Justin Khoo

I observe a range of cases in which it is possible to suspend belief about whether p and yet lack any degree of subjective uncertainty whether p. Each of these cases concerns a particular kind of predicate, which I call reactive, identified by their being felicitously embeddable under finds in the construction, S finds x R. I show how we can predict these otherwise puzzling observations within a semantic theory of reactive claims on which they are non-factual. I conjecture that non-factual claims only have probabilities when they are determined by probabilities about matters of fact; thus, in certain cases, non-factual claims can fail to be more or less likely true. Two upshots follow. First, it opens a new avenue for exploring how to integrate the language of subjective uncertainty with fine-grained semantic theories such as relativism and expressivism. Second, it suggests a new way to think about the relationship between fact-stating and non-fact stating domains of discourse: the possibility of indecision without uncertainty is a mark of the non-factual.

When we see a movie or a play, do we see the fictional entities and events depicted? On the one hand, it seems incredibly natural to think we do. For instance, it seems obvious that one thing that differentiates Smith, who watches Star Wars, from Bob, who merely reads the novelization of Star Wars, is that Smith, but not Bob, has seen Darth Vader kill Obi-Wan Kenobi. Yet, no philosophers working on fiction think this is literally true. And they have good reasons to be skeptical. For, if you have seen Darth Vader kill Obi-Wan Kenobi, then it seems to follow that Darth Vader must have killed Obi-Wan Kenobi, in which case, it follows that both were at one point living, flesh-and-blood, entities. But if Darth Vader is a flesh and blood being, then he must be spatiotemporally located, in which case, where is he? In this paper, I argue that we do in fact literally see (and hear) fictional entities when we see films. I do so in three stages. First, I argue against various error theories that attempt to account for the intuitions that we do see fictional entities in film. Then, I sketch a metaphysics of fictional entities, which vindicates our genuinely seeing them. Finally, I explore some of the interesting controversies and objections raised to this ontology of the fictional.

Accounting for the behavior of conjoined and disjoined if-clauses is not easy for standard theories of conditionals that treat if as either an operator or restrictor. In this paper, I discuss four observations about coordinated if-clauses, and motivate a semantics for conditionals that reorients the compositional structure of the restrictor theory. On my proposal, if-clauses provide restrictions on modal domains, but they do so by way of a higher type intermediary—a set of propositions—that is collapsed by the modal. I argue that combining this view with an independently plausible type-shifting operation applied to or and and predicts the range of data we find for conditionals with coordinated if-clauses.

When we see a movie or a play, do we see the fictional entities and events depicted? On the one hand, it seems incredibly natural to think we do. For instance, it seems obvious that one thing that differentiates Smith, who watches Star Wars, from Bob, who merely reads the novelization of Star Wars, is that Smith, but not Bob, has seen Darth Vader kill Obi‐Wan Kenobi. Yet, no philosophers working on fiction think this is literally true. And they have good reasons to be skeptical. For, if you have seen Darth Vader kill Obi‐Wan Kenobi, then it seems to follow that Darth Vader must have killed Obi‐Wan Kenobi, in which case, it follows that both were at one point living, flesh‐and‐blood, entities. But if Darth Vader is a flesh and blood being, then he must be spatiotemporally located, in which case, where is he? In this paper, I argue that we do in fact literally see (and hear) fictional entities when we see films. I do so in three stages. First, I argue against various error theories that attempt to account for the intuitions that we do see fictional entities in film. Then, I sketch a metaphysics of fictional entities, which vindicates our genuinely seeing them. Finally, I explore some of the interesting controversies and objections raised to this ontology of the fictional.

Suppose I hear from a trusted friend that The Shining is scary. Believing them, I decide not to watch the film. Later, we're talking about the movie and I say, “The Shining is scary!” My assertion here is misleading and inappropriate—I misrepresent myself as having seen the film and judged whether it is scary. But why is this? In this paper, I clarify the scope of the observation, discuss existing explanations of it, and argue that they are all lacking. I argue that the observation is best explained as a particular instance of a general norm which holds that authorities should make assertions about matters in their authority only if they have judged those matters for themselves. Along the way, I offer a theory of judgment which distinguishes it from mere belief.

