According to an influential recent view, S is propositionally justified in believing p iff S is in no position to know that S is in no position to know p. I argue that this view faces compelling counterexamples.

In a broad brush, biological models are often constructed in two general types: as a concrete model; as an abstract model. A concrete model is a material model such as model organisms, while an abstract model is a mathematical or computational model consists of equations or algorithms. Though there are types of biological models that cannot be strictly categorized as either concrete or abstract, they are falling somewhere in between this spectrum. In view of the fact that biological phenomena are (...) sui generis and distinct from physical phenomena in many respects, using the concepts in standard modeling fails to account for the differences between biological sciences and physical sciences. Drawing from the resources of a credible-world account of models in economic modeling, I propose to reinterpret abstract models and concrete models in the light of the credible world account of models. (shrink)

It has recently been argued that indeterminacy and indeterminism make most ordinary counterfactuals false. I argue that a plausible way to avoid such counterfactual skepticism is to postulate the existence of primitive modal facts that serve as truth-makers for counterfactual claims. Moreover, I defend a new theory of ‘might’ counterfactuals, and develop assertability and knowledge criteria to suit such unobservable ‘counterfacts’.

There seem to be two ways of supposing a proposition: supposing “indicatively” that Shakespeare didn’t write Hamlet, it is likely that someone else did; supposing “subjunctively” that Shakespeare hadn’t written Hamlet, it is likely that nobody would have written the play. Let P be the probability of B on the subjunctive supposition that A. Is P equal to the probability of the corresponding counterfactual, A □→B? I review recent triviality arguments against this hypothesis and argue that they do not succeed. (...) On the other hand, I argue that even if we can equate P with P, we still need an account of how subjunctive conditional probabilities are related to unconditional probabilities. The triviality arguments reveal that the connection is not as straightforward as one might have hoped. (shrink)

There is a renewed debate about modus ponens. Strikingly, the recent counterexamples in Cantwell, Dreier and MacFarlane and Kolodny are generated by restricted readings of the ‘if’-clause. Moreover, it can be argued on general grounds that the restrictor view of conditionals developed in Kratzer and Lewis leads to counterexamples to modus ponens. This paper provides a careful analysis of modus ponens within the framework of the restrictor view. Despite appearances to the contrary, there is a robust sense in which modus (...) ponens is valid, owing to the fact that conditionals do not only allow for restricted readings but have bare interpretations, too. (shrink)

On an influential line of thinking tracing back to Ramsey, conditionals are closely linked to the attitude of supposition. When applied to counterfactuals, this view suggests a subjunctive version of the so-called Ramsey test: the probability of a counterfactual If A, would B ought to be equivalent to the probability of B, under the subjunctive supposition that A. I present a collapse result for any view that endorses the subjunctive version of the Ramsey test. Starting from plausible assumptions, the result (...) shows that one’s rational credence in a would-counterfactual and in the corresponding might-counterfactual have to be identical. (shrink)

Given his hostility to intensional locutions, it is not surprising that Quine was suspicious of the subjunctive conditional. Although he admitted its usefulness as a heuristic device, in order to introduce dispositional terms, he held that it had no place in a finished scientific theory. In this paper I argue in support of something like Quine’s position. Many contemporary philosophers are unreflectively realist about subjunctives, regarding them as having objective truth values. I contest this. “Moderate realist” theorists, such as Lewis (...) and Stalnaker, admit that subjunctives are context-relative and often indeterminate; I argue, using some examples from the contemporary literature on conditionals, that these features are deeper and more widespread than they think. “Ultra-realist” theories, which deny any indeterminacy, are not credible. Hence subjunctives are unsuitable for certain purposes, in particular the description of mind-independent reality. (shrink)

Counterfactual scepticism holds that most ordinary counterfactuals are false. The main argument for this view appeals to a ‘chance undermines would’ principle: if ψ would have some chance of not obtaining had ϕ obtained, then ϕ □→ ψ is false. This principle seems to follow from two fairly weak principles, namely, that ‘chance ensures could’ and that ϕ □→ ψ and ϕ ⋄→ ¬ ψ clash. Despite their initial plausibility, I show that these principles are independently problematic: given some modest (...) closure principles, they entail absurdities. Moreover, on the most promising strategy for saving these principles, they do not, in the relevant sense, entail the chance-undermines-would principle. Instead, they entail a principle that only supports counterfactual indeterminism, the view that most ordinary counterfactuals are chancy, that is, not settled true. I demonstrate this by developing an indeterminist semantics that vindicates the clash and chance-ensures-could principles but not the chance-undermines-would principle. This view, I argue, offers a better account of our credal and linguistic judgements than counterfactual scepticism. (shrink)

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. (shrink)

This essay calls attention to a set of linguistic interactions between counterfactual conditionals, on one hand, and possibility modals like could have and might have, on the other. These data present a challenge to the popular variably strict semantics for counterfactual conditionals. Instead, they support a version of the strict conditional semantics in which counterfactuals and possibility modals share a unified quantificational domain. I’ll argue that pragmatic explanations of this evidence are not available to the variable analysis. And putative counterexamples (...) to the unified strict analysis, on careful inspection, in fact support it. Ultimately, the semantics of conditionals and modals must be linked together more closely than has sometimes been recognized, and a unified strict semantics for conditionals and modals is the only way to fully achieve this. (shrink)

