (13a), and at one where (13b) is correctly pre-
3bs_bs_query dicted to be false.
4bs_bs_query It is worth mentioning that the diversity condition also has some inde-
5bs_bs_query pendent, intuitive plausibility, at least in the deontic case. It’s plausible
6bs_bs_query that deontic ought implies both can and can not.
7bs_bs_query As Frank (1997) first noted, a diversity condition can helps with if p,
8bs_bs_query ought p: when the if-clause removes from the modal background all the
9bs_bs_query ¬p-worlds, the modal background at which ought p is evaluated can’t
10bs_bs_query respect the diversity condition. So if p, ought p suffers presupposition
11 bs_bs_query failure.
12bs_bs_query Problem solved? Unfortunately, no: there are serious objections to this
13bs_bs_query account. First: consider our example: ‘If you beat up elderly people, you
14bs_bs_query ought to beat up elderly people.’ This sentence doesn’t seem to suffer
15bs_bs_query presupposition failure. It isn’t judged non-truth-evaluable. It is judged 11 16bs_bs_query straightforwardly false.
17bs_bs_query Second, a diversity condition may help with if p, ought p, but it doesn’t
18bs_bs_query help with the corresponding may-conditional. If anything, the problem is
19bs_bs_query worse: a diversity condition would validate all instances of both if p, may
20bs_bs_query p and if p, may ¬p. But both have counterexamples.
21bs_bs_query Finally, we don’t want to predict that if p, ought p is always defective. As
22bs_bs_query Frank (1997) and Zvolenszky (2002, 2007) argue, there are cases where
23bs_bs_query such sentences are judged both true and informative:
24bs_bs_query
25bs_bs_query (14) a. John knows the route well, so if John turns on Exit 49, then
26bs_bs_query he should turn on Exit 49.
27bs_bs_query b. Ryan is a workaholic, so if Ryan is taking a break, he has to
28bs_bs_query take a break.
29bs_bs_query
30bs_bs_query The diversity condition would make it the case that the sentences in (14)
31bs_bs_query cannot be true: they are immediately defective. So we can’t explain away
32bs_bs_query the problem with validating if p, ought p simply by imposing a diversity
33bs_bs_query condition on the modal background. At the very least, it can’t be the whole
34bs_bs_query story; we need to accommodate the truth of some instances of if p,
35bs_bs_query ought p.
36bs_bs_query
37bs_bs_query 2.2. HYPOTHESIS #2: DOUBLE MODALIZATION
38bs_bs_query
39bs_bs_query Let’s consider an alternative proposal. The restrictor analysis is committed
40bs_bs_query to conditionals being a form of restricted modal. The analysis assumes that
41bs_bs_query when an overt modal appears in the consequent of a conditional, its modal
42bs_bs_query background is the one that’s restricted by the if-clause. For bare condi- 12 43bs_bs_query tionals, there’s a covert epistemic must:
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 7 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 5BA53E5F /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
THE IF P, OUGHT P PROBLEM 7
1bs_bs_query (15) a. If John spilled his wine, he’s drunk.
2bs_bs_query b. If John spilled his wine, he must be drunk.
3bs_bs_query
4bs_bs_query In other words: in some cases, the modals that if-clauses restrict are
5bs_bs_query pronounced; in other cases, unpronounced.
6bs_bs_query Suppose instead that the covert modal is there whether or not there is an
7bs_bs_query overt modal in the consequent. When an overt deontic modal appears, it is
8bs_bs_query embedded under the covert epistemic modal. So a sentence like ‘If it’s
9bs_bs_query raining, you should take an umbrella’ actually has the form: if p, ✓e✓dq
10bs_bs_query (where ✓ is a necessity modal like ought or must, and subscripted e and d
11 bs_bs_query designate epistemic and deontic modality, respectively). In order to evalu-
12bs_bs_query ate the conditional, we look at p-worlds in the epistemic modal back-
13bs_bs_query ground and evaluate each pointwise for the truth of oughtd q. (See Figure 3
14bs_bs_query for a diagrammatic representation.)
15bs_bs_query How this helps with our if p, ought p problem: the restriction imposed by
16bs_bs_query the if-clause restricts the epistemic modal, but not the deontic modal
17bs_bs_query embedded under it. The deontic modal’s modal background is not
18bs_bs_query restricted. And so the antecedent p isn’t automatically true at all of the
19bs_bs_query worlds in the deontic modal’s modal background.
20bs_bs_query We look at all points in the epistemic modal background where you beat
21bs_bs_query elderly people, and evaluate each pointwise for the truth of You ought to
22bs_bs_query beat up elderly people. You ought to beat up elderly people is true at an
23bs_bs_query epistemically possible point iff You beat up elderly people is true in the best
24bs_bs_query worlds that are possible, given the circumstances (i.e. in the deontic
25bs_bs_query modal’s unrestricted modal background). Let’s see how this result is
26bs_bs_query achieved in the case of (6).
27bs_bs_query
28bs_bs_query (6) a. If you beat up elderly people, you ought to beat up elderly
29bs_bs_query people.
30bs_bs_query b. If you beat up elderly people, it must be that you ought to beat
31bs_bs_query up elderly people.
32bs_bs_query
33bs_bs_query Figure 3 Double-modal conditionals.
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 8 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 4926C3B6 /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
8 PACIFIC PHILOSOPHICAL QUARTERLY
1bs_bs_query But given the circumstances, it’s possible for you not to beat up elderly
2bs_bs_query people: even if you will in fact beat them up, you have the ability not to. So
3bs_bs_query in the best worlds in the deontic modal background, you don’t beat up
4bs_bs_query elderly people. Therefore, it’s not automatically the case that at each
5bs_bs_query epistemically possible world where you beat up elderly people, you ought
6bs_bs_query to beat up elderly people. So (2) is false.
7bs_bs_query It’s easy to see how this also delivers the correct results for if p, ought p
8bs_bs_query sentences that have true readings, by the very same reasoning. In these
9bs_bs_query cases, the if-clause restricts the epistemic modal but not the deontic modal.
10bs_bs_query So the deontic modal’s modal background can still satisfy the diversity
11 bs_bs_query condition (if such a condition exists). And so this view can handle the
12bs_bs_query objections to hypothesis #1.
13bs_bs_query There’s a problem, though. If we model iffy oughts as including two
14bs_bs_query modals, only one of which is restricted by the if-clause, we generate the
15bs_bs_query wrong predictions for most ordinary instances of iffy oughts. A perfectly
16bs_bs_query standard iffy ought:
17bs_bs_query
18bs_bs_query (16) If you turn in your library books late, you have to pay a fine.
19bs_bs_query
20bs_bs_query If we evaluate (16) as doubly modalized in the same way as (2), with
21bs_bs_query plausible assumptions about the conversational background, it comes out
22bs_bs_query false.
23bs_bs_query Take each epistemically possible world where you turn in your library
24bs_bs_query books late, and evaluate whether ‘you have to pay a fine’ is true. The
25bs_bs_query if-clause restricts only the epistemic modal and not the deontic modal.
26bs_bs_query (This assumption is crucial for using the double-modal account to predict
27bs_bs_query contingent instances of if p, ought p.) But because the deontic modal
28bs_bs_query background can include you-don’t-turn-in-books-late-worlds, it’s not the
29bs_bs_query case that you have to pay a library fine: in some worlds (indeed, the best
30bs_bs_query worlds), you don’t even have library fines. And so you don’t have to pay
31bs_bs_query library fines. The (16) is incorrectly predicted to be false. So the double-
32bs_bs_query modal, single-restriction hypothesis isn’t true, or at least isn’t fully general.
33bs_bs_query The general question: how do we provide a unified account of condi-
34bs_bs_query tionals like (16), where the antecedent acts as a restrictor on the deontic
35bs_bs_query modal, and conditionals like (2), where the antecedent does not? This
36bs_bs_query puzzle equally afflicts other analyses of conditionals, e.g. the material
37bs_bs_query conditional account and the Stalnaker account. I will offer a very quick
38bs_bs_query argument, for those familiar with the two views. (Other readers may prefer
39bs_bs_query to skip ahead to the next subsection.)
40bs_bs_query First, the material conditional analysis doesn’t predict any semantic
41bs_bs_query interaction between if-clauses and deontic modals. So that view is ill-
42bs_bs_query equipped to give an adequate semantics for run-of-the-mill iffy oughts like
43bs_bs_query If you’re going to murder, you should murder gently. The truth of that
44bs_bs_query conditional is compatible with the truth of the negation of the consequent,
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 9 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 534A265B /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
THE IF P, OUGHT P PROBLEM 9
1bs_bs_query You ought not murder gently, even at worlds where in fact the addressee is
2bs_bs_query going to murder. The material conditional analysis can’t be updated to
3bs_bs_query incorporate the systematic restriction of embedded modals by the ante-
4bs_bs_query cedent without thereby losing the analyses defining features, e.g. the valid-
5bs_bs_query ity of classical inference rules.
6bs_bs_query Second: Stalnaker semantics for conditionals is silent on the relation
7bs_bs_query between modals and conditionals. But there are two basic strategies avail-
8bs_bs_query able to Stalnaker semantics: first, it could vary the selection function to a
9bs_bs_query deontic selection function when there’s a deontic modal in the consequent
10bs_bs_query of the conditional. In that case, if p, ought p will be valid. So this is no
11 bs_bs_query progress. Second, it could retain a non-deontic selection function and
12bs_bs_query simply evaluate deontic modal at the selected antecedent-world. In that
13bs_bs_query case, Stalnaker semantics will make the wrong predictions for ordinary iffy
14bs_bs_query oughts like (16). And so the Stalnaker account is in the same position as the
15bs_bs_query Kratzer account.