This Handbook brings together philosophical work on how language shapes, and is shaped by, social and political factors. Its 24 chapters were written exclusively for this volume by an international team of leading researchers, and together they provide a broad expert introduction to the major issues currently under discussion in this area. The volume is divided into four parts: Part I: Methodological and Foundational Issues Part II: Non-ideal Semantics and Pragmatics Part III: Linguistic Harms Part IV: Applications The parts, and chapters in each part, are introduced in the volume's General Introduction. A list of Works Cited concludes each chapter, pointing readers to further areas of study. The Handbook is the first major, multi-authored reference work in this growing area and essential reading for anyone interested in the nature of language and its relationship to social and political reality.

Epistemicists claim that vague predicates have precise but unknow- able cutoffs. I argue against against the standard, Williamsonian, answer, that appeals to metalinguistic safety: we can know that p even if our true belief that p is metalinguistically lucky. I then propose that epistemicists should be diagonalized epistemicists and show how this alternative formulation of the view avoids the chal- lenge. However, in an M. Night Shyamalan-style twist, I then argue we should not be diagonalized epistemicists either.

Despite its small stature, "if" occupies a central place both in everyday language and the philosophical lexicon. In allowing us to talk about hypothetical situations, "if" raises a host of thorny philosophical puzzles about language and logic. Addressing them requires tools from linguistics, logic, probability theory, and metaphysics. Justin Khoo uses these tools to navigate a maze of interconnected issues about conditionals, some of which include: the nature of linguistic communication, the relationship between logical and natural languages, and the relationship between different kinds of modality. According to Khoo's theory, conditionals form a unified class of expressions which share a common semantic core that encodes inferential dispositions. Thus, rather than represent the world, conditionals are devices used to communicate how we are disposed to infer. Khoo shows that this theory can be extended to predict the probabilities of conditionals, as well as how different kinds of conditionals differ both semantically and pragmatically. Khoo's book will make for a significant contribution to the literature on conditionals and should be of interest to philosophers, linguists, and computer scientists.

A middle fact is a true proposition about what would have happened had A been true (where A is in fact false), whose truth isn't entailed by any non-counterfactual facts. I argue that there are no middle facts; if there were, we wouldn't know them, and our ignorance of them would result in ignorance about whether regret is fitting in cases where we clearly know it is. But there's a problem. Consider an unflipped fair coin which is such that no non-counterfactual fact determines that it would have landed heads had it been flipped (or tails had it been flipped). If there are no middle facts, it's not true that it would have landed heads had it been flipped nor that it would have landed tails had it been flipped. Yet each counterfactual is still possibly true for all we know. I argue that we can resolve this tension in the anti-middle fact position, further strengthening the case against middle facts.

Disjunctive antecedent conditionals —conditionals of the form if A or B, C—sometimes seem to entail both of their simplifications and sometimes seem not to. I argue that this behavior reveals a genuine ambiguity in DACs. Along the way, I discuss a new observation about the role of focal stress in distinguishing the two interpretations of DACs. I propose a new theory, according to which the surface form of a DAC underdetermines its logical form: on one possible logical form, if A or B, C does entail both of its simplifications, while on the other, it does not.

ABSTRACTRecent debate over the semantics and pragmatics of epistemic modals has focused on intuitions about cross-contextual truth-value assessments. In this paper, we advocate a different approach to evaluating theories of epistemic modals. Our strategy focuses on judgments of the incompatibility of two different epistemic possibility claims, or two different truth value assessments of a single epistemic possibility claim. We subject the predictions of existing theories to empirical scrutiny, and argue that existing contextualist and relativist theories are unable to account for the full pattern of observed judgments. As a way of illustrating the theoretical upshot of these results, we conclude by developing a novel theory of epistemic modals that is able to predict the results.