Thought experiments invite us to evaluate philosophical theses by making judgements about hypothetical cases. When the judgements and the theses conflict, it is often the latter that are rejected. But what is the nature of the judgements such that they are able to play this role? I answer this question by arguing that typical judgements about thought experiments are in fact judgements of normal counterfactual sufficiency. I begin by focusing on Anna-Sara Malmgren’s defence of the claim that typical judgements about (...) thought experiments are mere possibility judgements. This view is shown to fail for two closely related reasons: it cannot account for the incorrectness of certain misjudgements, and it cannot account for the inconsistency of certain pairs of conflicting judgements. This prompts a reconsideration of Timothy Williamson’s alternative proposal, according to which typical judgements about thought experiments are counterfactual in nature. I show that taking such judgements to concern what would normally hold in instances of the relevant hypothetical scenarios avoids the objections that have been pressed against this kind of view. I then consider some other potential objections, but argue that they provide no grounds for doubt. (shrink)

Since our capacities and methods of cognizing reality merely seem to tell us how things are but only within close limits how they could or must be, our claims to knowledge of mere possibilities and necessities raise the suspicion of exceptionalism: the capacities and methods used in developing these claims seem special compared to those involved in cognizing reality. One may be sceptical especially with regard to them, and there are doubts that they can be naturalistically explained. To avoid exceptionalism, (...) Timothy Williamson has proposed to reduce the epistemology of modality to the epistemology of everyday counterfactuals. There are doubts that the proposal succeeds. One objection is that the counterfactual-based epistemology fails to account for metaphysical necessities like the necessity of origin. For the account to cover such necessities, constitutive facts like the origin of a living being would have to form implicit constraints built into the capacity for everyday counterfactual reasoning. But is counterfactual reasoning indeed so constrained? I answer this question in the affirmative, presenting an epistemology of counterfactuals for modal epistemology to build on. The constraints gradually emerge by a broadly abductive process, starting from within everyday counterfactual reasoning. The process does not presuppose any independent knowledge of the constitutive status of certain facts. (shrink)

The view that if-clauses function semantically as restrictors is widely regarded as the only candidate for a fully general account of conditionals. The standard implementation of this view assumes that, where no operator to be restricted is in sight, if-clauses restrict covert epistemic modals. Stipulating such modals, however, lacks independent motivation and leads to wrong empirical predictions. In this paper I provide a theory of conditionals on which if-clauses are uniformly interpreted as restrictors, but no covert modals are postulated. Epistemic (...) if-clauses, like those in bare conditionals, restrict an information state parameter which is used to interpret an expressive layer of the language. I show that this theory yields an attractive account of bare and overtly modalized conditionals and solves various empirical problems for the standard view, while dispensing with its less plausible assumption. (shrink)

Statements about the future are central in everyday conversation and reasoning. How should we understand their meaning? The received view among philosophers treats will as a tense: in ‘Cynthia will pass her exam’, will shifts the reference time forward. Linguists, however, have produced substantial evidence for the view that will is a modal, on a par with must and would. The different accounts are designed to satisfy different theoretical constraints, apparently pulling in opposite directions. We show that these constraints are (...) jointly satisfied by a novel modal account of will. On this account, will is a modal but doesn't work as a quantifier over worlds. Rather, the meaning of will involves a selection function similar to the one used by Stalnaker in his semantics for conditionals. The resulting theory yields a plausible semantics and logic for will and vindicates our intuitive views about the attitudes that rational agents should have towards future-directed contents. (shrink)

Provisional draft, pre-production copy of my book “The Modal Future” (forthcoming with Cambridge University Press).

In Counterfactual Conditionals, Daniel Dohrn discusses the standard account of counterfactuals, conditionals of the form ‘If A had been the case, then B would have been the case’. According to the standard account, a counterfactual is true if the then-sentence is true in all closest worlds in which the if-sentence is true. Closeness is spelled out in terms of an ordering of worlds by their similarity. Dohrn explores resources of defending the standard account against several challenges. In particular, he defends (...) the standard logics for counterfactuals. He discusses exemplary doubts as to whether conditionals have truth conditions. He inquires into the interaction between truth and probability of counterfactuals. He tackles problems with the similarity ordering. He address the interaction between counterfactuals and normalcy conditions. He closes with elaborating peculiarities of future-directed counterfactuals. (shrink)

The principle of Conditional Excluded Middle has been a matter of longstanding controversy in both semantics and metaphysics. According to this principle, we are, inter alia, committed to claims like the following: If the coin had been flipped, it would have landed heads, or if the coin had been flipped, it would not have landed heads. In favour of the principle, theorists have appealed, primarily, to linguistic data such as that we tend to hear ¬(A > B) as equivalent to (...) (A > ¬B). Williams (2010), provides one of the most compelling recent arguments along these lines by appealing to intuitive equivalencies between certain quantified conditional statements. We argue that the strategy Williams employs can be parodied to generate an argument for the unwelcome principle of Should Excluded Middle: the principle that, for any A, it either should be that A or it should be that not A. Uncovering what goes wrong with this argument casts doubt on a key premise in Williams’ argument. The way we develop this point is by defending the thesis that, like "should", "would" is a so-called neg-raising predicate. Neg-raising is the linguistic phenomenon whereby “I don’t think that Trump is a good president” strongly tends to implicate “I think that Trump is not a good president,” despite the former not semantically entailing the latter. We show how a defender of a Lewis-style semantics for counterfactuals should implement the idea that the counterfactual is a “neg-raiser”. (shrink)