16bs_bs_query
17bs_bs_query 2.3. HYPOTHESIS #3: HYBRID PROPOSAL
18bs_bs_query
19bs_bs_query Hypothesis #2 suggested that iffy oughts have a covert epistemic modal with
20bs_bs_query a deontic modal embedded under it. The if-clause restricts the epistemic
21bs_bs_query modal rather than the deontic modal. But at least some iffy oughts require
22bs_bs_query a single-modal reading, where the antecedent restricts the deontic modal. A
23bs_bs_query natural hypothesis, then, is that both readings of iffy oughts are available.
24bs_bs_query Conditionals of this kind are systematically structurally ambiguous, with 13 25bs_bs_query both single-modal and double-modal readings. As Geurts (2004) shows,
26bs_bs_query an ambiguity of this sort is widespread in natural language.
27bs_bs_query While this looks to be promising, there’s an immediate concern: on this
28bs_bs_query view, ‘If you smoke, you ought to smoke’ would have to have a reading
29bs_bs_query where it is trivially true. And it doesn’t seem to. Similarly, ‘If you turn in
30bs_bs_query your library books late, you have to pay a fine’ should have a false reading
31bs_bs_query in the very same (natural) context where it has a true reading. If these
32bs_bs_query secondary readings are available at all, they are certainly harder to access.
33bs_bs_query It’s worth asking whether there’s a general explanatory model that would
34bs_bs_query allow us to predict whether the single- or double-modal reading will be
35bs_bs_query dominant for a given conditional.
36bs_bs_query Maybe this worry can be addressed. A naive hypothesis: double
37bs_bs_query modalization is dispreferred and is typically accessible only when the 14 15 38bs_bs_query singly modalized reading is defective. , According to this hypothesis, one
39bs_bs_query circumstance in which the single-modal reading is defective is when it
40bs_bs_query violates the diversity condition. And so sentences like ‘If you smoke, you
41bs_bs_query ought to smoke’ are defective on the single-modal reading, but false on the
42bs_bs_query double-modal reading. On the other hand, ‘If Ryan is taking a break, he
43bs_bs_query has to take a break’ is defective on the single-modal reading, but true on
44bs_bs_query the double-modal reading.
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 10 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 53D30432 /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
10 PACIFIC PHILOSOPHICAL QUARTERLY
1bs_bs_query And so we’re able to predict that if p, ought p is neither trivially true nor
2bs_bs_query trivially not true: some instances are true and some are false. So sentences
3bs_bs_query of this form make substantial claims. (Meanwhile, more commonplace iffy
4bs_bs_query oughts like (16) are not defective, and so are by default interpreted as only
5bs_bs_query involving one modal.) In effect, we have taken the better of the previous
6bs_bs_query two proposals. Each is individually inadequate, but together they make
7bs_bs_query good predictions.
8bs_bs_query
9bs_bs_query 2.4. SINGLE-/DOUBLE-MODAL AMBIGUITY
10bs_bs_query
11 bs_bs_query Geurts (2004) shows that a similar ambiguity appears with other kinds of
12bs_bs_query quantifiers. Conditionals are essential restricted quantifiers over possibil-
13bs_bs_query ities (restricted modals). An example from Geurts’ examples:
14bs_bs_query
15bs_bs_query (17) If Beryl is in Paris, she often visits the Louvre.
16bs_bs_query
17bs_bs_query Here the if-clause can restrict either the overt adverbial quantifier often or
18bs_bs_query it can restrict a covert quantifier. Using the notation Quantifier [restrictor]
19bs_bs_query [nuclear scope], we can spell out the two readings:
20bs_bs_query
21bs_bs_query (18) a. Often [Beryl is in Paris] [Beryl visits the Louvre].
22bs_bs_query b. Must [Beryl is in Paris] [Often [] [Beryl visits the Louvre]]
23bs_bs_query
24bs_bs_query On the single-quantifier reading, (18a), the if-clause restricts the overt
25bs_bs_query quantifier often. (18a) says that among those occasions where Beryl is in
26bs_bs_query Paris, many are such that she visits the Louvre. On the double-quantifier
27bs_bs_query reading, (18b), the if-clause restricts a covert quantifier (plausibly
28bs_bs_query epistemic must). (18b) says that among the epistemic possibilities where
29bs_bs_query Beryl is in Paris, all are such that on many occasions she visits the Louvre.
30bs_bs_query If Geurts is right that this ambiguity is widespread among quantifiers,
31bs_bs_query it’s predictable that the single-/double-modal ambiguity would appear
32bs_bs_query conditionals. The contrast between single-modal iffy deontic oughts and
33bs_bs_query double-modal deontic iffy oughts seems to be a contrast between condi-
34bs_bs_query tionals that express conditional obligations and conditionals that don’t. In
35bs_bs_query the latter cases, the antecedent merely provides evidence that supports the
36bs_bs_query independent truth of the ought claim. Rough (!) glosses to exhibit the
37bs_bs_query difference:
38bs_bs_query
39bs_bs_query (19) If you spill wine, you have to mop.
40bs_bs_query a. Conditional obligation gloss: On the condition that you spill
41bs_bs_query wine, you have to mop.
42bs_bs_query b. ≠Epistemic conditional gloss: If you spill wine, then you must
43bs_bs_query have to mop (already).
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 11 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 615826B7 /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
THE IF P, OUGHT P PROBLEM 11
1bs_bs_query (20) If Ryan is taking a break, he has to take a break.
2bs_bs_query a. Epistemic conditional gloss: If Ryan is taking a break, then
3bs_bs_query Ryan must have to take a break.
4bs_bs_query b. ≠ Conditional obligation gloss: Ryan has to take a break on
5bs_bs_query the condition that he is taking a break.
6bs_bs_query
7bs_bs_query A first-pass explanation of the distinction: in double-modal conditionals,
8bs_bs_query the if-clause provides evidence for the obligation in the consequent. In
9bs_bs_query single-modal conditionals, by contrast, the if-clause notes the circum-
10bs_bs_query stances where the obligation obtains. Single-modal deontic conditionals
11 bs_bs_query are typically used to express hypothetical imperatives or conditional obli-
12bs_bs_query gations. Double-modal conditionals, by contrast, express something like
13bs_bs_query speculation about possible obligations. For the moment, hopefully this
14bs_bs_query rough characterization will suffice to distinguish the two types of iffy
15bs_bs_query ought.
16bs_bs_query
17bs_bs_query 3. Puzzle cases
18bs_bs_query
19bs_bs_query 3.1. BACKGROUND ON INFORMATION-SENSITIVE DEONTIC MODALS
20bs_bs_query
21bs_bs_query The problem that I will generate from the ambiguity account, and the
22bs_bs_query solution that I propose, are tightly related to phenomena that central to 16 23bs_bs_query the recent literature on the Miners Puzzle. The kinds of information-
24bs_bs_query sensitivity I will discuss share many of the features of the Miners Puzzle
25bs_bs_query (though not those that have been the core of the recent debate on so-called
26bs_bs_query ‘serious information-sensitivity’). So it will be helpful to provide some
27bs_bs_query background on the Miners’ Puzzle phenomena.
28bs_bs_query The original Miners Puzzle, introduced to the philosophy of language 17 29bs_bs_query literature in Kolodny and MacFarlane, 2010, runs as follows:
30bs_bs_query
31bs_bs_query The Miners Puzzle.
32bs_bs_query Ten miners are trapped either in shaft A or in shaft B, but we do not know which. [They are
33bs_bs_query equally likely to be in either.] Flood waters threaten to flood the shafts. We have enough
34bs_bs_query sandbags to block one shaft, but not both. If we block one shaft, all the water will go into the
35bs_bs_query other shaft, killing any miners inside it. If we block neither shaft, both shafts will fill halfway
36bs_bs_query with water, and just one miner, the lowest in the shaft, will be killed (Kolodny and
37bs_bs_query MacFarlane, 2010, p. 115).
38bs_bs_query
39bs_bs_query In this context, the sentences in (21) are all true:
40bs_bs_query
41bs_bs_query (21) a. We ought to block neither shaft.
42bs_bs_query b. If the miners are in shaft A, we ought to block shaft A.
43bs_bs_query c. If the miners are in shaft B, we ought to block shaft B.
44bs_bs_query d. The miners are either in shaft A or in shaft B.
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 12 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 4CDADAA4 /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
12 PACIFIC PHILOSOPHICAL QUARTERLY
1bs_bs_query Kolodny and MacFarlane argue that this case reveals two features of
2bs_bs_query information-sensitive deontic modals, e.g. the so-called subjective ought.
3bs_bs_query First, conditionals involving these modals can generate counterexamples
4bs_bs_query to classical inference rules, e.g. (at least) proof by cases and modus tollens.
5bs_bs_query (For arguments against alternative explanations for the apparent consist-
6bs_bs_query ency of the sentences in (21), e.g. context-sensitivity or wide-scoping, see
7bs_bs_query 4 Kolodny and MacFarlane, 2010; Cariani, Kaufmann and Kaufmann, bs_bs_query
8bs_bs_query 2012; Carr, 2012; and Silk, 2014.) This fact about iffy oughts is consistent
9bs_bs_query with Kratzer semantics.