When speakers utter conflicting moral sentences, it seems clear that they disagree. It has often been suggested that the fact that the speakers disagree gives us evidence for a claim about the semantics of the sentences they are uttering. Specifically, it has been suggested that the existence of the disagreement gives us reason to infer that there must be an incompatibility between the contents of these sentences. This inference then plays a key role in a now-standard argument against certain theories in moral semantics. In this paper, we introduce new evidence that bears on this debate. We show that there are moral conflict cases in which people are inclined to say both that the two speakers disagree and that it is not the case at least one of them must be saying something incorrect. We then explore how we might understand such disagreements. As a proof of concept, we sketch an account of the concept of disagreement and an independently motivated theory of moral semantics which, together, explain the possibility of such cases.

I argue that not all context dependent expressions are alike. Pure (or ordinary) indexicals behave more or less as Kaplan thought. But quasi indexicals behave in some ways like indexicals and in other ways not like indexicals. A quasi indexical sentence φ allows for cases in which one party utters φ and the other its negation, and neither party’s claim has to be false. In this sense, quasi indexicals are like pure indexicals (think: “I am a doctor”/“I am not a doctor” as uttered by different individuals). In such cases involving a pure indexical sentence, it is not appropriate for the two parties to reject each other’s claims by saying, “No.” However, in such cases involving a quasi indexical sentence, it is appropriate for the par- ties to reject each other’s claims. In this sense, quasi indexicals are not like pure indexicals. Drawing on experimental evidence, I argue that gradable adjectives like “rich” are quasi indexicals in this sense. e existence of quasi indexicals raises trouble for many existing theories of context dependence, including standard contextualist and relativist theories. I propose an alternative semantic and pragmatic theory of quasi indexicals, negotiated contextualism, that combines insights from Kaplan 1989 and Lewis 1979. On my theory, rejection is licensed with quasi indexicals (even when neither of the claims involved has to be false) because the two utterances involve conflicting proposals about how to update the conversational score. I also adduce evidence that conflicting truth value assessments of a single quasi indexical utterance exhibit the same behavior. I argue that negotiated contextualism can account for this puzzling property of quasi indexicals as well.

Inquiry into the meaning of logical terms in natural language (‘and’, ‘or’, ‘not’, ‘if’) has generally proceeded along two dimensions. On the one hand, semantic theories aim to predict native speaker intuitions about the natural language sentences involving those logical terms. On the other hand, logical theories explore the formal properties of the translations of those terms into formal languages. Sometimes, these two lines of inquiry appear to be in tension: for instance, our best logical investigation into conditional connectives may show that there is no conditional operator that has all the properties native speaker intuitions suggest if has. Indicative conditionals have famously been the source of one such tension, ever since the triviality proofs of both Lewis (1976) and Gibbard (1981) established conclusions which are in prima facie tension with ordinary judgments about natural language indicative conditionals. In a recent series of papers, Branden Fitelson has strengthened both triviality results (Fitelson 2013, 2015, 2016), revealing a common culprit: a logical schema known as IMPORT-EXPORT. Fitelson’s results focus the tension between the logical results and ordinary judgments, since IMPORT-EXPORT seems to be supported by intuitions about natural language. In this paper, we argue that the intuitions which have been taken to support IMPORT-EXPORT are really evidence for a closely related, but subtly different, principle. We show that the two principles are independent by showing how, given a standard assumption about the conditional operator in the formal language in which IMPORT-EXPORT is stated, many existing theories of indicative conditionals validate one, but not the other. Moreover, we argue that once we clearly distinguish these principles, we can use propositional anaphora to show that IMPORT-EXPORT is in fact not valid for natural language indicative conditionals (given this assumption about the formal conditional operator). This gives us a principled and independently motivated way of rejecting a crucial premise in many triviality results, while still making sense of the speaker intuitions which appeared to motivate that premise. We suggest that this strategy has broad application and an important lesson: in theorizing about the logic of natural language, we must pay careful attention to the translation between the formal languages in which logical results are typically proved, and natural languages which are the subject matter of semantic theory.