10bs_bs_query Second, Kolodny and MacFarlane argue that this case reveals that
11 bs_bs_query ought is ‘seriously information-sensitive’: roughly, that the ordering of
12bs_bs_query worlds at a context is a function of the modal background, rather than an
13bs_bs_query independent parameter. In other words, changes in contextually salient
14bs_bs_query information can alter not just which worlds are circumstantially possible,
15bs_bs_query but which words are better than which. This fact about iffy oughts is not
16bs_bs_query consistent with Kratzer semantics.
17bs_bs_query Why does the deontic ordering change with changes in the modal back-
18bs_bs_query ground? In (21a), block-neither-worlds are better than both block-A-
19bs_bs_query worlds and block-B-worlds. When the modal background is restricted by
20bs_bs_query an if-clause, as in (21b) and (21c), block-neither-worlds are worse than
21bs_bs_query either block-A-worlds or block-B-worlds, even though all three types of
22bs_bs_query world are still present in the restricted modal background. So the ordering
23bs_bs_query must change.
24bs_bs_query An intuitive explanation for why iffy oughts generate both coun-
25bs_bs_query terexamples to classical inference rules and serious information
26bs_bs_query sensitivity:
27bs_bs_query The body of information that is relevant for information-sensitive
28bs_bs_query modals is not always the speaker’s, evaluator’s, or conversational partici-
29bs_bs_query pants’. Under embeddings, the relevant body of information may often be
30bs_bs_query a modified variant of the contextually salient information. In particular,
31bs_bs_query in the consequent of a conditional, the salient information for an
32bs_bs_query information-sensitive modal will be the speakers’ information augmented
33bs_bs_query with the information in the antecedent. For example, consider the follow-
34bs_bs_query ing epistemically modalized conditional:
35bs_bs_query
36bs_bs_query 5 (22) If his lights are off, he must not be in his office. bs_bs_query
37bs_bs_query
38bs_bs_query This can be uttered in a context where no one has any idea whether
39bs_bs_query he’s in his office – i.e. where no one’s body of information can be
40bs_bs_query expressed by the consequent: he must be in his office. The modal instead
41bs_bs_query quantifies over possibilities in the information state consisting of,
42bs_bs_query say, the speaker’s information augmented by the information in the
43bs_bs_query antecedent.
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 13 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 53703C9F /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
THE IF P, OUGHT P PROBLEM 13
1bs_bs_query The same phenomena affect other information-sensitive operators, e.g.
2bs_bs_query probably:
3bs_bs_query
4bs_bs_query (23) If his lights are off, he’s probably not in his office.
5bs_bs_query
6bs_bs_query And the same phenomena affect information-sensitive deontic modals.
7bs_bs_query Again, in intuitive terms: in the Miners Puzzle (21a), there’s a salient
8bs_bs_query subjective reading of the ought. The salient priority determining the order-
9bs_bs_query ing is to aim to save as many miners’ lives as possible, in light of the
10bs_bs_query speaker’s limited information. We might think of the salient priority as
11 bs_bs_query maximizing the expected number of miner’s lives saved. (There are, of
12bs_bs_query course, plenty of other norms that equally recommend hedging one’s bets
13bs_bs_query in cases where information is limited.) Suppose this is the very same
14bs_bs_query priority in the Miners Puzzle conditional (21b). Suppose further that, as
15bs_bs_query with (21), the salient body of information for the embedded modal is not
16bs_bs_query the speaker’s, but rather the speaker’s information augmented with the
17bs_bs_query information in the antecedent (that the miners are in shaft A). Relative to
18bs_bs_query the augmented body of information, the subjectively best thing to do is to
19bs_bs_query block shaft A. If the priority is to maximize expected miners’ lives, then for
20bs_bs_query the conditional, that expectation is relativized not to the speaker’s actual
21bs_bs_query credence function, but rather to their credence function augmented by
22bs_bs_query (conditionalized on) the information in the antecedent. And so this is the
23bs_bs_query option that maximizes the expected number of miners’ lives. This is why
24bs_bs_query the conditionals can be true relative to the same contextual parameters as
25bs_bs_query the unconditional claim (21a).
26bs_bs_query Notice that this goes beyond the information-sensitivity suggested by
27bs_bs_query Kratzer semantics. There, the antecedent affects the contextually salient
28bs_bs_query information only by generating changes in the modal background. The
29bs_bs_query Miners Puzzle shows that information from the antecedent can also affect
30bs_bs_query the ordering of options, without any change in the contextual parameters.
31bs_bs_query For example, if the prioritizing parameter is fixed by a contextually salient
32bs_bs_query priority to maximize expected miners’ lives, then the probability function
33bs_bs_query used for the expectation is not the speaker’s probability function, but
34bs_bs_query rather the antecedent-augmented probability function. So the ordering
35bs_bs_query generated by this priority shifts with linguistically generated information,
36bs_bs_query not speakers’ actual information.
37bs_bs_query So: the body of information relevant for information-sensitive opera-
38bs_bs_query tors embedded in the consequents of conditionals is not the contextually
39bs_bs_query salient body of knowledge, but rather that information augmented by
40bs_bs_query the information in the antecedent. This is true not just for modal back-
41bs_bs_query grounds, but also for the deontic priorities that generate orderings for
42bs_bs_query the modal. This conclusion is not entirely uncontroversial, but I won’t 18 43bs_bs_query defend it further. I will assume its correctness for the puzzle cases I
44bs_bs_query discuss below.
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 14 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 4A29A89F /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
14 PACIFIC PHILOSOPHICAL QUARTERLY
1bs_bs_query 3.2. A NEGATIVE TEST FOR EPISTEMIC CONDITIONALS
2bs_bs_query
3bs_bs_query In many circumstances it will not be clear whether the salient reading of an
4bs_bs_query iffy ought is single- or double-modal. So it would be useful to have a test
5bs_bs_query for single- and double-modal iffy oughts. Here is a (partial) candidate:
6bs_bs_query If iffy oughts are ambiguous, they generate ambiguity in argument
7bs_bs_query forms. If you give a modus tollens-style argument with an iffy ought, your
8bs_bs_query argument will be ambiguous between the following two forms.
9bs_bs_query Modus tollens
10bs_bs_query if p, □dq¬
11 bs_bs_query □dq
12bs_bs_query Doesn’t entail: ¬ p
13bs_bs_query Quasi-modus tollens
14bs_bs_query if p, □e□dq
15bs_bs_query ¬ □dq
16bs_bs_query Does entail: ¬ p
17bs_bs_query On the standard semantics, epistemic conditionals, including double-
18bs_bs_query modal iffy oughts, respect quasi-modus tollens (though not modus 19 19bs_bs_query tollens). As the literature on the Miners Puzzle has emphasized (espe-
20bs_bs_query cially Kolodny and MacFarlane, 2010), single-modal iffy oughts need not 20,21 21bs_bs_query respect modus tollens.
22bs_bs_query Assuming that iffy oughts can have a covert epistemic modal, the two
23bs_bs_query arguments might be expressed in English in exactly the same way. So, a
24bs_bs_query prima facie plausible hypothesis: we can learn that an iffy ought is not an
25bs_bs_query epistemic conditional if it appears to violate modus tollens-style reasoning.
26bs_bs_query As the name suggests, quasi-modus tollens is not actually modus tollens.
27bs_bs_query For this sort of conditional, the second premise would be the weaker
28bs_bs_query claim: ¬ □e□dq. Epistemic conditionals need not respect modus tollens,
29bs_bs_query but prima facie, they do seem to respect quasi-modus tollens.
30bs_bs_query Modus tollens
31bs_bs_query If it’s raining, the streets must be wet.
32bs_bs_query The streets might not be wet.
33bs_bs_query Doesn’t entail: Then it’s not raining.
34bs_bs_query Quasi-modus tollens
35bs_bs_query If it’s raining, the streets must be wet.
36bs_bs_query The streets are not wet.
37bs_bs_query Does entail: Then it’s not raining.
38bs_bs_query Now, the most predictive account we have so far combines the single-/
39bs_bs_query double-modal ambiguity with a diversity condition on deontic modal
40bs_bs_query backgrounds. That account predicts that there are no true, single-modal
41bs_bs_query instances of if p, ought p.
42bs_bs_query Can we find true instances of if p, ought p that generate violations of
43bs_bs_query MT-style reasoning? If so, then according to our test, that account won’t
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 15 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 5179B0E2 /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
THE IF P, OUGHT P PROBLEM 15
1bs_bs_query work. Such cases can’t be double-modal because quasi-MT is (we hypoth-
2bs_bs_query esize) valid. And they also can’t be single-modal because they would
3bs_bs_query violate the diversity condition.
4bs_bs_query
5bs_bs_query 3.3. STRUCTURAL AMBIGUITY + DIVERSITY + QUASI-MT:
6bs_bs_query COUNTEREXAMPLE
7bs_bs_query
8bs_bs_query We can find such cases in decision theory. I will focus on cases that have
9bs_bs_query the same format as the Miners Puzzle, that is, on cases that generate
10bs_bs_query violations of proof by cases. The information-sensitive modal behaves in
11 bs_bs_query the way that, I argued in Section 3.1, is standard for information-sensitive
12bs_bs_query modals: in the consequent of the conditional, the modal is evaluated
13bs_bs_query relative to the information of the consequent augmented by the informa-
14bs_bs_query tion from the antecedent.
15bs_bs_query
16bs_bs_query Self-reinforcing ought
17bs_bs_query Suppose your norm for behavior is to satisfy the desires you anticipate
18bs_bs_query having in the future: roughly, to act in such a way that you think you’ll
19bs_bs_query be glad you did. You are in some decision situation with more than one
20bs_bs_query option such that, predictably, if you choose that option, some ration-
21bs_bs_query alization process will kick in such that you’ll retroactively desire that 22 22bs_bs_query you chose that option.
23bs_bs_query
24bs_bs_query (24) a. If you choose the tapas restaurant, you ought to choose the
25bs_bs_query tapas restaurant.
26bs_bs_query b. If you choose the Indian restaurant, you ought to choose the
27bs_bs_query Indian restaurant.
28bs_bs_query c. You may choose the tapas restaurant and you may choose
29bs_bs_query the Indian restaurant. (It’s not the case that you ought to
30bs_bs_query choose the tapas restaurant and it’s not the case that you
31bs_bs_query ought to choose the Indian restaurant.)
32bs_bs_query d. You will choose the tapas restaurant or the Indian
33bs_bs_query restaurant.
34bs_bs_query
35bs_bs_query Our test for epistemic conditionals suggests that (24a) and (24b) should be
36bs_bs_query interpreted as conditional obligations and so it must be given a single-
37bs_bs_query modal reading. After all, quasi-modus tollens fails. But the diversity con-
38bs_bs_query dition predicts that on the single-modal reading, (24a) and (24b) suffers
39bs_bs_query presupposition failure.
40bs_bs_query So, given that the sentences in (24) are true, they can’t be interpreted as
41bs_bs_query a single-modal iffy ought: this violates the diversity condition. But they
42bs_bs_query also can’t be interpreted as a double-modal iffy ought: this violates quasi-
43bs_bs_query modus tollens.
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 16 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 53FE0DA5 /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
16 PACIFIC PHILOSOPHICAL QUARTERLY
1bs_bs_query 3.4. STRUCTURAL AMBIGUITY + QUASI-MT −
2bs_bs_query DIVERSITY: COUNTEREXAMPLE
3bs_bs_query
4bs_bs_query One might say: perhaps we can get rid of the diversity constraint. After all,
5bs_bs_query it’s not so bad to allow that there might be recessive trivially true readings
6bs_bs_query of sentences like if you smoke, you should smoke. Ordinary language users
7bs_bs_query will tend to interpret contributions to the conversation as being informa-
8bs_bs_query tive (not trivially true), and so the contingent, double-modal reading will
9bs_bs_query be salient.
10bs_bs_query But biting the bullet on this matter won’t help: it can only explain
11 bs_bs_query self-reinforcing cases like (24), but not self-frustrating cases. We can gen-
12bs_bs_query erate other sorts of counterexamples to other schemas that the restrictor
13bs_bs_query account, combined with possible worlds semantics for modals, makes false
14bs_bs_query predictions about. For example, all instances of if p, ought not p are
15bs_bs_query predicted to be trivially false.
16bs_bs_query A counterexample, again with a structure similar to the Miners Puzzle
17bs_bs_query examples, and again taken from decision theory (via Gibbard and Harper,
18bs_bs_query 6 1978): bs_bs_query
19bs_bs_query
20bs_bs_query Self-frustrating ought
21bs_bs_query If you are in the same city as Death tomorrow, then you’ll die. Death has
22bs_bs_query planned to be wherever he predicts you’ll be, and he’s very reliable in such
23bs_bs_query predictions. Your options are to stay in Damascus or to go to Aleppo.
24bs_bs_query But, as you know, if you stay in Damascus, then that’s excellent evidence 23 25bs_bs_query that Death will already be there. Similarly for going to Aleppo.
26bs_bs_query
27bs_bs_query Once again, we can generate a violation of modus-tollens-like reasoning:
28bs_bs_query
29bs_bs_query (25) a. If you go to Aleppo, you ought not go to Aleppo (because
30bs_bs_query Death will be there).
31bs_bs_query b. If you stay in Damascus, you ought not stay in Damascus
32bs_bs_query (because Death will be there).
33bs_bs_query c. You may go to Aleppo and you may stay in Damascus. (It’s
34bs_bs_query not the case that you ought not go to Aleppo and it’s not the
35bs_bs_query case that you ought not stay in Damascus.)
36bs_bs_query
37bs_bs_query Gibbard and Harper’s discussion of this example in the decision-theoretic
38bs_bs_query context provides a justification for accepting the conditional (25a): ‘Any
39bs_bs_query reason the doomed man has for thinking he will go to Aleppo is a reason
40bs_bs_query for thinking he would live longer if he stayed in Damascus, and any reason
41bs_bs_query he has for thinking he will stay in Damascus is a reason for thinking he
42bs_bs_query would live longer if he stayed in Aleppo. Thinking he will do one is a
43bs_bs_query 7 reason for doing the other’ (Gibbard and Harper, 1978, p. 156). bs_bs_query
44bs_bs_query The conditional (25a) can’t be a double-modal iffy ought: it would
45bs_bs_query violate quasi-MT. And it can’t be a single-modal iffy ought, for then the
46bs_bs_query restrictor analysis predicts it to be trivially false.
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 17 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 52A7A42E /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
THE IF P, OUGHT P PROBLEM 17
1bs_bs_query The Death in Damascus example will be central for the remaining
2bs_bs_query discussion, so it’s helpful to understand its dialectical role. Some philoso-
3bs_bs_query phers may want to challenge the data, typically by arguing that the con-
4bs_bs_query ditionals (25a) and (25b) are false. I think these arguments often depend on
5bs_bs_query false theoretic presuppositions rather than naked intuition. In particular,
6bs_bs_query there is an entrenched but false theoretical presupposition that proof by
7bs_bs_query cases is valid. But the Miners Puzzle shows that this is false; and indepen-
8bs_bs_query dently, the standard semantics for conditionals never validated proof by
9bs_bs_query cases.
10bs_bs_query The sentences in the Death in Damascus case are judged acceptable by
11 bs_bs_query many ordinary language speakers. But it’s reasonable to question whether
12bs_bs_query the data are the product of some kind of noise (for example, equivocation),
13bs_bs_query or whether we should take them at face value. Instead of debating the data,
14bs_bs_query let me offer what I take to be strong theoretical considerations in favor of
15bs_bs_query the truth of the Death in Damascus sentences.
16bs_bs_query As I argued in Section 3.1, information-sensitive deontic modals pattern
17bs_bs_query with other information-sensitive modals: the information relevant for the
18bs_bs_query assessment of iffy oughts includes the information in the antecedent. The
19bs_bs_query antecedent’s information can have two effects: it can restrict a modal
20bs_bs_query background, but it can also affect the deontic ordering. So, when the
21bs_bs_query contextually salient priorities or norms are a function of information – for
22bs_bs_query example, when they are expected utility theoretic – then embedded under
23bs_bs_query conditionals, the relevant information for generating the ordering includes
24bs_bs_query the information in the antecedent. Probability functions relevant for max-
25bs_bs_query imizing expectations are updated on the antecedent’s information. This is
26bs_bs_query the lesson of the Miners Puzzle.
27bs_bs_query When we apply this lesson in the Death in Damascus case, the sentences
28bs_bs_query in (25) are exactly as expected. Suppose the contextually salient norm is a
29bs_bs_query form of causal decision theory, where the Death in Damascus case was 24 30bs_bs_query first introduced. Then (25c) will be true iff going to Aleppo and staying
31bs_bs_query in Damascus have equal causal expected utility. Suppose the shoulds in
32bs_bs_query (25a) and (25b) behave in the same way as the Miners Puzzle conditionals
33bs_bs_query do: the information from the antecedent is able to affect the ordering over
34bs_bs_query worlds in the way that conditionalized probabilities affect the ordering of
35bs_bs_query options in decision theory. That assumption, combined with the assump-
36bs_bs_query tion that the relevant priority is to maximize causal expected utility, gen-
37bs_bs_query erates the prediction that if p, ought q will be true iff q uniquely maximizes
38bs_bs_query causal expected utility relative to the relevant probability function
39bs_bs_query conditionalized on p. So we expect (25a) and (25b) to be judged true at
40bs_bs_query such a context, for the same reason that we should be able to predict the
41bs_bs_query truth of (26):
42bs_bs_query
43bs_bs_query (26) If you go to Aleppo, going to Aleppo does not maximize causal
44bs_bs_query expected utility.
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 18 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 49551FFD /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
18 PACIFIC PHILOSOPHICAL QUARTERLY
1bs_bs_query Now we just need a semantic framework that can accommodate this.
2bs_bs_query Finally, note that the aim here is not to give a decision theoretic seman-
3bs_bs_query tics. I do not assume the truth of (any form of) causal decision theory, and
4bs_bs_query I certainly don’t assume that deontically modalized sentences express
5bs_bs_query claims about causal decision theory. What I do assume is that natural
6bs_bs_query language semantics for modals and conditionals is flexible enough to
7bs_bs_query accommodate the various forms of causal decision theory and other nor-
8bs_bs_query mative systems that entail the truth of the Death in Damascus sentences
9bs_bs_query without equivocation. If you don’t accept the sentences, it should be for
10bs_bs_query normative reasons. Their conjunction should not be ruled out as a matter
11 bs_bs_query of linguistic competence.
12bs_bs_query
13bs_bs_query 4. Predicting self-frustrating oughts
14bs_bs_query
15bs_bs_query 4.1. STRUCTURAL AMBIGUITY + DIVERSITY − QUASI-MT
16bs_bs_query
17bs_bs_query Can we avoid the problem by giving up the validity of quasi-MT? We
18bs_bs_query might do so by allowing the ordering for epistemic must to be nontrivial.