According to operator theories, "if" denotes a two-place operator. According to restrictor theories, "if" doesn't contribute an operator of its own but instead merely restricts the domain of some co-occurring quantifier. The standard arguments (Lewis 1975, Kratzer 1986) for restrictor theories have it that operator theories (but not restrictor theories) struggle to predict the truth conditions of quantified conditionals like (1) a. If John didn't work at home, he usually worked in his office. b. If John didn't work at home, he must have worked in his office. Gillies (2010) offers a context-shifty conditional operator theory that predicts the right truth conditions for epistemically modalized conditionals like (1b), thus undercutting one standard argument for restrictor theories. I explore how we might generalize Gillies' theory to adverbially quantified conditionals like (1a) and deontic conditionals, and argue that a natural generalization of Gillies' theory -- following his strategy for handling epistemically modalized conditionals -- won't work for these other conditionals because a crucial assumption that epistemic modal bases are closed (used to neutralize the epistemic quantification contributed by "if") doesn't have plausible analogs in these other domains.

The Ramseyan thesis that the probability of an indicative conditional is equal to the corresponding conditional probability of its consequent given its antecedent is both widely confirmed and subject to attested counterexamples (e.g., McGee 2000, Kaufmann 2004). This raises several puzzling questions. For instance, why are there interpretations of conditionals that violate this Ramseyan thesis in certain contexts, and why are they otherwise very rare? In this paper, I raise some challenges to Stefan Kaufmann's account of why the Ramseyan thesis sometimes fails, and motivate my own theory. On my theory, the proposition expressed by an indicative conditional is partially determined by a background partition, and hence its probability depends on the choice of such a partition. I hold that this background partition is contextually determined, and in certain conditions is set by a salient question under discussion in the context. I show how the resulting theory offers compelling answers to the puzzling questions raised by failures of the Ramseyan thesis.

At the center of the literature on conditionals lies the division between indicative and subjunctive conditionals, and Ernest Adams’ famous minimal pair: If Oswald didn’t shoot Kennedy, someone else did. If Oswald hadn’t shot Kennedy, someone else would have. While a lot of attention is paid to figuring out what these different kinds of conditionals mean, significantly less attention has been paid to the question of why their grammatical differences give rise to their semantic differences. In this paper, I articulate and defend an answer to this question that illuminates and unifies the meanings of both kinds of conditionals. The basic idea is that epistemic and metaphysical possibilities differ with respect to their interaction with time, such that there can be present epistemic possibilities with different pasts, while present metaphysical possibilities share the same past. The interpretation of conditionals is subject to a pragmatic constraint that rules out interpretations in which their consequents are directly settled by information used to build their domains. The past + future morphology on subjunctives, but not indicatives, is what allows them to receive a metaphysical interpretation in light of this pragmatic constraint. The resulting theory predicts several surprising features of indicatives and subjunctives, which I argue are correct

This paper discusses and relates two puzzles for indicative conditionals: a puzzle about indeterminacy and a puzzle about triviality. Both puzzles arise because of Ramsey's Observation, which states that the probability of a conditional is equal to the conditional probability of its consequent given its antecedent. The puzzle of indeterminacy is the problem of reconciling this fact about conditionals with the fact that they seem to lack truth values at worlds where their antecedents are false. The puzzle of triviality is the problem of reconciling Ramsey's Observation with various triviality proofs which establish that Ramsey's Observation cannot hold in full generality. In the paper, I argue for a solution to the indeterminacy puzzle and then apply the resulting theory to the triviality puzzle. On the theory I defend, the truth conditions of indicative conditionals are highly context dependent and such that an indicative conditional may be indeterminate in truth value at each possible world throughout some region of logical space and yet still have a nonzero probability throughout that region.

A proof by Allan Gibbard (Ifs: Conditionals, beliefs, decision, chance, time. Reidel, Dordrecht, 1981) seems to demonstrate that if indicative conditionals have truth conditions, they cannot be stronger than material implication. Angelika Kratzer's theory that conditionals do not denote two-place operators purports to escape this result [see Kratzer (Chic Linguist Soc 22(2):1–15, 1986, 2012)]. In this note, I raise some trouble for Kratzer’s proposed method of escape and then show that her semantics avoids this consequence of Gibbard’s proof by denying modus ponens. I also show that the same holds for Anthony Gillies’ semantics (Philos Rev 118(3):325–349, 2009) and argue that this consequence of these theories is not obviously prohibitive—hence, both remain viable theories of indicative conditionals