19bs_bs_query Doing so gives the epistemic modal the same logic as the deontic modal.
20bs_bs_query must p will be compatible with not p, and so quasi-MT will be no longer
21bs_bs_query valid.
22bs_bs_query But for the purposes of the Death in Damascus example, this strategy
23bs_bs_query doesn’t help: we can simply stipulate that the relevant agent is absolutely
24bs_bs_query certain that Death is a perfect predictor of his whereabouts. And so we can
25bs_bs_query stipulate that it’s a feature of the case that in every epistemically possible
26bs_bs_query world where the agent goes to Aleppo, Death goes too – and so if he goes
27bs_bs_query to Aleppo, it would be better for him to stay in Damascus.
28bs_bs_query Alternatively, it might be thought that we can reject the claim that in this
29bs_bs_query circumstance, there is a quasi-MT violation. It is sometimes thought that
30bs_bs_query the Death in Damascus case generates a rational dilemma, and so (25c) is
31bs_bs_query false.
32bs_bs_query For every location you could go to, Death will have predicted that you’d
33bs_bs_query go there. So we can construct similar conditionals for all such locations: if
34bs_bs_query you go to x, you should not go to x.
35bs_bs_query There are two problems. First, even if this assessment of the rational
36bs_bs_query norms is correct, it doesn’t help us preserve the standard Kratzer seman-
37bs_bs_query tics. That account rules out dilemmas: the modal background must be
38bs_bs_query nonempty, and therefore the domain must be nonempty.
39bs_bs_query Second, if we generalize Kratzer semantics to allow for dilemmas, it’s
40bs_bs_query still a cost to a theory to predict that there must be a dilemma here. Causal
41bs_bs_query decision theory doesn’t treat this as a dilemma. In Section 3.4 I argued that
42bs_bs_query the conditionals should be able to express verdicts of causal decision
43bs_bs_query theory. So even if we wanted to accommodate dilemmas, there’s reason to
44bs_bs_query allow that the Death in Damascus case needn’t generate a dilemma.
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 19 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 46D7226A /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
THE IF P, OUGHT P PROBLEM 19
1bs_bs_query Finally, even if we embrace a theory of modals that allows for deontic
2bs_bs_query dilemmas, we still need an explanation of the truth of the conditional.
3bs_bs_query So far we have none. As I’ll show in Section 4.2, the classical account
4bs_bs_query faces challenges with predicting, and even permitting, the truth of the
5bs_bs_query conditional.
6bs_bs_query
7bs_bs_query 4.2. PREDICTING THE CONDITIONAL
8bs_bs_query
9bs_bs_query How do we predict the truth of a conditional like If you go to Aleppo, you
10bs_bs_query should not go to Aleppo? Obviously, the single-modal reading is not an
11 bs_bs_query option with the restrictor semantics: it’s predicted to be trivially false. So
12bs_bs_query let’s consider how we might find the double-modal reading. What values
13bs_bs_query for the contextual parameters can plausibly be projected from context to
14bs_bs_query predict the conditional?
15bs_bs_query Let A and D represent the propositions that Death goes to Aleppo
16bs_bs_query and that Death goes to Damascus, respectively; and let a and d represent
17bs_bs_query the propositions that you go to Aleppo and Damascus, respectively.
18bs_bs_query Again, the deontic domain is the area surrounded by the dashed
19bs_bs_query outline.
20bs_bs_query
21bs_bs_query 1. Suppose, naturally, that the deontic modal’s modal background
22bs_bs_query contains all four possibilities for where you and Death go: {Ad, Da,
23bs_bs_query Aa, Dd}. (See Figure 4.)
24bs_bs_query
25bs_bs_query Then the domain will include both kinds of worlds where you avoid
26bs_bs_query Death. Among these will be worlds where you go to Damascus and worlds
27bs_bs_query where you go to Aleppo. So it’s not the case that at that modal back-
28bs_bs_query ground you should not go to Aleppo (going is permissible). If you go to
29bs_bs_query Aleppo, you shouldn’t is therefore predicted to be false.
30bs_bs_query
31bs_bs_query Figure 4
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 20 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 5037DADD /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
20 PACIFIC PHILOSOPHICAL QUARTERLY
1bs_bs_query 2. Suppose the restriction from the if-clause is inherited by both the
2bs_bs_query epistemic and the deontic modal. The deontic modal’s modal back-
3bs_bs_query ground includes only {Aa, Da}. (See Figure 5.)
4bs_bs_query
5bs_bs_query Then the domain includes only worlds where you go to Aleppo. So the
6bs_bs_query conditional if you go to Aleppo, you shouldn’t is predicted to be false;
7bs_bs_query indeed, on this reading, if you go to Aleppo, you should is predicted to be
8bs_bs_query true.
9bs_bs_query
10bs_bs_query 3. Suppose the deontic modal’s modal background, by (ad hoc?) stipu-
11 bs_bs_query lation, contains only worlds where Death goes to Aleppo: {Aa, Ad}.
12bs_bs_query (See Figure 6.) Then the best worlds are worlds where you don’t go
13bs_bs_query to Aleppo. So we can get the prediction that If you go to Aleppo, you
14bs_bs_query shouldn’t is true.
15bs_bs_query
16bs_bs_query There are two problems with this way of fixing the contextual parame-
17bs_bs_query ters. First: what is the justification for holding Death’s location fixed
18bs_bs_query throughout the modal background? Presumably the information that
19bs_bs_query Death will be in Aleppo is an inference from (a) the information from the
20bs_bs_query antecedent that you will go to Aleppo and (b) the background information
21bs_bs_query that Death will be where you are. But while the modal background reflects
22bs_bs_query the conclusion from these two premises, it doesn’t reflect the premises
23bs_bs_query
24bs_bs_query Figure 5
25bs_bs_query
26bs_bs_query Figure 6
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 21 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 473C9519 /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
THE IF P, OUGHT P PROBLEM 21
1bs_bs_query themselves: the modal background doesn’t reflect premise (b). It allows
2bs_bs_query that you might be in a different place from Death, since it includes both
3bs_bs_query Aa-worlds and Ad-worlds.
4bs_bs_query In other words, speakers must assume in the very same breath that Death
5bs_bs_query must be in the same place as you and that he might not be. How is it
6bs_bs_query possible for context to fix the sets of relevant circumstances in this
7bs_bs_query way? It’s not just that the stipulation of the modal background is ad hoc:
8bs_bs_query it’s not clear that this is even a coherent configuration of background
9bs_bs_query assumptions.
10bs_bs_query A second and graver problem: there is a reading of (25a) and (25c)
11 bs_bs_query according to which both can be true. Let (25a) and (25c) be true at a point
12bs_bs_query of evaluation 〈w, f, g〉. Then the deontic modal’s domain at 〈w, f, g〉
13bs_bs_query contains both a-worlds and d-worlds.
14bs_bs_query Now assume (25a)’s modal background and domain are as represented
15bs_bs_query in Figure 6. Then relative to 〈w, f, g〉, every epistemically possible a-point
16bs_bs_query has a deontic domain that includes only d-worlds (since the domain in
17bs_bs_query Figure 6 entails Ad). Therefore at all epistemically possible a-worlds, the
18bs_bs_query deontic domain does not equal the deontic domain of 〈w, f, g〉. Therefore
19bs_bs_query the actual point of evaluation can’t be an a-point.
20bs_bs_query But we could run the same with (25b):
21bs_bs_query
22bs_bs_query (25b) If you stay in Damascus, you shouldn’t stay in Damascus.
23bs_bs_query
24bs_bs_query So all the epistemically possible points will have a different deontic domain
25bs_bs_query from the deontic domain at the actual point of evaluation. It follows that
26bs_bs_query the world of evaluation can’t be among the epistemically possible worlds.
27bs_bs_query In other words, from the point of view of the speaker, the actual world
28bs_bs_query won’t be epistemically possible.
29bs_bs_query This problem will afflict any stipulation of modal background and
30bs_bs_query ordering source we could use to predict (25a). And so with this kind of
31bs_bs_query semantics for iffy oughts, there’s no good way to predict the mutual truth
32bs_bs_query of the sentences in (25) without treating them as equivocal.
33bs_bs_query But these sentences should be compatible at a single context. They are
34bs_bs_query all the deliverances of a unified and coherent body of norms: namely,
35bs_bs_query causal decision theory plus the desire to avoid death.
36bs_bs_query
37bs_bs_query 5. A hypothesis
38bs_bs_query
39bs_bs_query To account for the consistency of the sentences in (25), it’s helpful to see
40bs_bs_query how other formal systems predict their mutual consistency.
41bs_bs_query First, note that the evidential expected utility of not going to Aleppo,
42bs_bs_query given that you go to Aleppo, is not defined. It would have to be calculated
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 22 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 55888B58 /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
22 PACIFIC PHILOSOPHICAL QUARTERLY
1bs_bs_query with Pr(A | a ∧ ¬a), which is undefined because Pr(a ∧ ¬a) is 0. But the
2bs_bs_query causal expected utility of not going to Aleppo, given that you go to
3bs_bs_query Aleppo, is defined.
4bs_bs_query For simplicity, we’ll use a simple causal decision theory that uses (non-
5bs_bs_query backtracking) counterfactuals: the causal expected utility of an act X is
6bs_bs_query Pr(X □→ S)U(XS) for all possible states S.
7bs_bs_query Suppose Pr(A | a) = Pr(D | d) = .99. Assume, as the example stated, that
8bs_bs_query your acts do not cause any of Death’s acts; he’s merely a very good
9bs_bs_query predictor of your actions. So Pr(a □→ A) = Pr(d □→ A) = Pr(A) and Pr(a
10bs_bs_query □→ D) = Pr(d □→ D) = Pr(D). The decision problem simplifies to:
11 bs_bs_query
12bs_bs_query DA
13bs_bs_query d −100 0
14bs_bs_query a 0 −100
15bs_bs_query
16bs_bs_query We are interested, not in each act’s expected utility simpliciter, but in its
17bs_bs_query expected utilities conditional on your going to Aleppo.
18bs_bs_query
19bs_bs_query EU(|) d a= Pr ( d!!→ A |)( a U Ad )+ Pr ( d→ D |)( a U Dd )
20bs_bs_query = −1 21bs_bs_query
22bs_bs_query
23bs_bs_query EU(|) a a= Pr ( a!!→ A |)( a U Aa )+ Pr ( a→ D |)( a U Da )
24bs_bs_query = −99 25bs_bs_query
26bs_bs_query
27bs_bs_query So given that you go to Aleppo, not going to Aleppo has much higher
28bs_bs_query causal expected utility. That’s why (25a) can be used to express a result of
29bs_bs_query causal decision theory:
30bs_bs_query
31bs_bs_query (25a) If you go to Aleppo, you should not go to Aleppo.
32bs_bs_query
33bs_bs_query Causal utility theory can be used to calculate the expected utility of an
34bs_bs_query act conditional on your performing another, incompatible act because it
35bs_bs_query separates two roles for acts. One role is the efficiently producing an
36bs_bs_query outcome. Another is simply as information about the how the world is: it’s
37bs_bs_query a world where a particular act is performed. Just as we can calculate the
38bs_bs_query expected utility of going to Aleppo conditional on its being sunny, so we
39bs_bs_query can calculate the expected utility of going to Aleppo conditional on your
40bs_bs_query not going to Aleppo.
41bs_bs_query If we want to allow that (25a), (25b), and (25c) can all be true without
42bs_bs_query equivocation between them – that is, without changes in the contextually
43bs_bs_query salient features, such as information and priorities – then I think we should
44bs_bs_query generalize this lesson. We can separate the two different roles of the
45bs_bs_query information in the if-clause:
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 23 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 54A794F1 /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
THE IF P, OUGHT P PROBLEM 23
1bs_bs_query 1. the role of (at least potentially) changing which actions are avail-
2bs_bs_query able, and;
3bs_bs_query 2. the role of (at least potentially) changing which actions are better
4bs_bs_query than which.
5bs_bs_query
6bs_bs_query Restricting the modal background takes care of the first role, while
7bs_bs_query updating the probability function takes care of the second.
8bs_bs_query Kratzer semantics for modals says that information can affect what
9bs_bs_query possibilities are available, by restricting the modal background. More 25 10bs_bs_query recently, Kolodny and MacFarlane (2010) and others have argued that
11 bs_bs_query information can affect not only what possibilities are available, but also
12bs_bs_query which possibilities are better than which, by affecting the deontic ordering.
13bs_bs_query Examples like the Death in Damascus case show that information can
14bs_bs_query affect availability and ideality independently of each other. In other words,
15bs_bs_query information can change which relevant worlds are better without changing
16bs_bs_query which worlds are available (and, of course, vice versa). They also show
17bs_bs_query that we need these distinct roles represented distinctly in the semantics for 26 18bs_bs_query deontic modals – i.e. two different informational parameters.
19bs_bs_query The minimal generalization of Kratzer semantics that accomplishes this
20bs_bs_query makes the ordering g a function of an information parameter. Instead of
21bs_bs_query g providing an ordering, g is a function from a deontic information input
22bs_bs_query to an ordering. In addition to the informational background f, which
23bs_bs_query provides information about which worlds are available, we add a deontic
24bs_bs_query information input parameter i, which is an input to g. Kratzer semantics is
25bs_bs_query recoverable within this framework: wherever Kratzer semantics correctly
26bs_bs_query predicts a particular ordering, the framework allows g to be a constant
27bs_bs_query function from i to the relevant ordering.
28bs_bs_query
29bs_bs_query DOMAINS: domain(w, f, g, i) is the set of worlds in the modal back-
30bs_bs_query ground f ranked highest by the ordering g(i).
31bs_bs_query MODALS: ought p is true at 〈w, f, g, i〉 iff p is true at all w′∈domain(w,
32bs_bs_query f, g, i).
33bs_bs_query
34bs_bs_query The simplest assumption is that, with unrestricted modals, f = i. But we
35bs_bs_query need not make this assumption. f might represent circumstantial informa-
36bs_bs_query tion, e.g. the set of worlds compatible with what the agent can do. i might
37bs_bs_query represent epistemic possibilities. We can remain neutral about how to
38bs_bs_query model i: it might be a set of worlds, or a probability function, or something
39bs_bs_query else.
40bs_bs_query In conditionals, the revision is more interesting. There are two basic
41bs_bs_query strategies we might pursue for putting our extra parameter to work in
42bs_bs_query cases like Death in Damascus.
43bs_bs_query
44bs_bs_query 1. Single-modal hypothesis: the conditional only has a deontic modal.
45bs_bs_query The if-clause updates the i parameter that provides the input to the
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 24 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 464C06D9 /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
24 PACIFIC PHILOSOPHICAL QUARTERLY
1bs_bs_query prioritizing parameter g. But the antecedent doesn’t necessarily
2bs_bs_query update the f. That is, in some cases it doesn’t as a restrictor for a
3bs_bs_query quantifier.
4bs_bs_query
5bs_bs_query So in (25a), the information that you’ll go to Aleppo updates i, the infor-
6bs_bs_query mation that affects what’s best. This information alters the ordering such
7bs_bs_query that worlds where you don’t go to Aleppo are highest ranked within the
8bs_bs_query unrestricted modal background f.
9bs_bs_query This strategy would generate an alternative to the restrictor analysis of
10bs_bs_query conditionals. Benefits: we can explain self-frustrating iffy oughts while
11 bs_bs_query retaining quasi-MT (and, if we want to, DIVERSITY). We also don’t
12bs_bs_query make our semantics rule out expressing the norms of causal decision
13bs_bs_query theory. Costs: we have to give up the restrictor analysis of conditionals, at
14bs_bs_query least in its full generality. We also have to generate a means of predicting
15bs_bs_query when antecedent information will restrict the modal background f and
16bs_bs_query when it will not. These costs are substantial.
17bs_bs_query
18bs_bs_query 2. Double-modal hypothesis: A very similar option that retains the
19bs_bs_query restrictor analysis: the if-clause on a self-frustrating iffy ought
20bs_bs_query restricts the modal background of covert modal but not the overt
21bs_bs_query modal embedded under it; but the if-clause also updates i for the
22bs_bs_query deontic modal.
23bs_bs_query
24bs_bs_query This strategy leaves us with all the benefits of the single-modal hypothesis
25bs_bs_query with one exception: quasi-MT is no longer valid.
26bs_bs_query Of the two options, the second is more conservative and doesn’t require
27bs_bs_query updating the traditional story about how to predict ordinary single-modal
28bs_bs_query iffy oughts. That is a point in its favor.
29bs_bs_query Let’s take on board the assumption of a single-/double-modal ambigu-
30bs_bs_query ity. The single-modal case will be probably be uninteresting: the informa-
31bs_bs_query tion from the antecedent will update the both f and i. (What precisely this
32bs_bs_query update amounts to in the case of i is left unspecified: if it’s a set of worlds,
33bs_bs_query presumably set intersection; if a probability function, it could be 27 34bs_bs_query conditionalization, imaging, etc.)
35bs_bs_query
36bs_bs_query CONDITIONALS (overt modal restricted):
37bs_bs_query if p, ought q is true at 〈w, f, g, i〉 iff q is true at domain(w, f + p, g, i + p)
38bs_bs_query
39bs_bs_query The double-modal case is more complex. In order to include modal
40bs_bs_query backgrounds and orderings for both the covert epistemic modal and
41bs_bs_query the overt deontic modal, the contextual parameters have to get more
42bs_bs_query complex. I subscript deontic parameters with d and epistemic parameters
43bs_bs_query with e.
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 25 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 53C5558A /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
THE IF P, OUGHT P PROBLEM 25
1bs_bs_query Here the if-clause information plays two roles:
2bs_bs_query
3bs_bs_query 1. It restricts the epistemic modal’s modal background fe.
4bs_bs_query 2. It updates the information input i for the deontic modal. (It does not
5bs_bs_query restrict the deontic modal’s modal background.)
6bs_bs_query
7bs_bs_query CONDITIONALS (covert modal restricted):
8bs_bs_query if p, (muste) oughtd q is true at 〈w, fe,fd,ge,gd,i〉 iff for all w ∈ domain(w,
9bs_bs_query fe + p, ge,i+ p), for all w′∈domain(w′,fd,gd,i+ p), q is true.
10bs_bs_query
11 bs_bs_query So, for example, in the case of (25a), we look at all epistemically possible
12bs_bs_query a-worlds, and check whether at each, the highest g(i + a)-ranked worlds
13bs_bs_query that are compatible with the agent’s capacities (fd, including both a-worlds
14bs_bs_query and d-worlds) are all worlds where the agent doesn’t go to Aleppo. g(i + a)
15bs_bs_query might be, for example, a ranking of worlds in terms of causal expected
16bs_bs_query utility, whether the expectation is determined by salient information
17bs_bs_query updated with the information that the agent goes to Aleppo. The highest
18bs_bs_query ranked worlds relative to these parameters, as we saw, were all worlds 28 19bs_bs_query where the agent does not go to Aleppo.
20bs_bs_query This provides a minimal generalization of Kratzer semantics plus the
21bs_bs_query single-/double modal ambiguity that allows the two roles for information
22bs_bs_query in deontic modals to vary independently of each other. Note that while this
23bs_bs_query semantics for the double-modal conditionals allows the deontic modal to
24bs_bs_query be sensitive to the antecedent’s information – because i is updated with the
25bs_bs_query antecedent’s information – this need not make a difference. In many 29 26bs_bs_query contexts, the salient priorities are not information-sensitive.
27bs_bs_query
28bs_bs_query 6. Conclusion
29bs_bs_query
30bs_bs_query I have argued that the if p, ought p puzzle causes deeper problems than
31bs_bs_query previously realized. Kratzer semantics for conditionals in its current form
32bs_bs_query can’t predict or model the data. What the if p, ought p problem reveals is
33bs_bs_query more general. First, there is an ambiguity between two forms of iffy ought:
34bs_bs_query those that express conditional obligations and those that express specula-
35bs_bs_query tion about obligation. Second, deontic modals are information-sensitive in
36bs_bs_query two different ways: information can affect what possibilities are available
37bs_bs_query and how these possibilities are ranked. These two forms of information-
38bs_bs_query sensitivity can vary independently of each other. I have provided a gener-
39bs_bs_query alized possible worlds semantics that is flexible enough to accommodate
40bs_bs_query both of these facts.
41bs_bs_query
42bs_bs_query School of Philosophy, Religion, and History of Science
43bs_bs_query University of Leeds
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 26 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 86B3B5C4 /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
26 PACIFIC PHILOSOPHICAL QUARTERLY
1bs_bs_query NOTES 8 bs_bs_query
1 2bs_bs_query Kratzer, 1979, 1981, 1991, generalized from Lewis, 1975. 2 3bs_bs_query To avoid typesetting complications, I use italics as a notational variant of corner quotes. 3 4bs_bs_query This is meant to be an intuitive characterization of the two moving parts; I’m not
5bs_bs_query committing myself to a particular view about deontic modals needing a particular flavor of
6bs_bs_query modal background. The relevant circumstances may e.g. be epistemic. 4 7bs_bs_query Similarly for other necessity modals: must, have to, should, etc. The classic account
8bs_bs_query doesn’t distinguish between so-called ‘strong’ versus ‘weak’ necessity modals. While I suspect
9bs_bs_query there might be complex interactions between the strong/weak necessity modal distinction and
10bs_bs_query the linguistic phenomena I discuss, they fall outside the scope of this article. 5 11 bs_bs_query A sociological note: throughout this article I use ‘ought’ as my canonical deontic
12bs_bs_query necessity modal. Among philosophers ought is commonly used in expressions of moral,
13bs_bs_query prudential, and rational necessity. (‘Ought implies can’; ‘subjective versus objective ought’;
14bs_bs_query ‘deriving an ought from an is’.) Nowadays ‘ought’ is typically not as natural in English
15bs_bs_query outside philosophy, and so the examples I use may be better expressed with ‘should’. 6 16bs_bs_query The preorder, in Kratzer semantics, is projected as follows: w > w′ – w is ‘more ideal’
17bs_bs_query than w′ – iff the set of ordering source propositions that w satisfies is a proper superset of the
18bs_bs_query set of ordering source propositions that w′ satisfies. Failures of trichotomy are irrelevant
19bs_bs_query for my discussion, so for expository and diagrammatic purposes, total orders are more
20bs_bs_query convenient. 7 21bs_bs_query My examples use epistemic must because epistemic ought introduces a confound: the
22bs_bs_query conditionals are sometimes judged infelicitous because, plausibly, epistemic ought generates
23bs_bs_query a scalar implicature that its prejacents epistemic standing is somehow shaky. The trivial
24bs_bs_query reading is easier to hear when the utterances include a sarcastic tone:
25bs_bs_query
26bs_bs_query (i) a. If it’s raining, it ought to be raining.
27bs_bs_query b. If it’s raining, it’s probably raining.
28bs_bs_query 8 29bs_bs_query Zvolenszky (2006) argues that the epistemic case is still problematic in some cases, with
30bs_bs_query the following example:
31bs_bs_query
32bs_bs_query (i) a. If this is the M3 motorway, then it must be the M3 motorway.
33bs_bs_query b. That is, If this is the M3, then I know that it is the M3.
34bs_bs_query
35bs_bs_query If I’m interpreting Zvolenszky correctly, she claims that (ia) is not trivial, on the grounds
36bs_bs_query that it can be glossed with (ib), which is obviously not trivial. I’m unconvinced that (ib) can
37bs_bs_query gloss (ia) – I can’t detect any such reading. Certainly this is not generally the case when the
38bs_bs_query contextually salient epistemic possibilities are compatible with the speaker’s knowledge. For
39bs_bs_query example:
40bs_bs_query
41bs_bs_query (ii) a. If the lights are out, she must not be home.
42bs_bs_query b. Not equivalent to: If the lights are out, then I know that she’s not home.
43bs_bs_query
44bs_bs_query See also further (more complex) evidence in Yalcin, 2007. 9 45bs_bs_query Thanks to Stephen Yablo for discussion. 10 46bs_bs_query Qualification: there are counterexamples where the antecedent intersected with the
47bs_bs_query modal background is empty; but otherwise this is universally true, and there are some reasons
48bs_bs_query to think that natural language modals are never evaluated at empty modal backgrounds. See
49bs_bs_query discussion of the diversity condition below.
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 27 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: 981F181C /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
THE IF P, OUGHT P PROBLEM 27
11 1bs_bs_query Of course, this could turn out to be a case of so-called non-catastrophic presupposition
2bs_bs_query failure, where sentences with presupposition failure are judged to be truth-evaluable: for
3bs_bs_query example, ‘The King of France is sitting on my lap.’ See Yablo, 2006. 12 4bs_bs_query It can also be generic, e.g. If Ryan gets home early, he drinks before dinner. 13 5bs_bs_query Alternatively, we might predict that iffy oughts are always doubly modalized, but the
6bs_bs_query if-clause can sometimes restrict both of the modals simultaneously. There is then an open
7bs_bs_query question of how to predict when the if-clause restricts only one. I’ll mostly ignore this
8bs_bs_query alternative, but it’s easy enough to generalize my discussion of the structural ambiguity
9bs_bs_query account to this variant model. 14 10bs_bs_query Note that the doubly modalized reading should sometimes be available even if the singly
11 bs_bs_query modalized reading is also available, as in Moss, 2005 manuscript, cited in von Fintel, 2011. 9 bs_bs_query 15 12bs_bs_query Mark Schroeder (pc) suggests that instead of suggesting that there’s no trivial reading of
13bs_bs_query if p, ought p, we can explain its apparent inaccessibility as an effect of its triviality. This may
14bs_bs_query be so. It’s worth noting, though, that trivial readings don’t usually disappear just because a
15bs_bs_query sentence has non-trivial disambiguations. For example: If there are cranes on the esplanade,
16bs_bs_query then there are cranes on the esplanade. 16 17bs_bs_query Kolodny and MacFarlane, 2010; Cariani, Kaufmann and Kaufmann, 2013; Charlow,
18bs_bs_query 2013; Carr, 2012; Silk, 2014. 17 19bs_bs_query Kolodny and MacFarlane attribute the case to Parfit (unpublished). 18 20bs_bs_query For defenses, again, see Kolodny and MacFarlane, 2010; Cariani, Kaufmann and
21bs_bs_query Kaufmann, 2013; Charlow, 2013; Carr, 2012; and Silk, 2014. For dissident voices, see
22bs_bs_query Dowell, 2013; Bronfmann and Dowell, forthcoming. 19 23bs_bs_query Assuming that epistemic modals are universal quantifiers over epistemically possible
24bs_bs_query worlds (i.e. that their ordering is trivial). 20 25bs_bs_query Kratzer semantics doesn’t validate modus tollens, and counterexamples in natural
26bs_bs_query language are easy enough to find. For example, gentle murderer cases: suppose at world w,
27bs_bs_query S will murder. The speaker need not know this. Suppose the contextually salient modal
28bs_bs_query background includes both murder- and not-murder-worlds, and all best worlds are not-
29bs_bs_query murder-worlds. When the modal background is restricted to the murder-worlds, the best
30bs_bs_query worlds in the restricted base are gentle-murder-worlds. Kratzer semantics says that at w,
31bs_bs_query relative to contextual parameters satisfying these constraints, the following three sentences
32bs_bs_query are all true:
33bs_bs_query
34bs_bs_query (i) a. S ought not murder gently (or otherwise).
35bs_bs_query b. If S will murder, S ought to murder gently.
36bs_bs_query c. S will murder.
37bs_bs_query
38bs_bs_query See e.g. Kolodny and MacFarlane, 2010 and Charlow, 2013. Note: if the speaker knows
39bs_bs_query S will murder, then in order for sentences to be consistent within Kratzer semantics, the
40bs_bs_query modal background can’t be the set of worlds compatible with the speaker’s knowledge. 21 41bs_bs_query By ‘respect’, I mean preserve acceptance: if the premises are accepted at a context, then
42bs_bs_query the conclusion must be accepted. (See e.g. Yalcin, 2007.) I use this notion as a means of
43bs_bs_query retaining neutrality between different conceptions of validity: acceptance preservation versus
44bs_bs_query truth preservation.
45bs_bs_query w,i 46bs_bs_query • p is accepted in an information state i iff ∀w ∈ i : [[p]] = 1.
47bs_bs_query • Consequence = acceptance preservation: p1,. . ., pn q iff every i that accepts p1,...,
48bs_bs_query pn accepts q. w,i 49bs_bs_query • [[□eq]] =1 iff i accepts q. w,i w,i 50bs_bs_query • [[if p, □eq]] = 1 iff i ∩ [[p]] accepts q.
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 28 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: B3BBBEEA /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
28 PACIFIC PHILOSOPHICAL QUARTERLY
1bs_bs_query So ¬q,(if p, □eq) ¬p. And then ¬□dq,(if p, □e□dq) ¬p. But this holds because of
2bs_bs_query epistemic modality’s special relation to acceptance preservation; the deontic modal has no
3bs_bs_query such relation. 22 4bs_bs_query Examples like this are discussed in a decision theoretic context in Gibbard and Harper,
5bs_bs_query 1978 and Hare and Hedden, 2012. 23 6bs_bs_query Allan Gibbard and William Harper (1978) discuss this story, putatively an ancient
7bs_bs_query Mesopotamian myth, in the context of decision theory; they cite Somerset Maugham’s
8bs_bs_query Sheppey (1934). 24 9bs_bs_query Throughout I’ll assume that the relevant kind of causal decision theory allows predic-
10bs_bs_query tions of this form even when the antecedent concerns the agent’s acts. 25 11 bs_bs_query Cariani, Kaufmann and Kaufmann, 2013; Charlow, 2013; Carr, 2012; Silk, 2014. 26 12bs_bs_query I briefly defend a view where there are two informational parameters in Carr, 2012. 27 13bs_bs_query It’s worth exploring whether it’s worthwhile to allow that in the single-modal case, i
14bs_bs_query doesn’t update with the antecedent information, but I won’t pursue this here. 28 15bs_bs_query Objection: If we’re assessing actions with probability zero, why not assess the value of
16bs_bs_query causing a miracle and killing Death? Reply: That option is not available at all in the modal
17bs_bs_query background. That’s why the modal background and deontic informational input are sepa-
18bs_bs_query rate. This isn’t stipulative: part of the purpose of a circumstantial modal background on a
19bs_bs_query deontic modal is to set aside actions that an agent is not able to perform. But in many
20bs_bs_query circumstances, even if you will p, you are able to not-p. (The fact that I will walk home
21bs_bs_query tonight doesn’t mean that I’m incapable of not walking home tonight.) So an antecedent you
22bs_bs_query p shouldn’t remove from the deontic modal background all ¬p possibilities. It might be that
23bs_bs_query I will do things I shouldn’t. 29 24bs_bs_query Distinguish information-sensitivity in contextual parameters from information-
25bs_bs_query sensitivity in norms. A non-information-sensitive priority parameter g is a constant function
26bs_bs_query from i to an ordering. Such a parameter might fully well capture the ranking of worlds
27bs_bs_query provided by information-sensitive norms. For example, there can be a constant function
28bs_bs_query from i to worlds where agents maximize expected utility relative to their own information, or
29bs_bs_query the speaker’s information (rather than the contextually salient information, i).
30bs_bs_query
31bs_bs_query REFERENCES
32bs_bs_query Bronfman, A. and Dowell, J. (forthcoming). ‘Contextualism about Deontic Conditionals,’ in
33bs_bs_query N. Charlow and M. Chrisman (eds) Deontic Modality. Oxford: Oxford University Press.
34bs_bs_query Cariani, F., Kaufmann, M. and Kaufmann, S. (2013). ‘Deliberative Modality under
35bs_bs_query Epistemic Uncertainty’, Linguistics and Philosophy, 36, pp. 225–259. 10 bs_bs_query
36bs_bs_query Carr, J. (2012). ‘Subjective “Ought”.’ Manuscript.
37bs_bs_query Charlow, N. (2013). ‘What We Know and What to Do.’ Synthese 190(12), pp. 2291–2323.
38bs_bs_query Dowell, J. (2013). ‘Flexible Contextualism about Deontic Modals: A Puzzle about
39bs_bs_query Information-sensitivity,’ Special issue of Inquiry devoted to Contextualism and Relativism
40bs_bs_query (H. Cappelen and S. Shapiro, eds), 56(2–3), pp.149–178.
41bs_bs_query Frank, A. (1997). Context Dependence in Modal Constructions. PhD thesis, Universität
42bs_bs_query Stuttgart.
43bs_bs_query van Fraassen, B. C. (1972). ‘The Logic of Conditional Obligation,’ Journal of Philosophical
44bs_bs_query Logic 1(3–4), pp. 417–438.
45bs_bs_query von Fintel, K. (2011). ‘Conditionals,’ in C. Maienborn, K. von Heusinger and P. Portner
46bs_bs_query (eds) Semantics: An International Handbook of Natural Language Meaning. Berlin: De
47bs_bs_query Gruyter Mouton.
48bs_bs_query Geurts, B. (2004). ‘On an Ambiguity in Quantified Conditionals.’ Manuscript.
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd. JOBNAME: No Job Name PAGE: 29 SESS: 66 OUTPUT: Mon Oct 6 17:21:13 2014 SUM: BC6367E2 /Xpp84/wiley_journal_P/PAPQ/papq_v0_i0/papq_12048
THE IF P, OUGHT P PROBLEM 29
1bs_bs_query Gibbard, A. and Harper, W. (1978). ‘Counterfactuals and Two Kinds of Expected Utility,’
2bs_bs_query in C. A. Hooker, J. J. Leach and E. F. McClennan (eds) Foundations and Applications of
3bs_bs_query Decision Theory. Dordrecht: D. Reidel, pp. 125–162.
4bs_bs_query Hare, C. and Hedden, B. (2012). ‘Self-Reinforcing and Self-Frustrating Decisions.’ Manu-
5bs_bs_query script.
6bs_bs_query Jackson, F. (1985). ‘On the Semantics and Logic of Obligation,’ Mind 94(374), pp. 177–195.
7bs_bs_query Kolodny, N. and MacFarlane, J. (2010). ‘Ifs and Oughts,’ Journal of Philosophy 107(3), pp.
8bs_bs_query 115–143.
9bs_bs_query Kratzer, A. (1981). ‘The Notional Category of Modality,’ in H-J. Eikmeyer and H. Rieser
10bs_bs_query (eds) Words, Worlds, and Contexts: New Approaches in World Semantics. Berlin: de
11 bs_bs_query Gruyter.
12bs_bs_query Kratzer, A. (1991). ‘Modality,’ in A. von Stechow and D. Wunderlich (eds) Semantics: An
13bs_bs_query International Handbook of Contemporary Research. Berlin: de Gruyter, pp. 639–650.
14bs_bs_query Kratzer, A. (2012). Modals and Conditionals. Oxford: Oxford University Press.
15bs_bs_query Maugham, S. (1934). Sheppey. New York: Doubleday.
16bs_bs_query Parfit, D. (unpublished). ‘What We Together Do.’
17bs_bs_query Prior, A. N. (1958). ‘Escapism: The Logical Basis of Ethics,’ in A. I. Melden (ed.) Essays in
18bs_bs_query Moral Philosophy. Seattle, WA: University of Washington Press, pp. 135–146.
19bs_bs_query Silk, A. (2014). ‘Evidence-Sensitivity in Weak Necessity Deontic Modals,’ Journal of Philo-
20bs_bs_query sophical Logic 43(4), pp. 691–723.
21bs_bs_query Spohn, W. (1975). ‘An Analysis of Hansson’s Dyadic Deontic Logic,’ Journal of Philosophi-
22bs_bs_query cal Logic 4(2), pp. 237–252.
23bs_bs_query Yablo, S. (2006). ‘Non-Catastrophic Presupposition Failure,’ in J. Thomson and A. Byrne
24bs_bs_query (eds) Themes from the Philosophy of Robert Stalnaker. Oxford: Oxford University Press,
25bs_bs_query pp. 164–190.
26bs_bs_query Yalcin, S. (2007). ‘Epistemic Modals,’ Mind 116(464), pp. 983–1026.
27bs_bs_query Zvolenszky, Z. (2002). ‘Is a Possible-Worlds Semantics of Modality Possible? A Problem for
28bs_bs_query Kratzer’s Semantics,’ in B. Jackson (ed.) Proceedings of Semantics and Linguistic Theory
29bs_bs_query 12 . Ithaca, NY: Cornell University Press, pp. 339–358
30bs_bs_query Zvolenszky, Z. (2006). ‘A Semantic Constraint on the Logic of Modal Conditionals,’ In B.
31bs_bs_query Gyuris, L. Kálmán, C. Pinon and K. Varasdi (eds) Proceedings of the Ninth Symposium on
32bs_bs_query Logic and Language (LoLa 9). Budapest: Eotvos Lorand University Press, pp. 167–177.
33bs_bs_query Zvolenszky, Z. (2007). ‘The Lost Pillar of Deontic Modality,’ Modality, Names and Descrip-
34bs_bs_query tions, PhD thesis, New York University.
© 2014 The Author Pacific Philosophical Quarterly © 2014 University of Southern California and John Wiley & Sons Ltd.