The traditional Bayesian qualitative account of evidential support (TB) takes assertions of the form 'E evidentially supports H' to affirm the existence of a two-place relation of evidential support between E and H. The analysans given for this relation is $C(H,E) =_{def} Pr(H\arrowvertE) \models Pr(H)$ . Now it is well known that when a hypothesis H entails evidence E, not only is it the case that C(H,E), but it is also the case that C(H&X,E) for any arbitrary X. There is (...) a widespread feeling that this is a problematic result for TB. Indeed, there are a number of cases in which many feel it is false to assert 'E evidentially supports H&X', despite H entailing E. This is known, by those who share that feeling, as the 'tacking problem' for Bayesian confirmation theory. After outlining a generalization of the problem, I argue that the Bayesian response has so far been unsatisfactory. I then argue the following: (i) There exists, either instead of, or in addition to, a two-place relation of confirmation, a three-place, 'contrastive' relation of confirmation, holding between an item of evidence E and two competing hypotheses H₁ and H₂. (ii) The correct analysans of the relation is a particular probabilistic inequality, abbreviated C(H₁, H₂, E). (iii) Those who take the putative counterexamples to TB discussed to indeed be counterexamples are interpreting the relevant utterances as implicitly contrastive, contrasting the relevant hypothesis H₁ with a particular competitor H₂. (iv) The probabilistic structure of these cases is such that ∼C(H₁, H₂, E). This solves my generalization of the tacking problem. I then conclude with some thoughts about the relationship between the traditional Bayesian account of evidential support and my proposed account of the three-place relation of confirmation. (shrink)

I outline four competing probabilistic accounts of contrastive evidential support and consider various considerations that might help arbitrate between these. The upshot of the discussion is that the so-called 'Law of Likelihood' is to be preferred to any of the alternatives considered.

Philosophers of science take it as a datum that Mayor John's having syphilis explains why he, rather than certain nonsyphilitics, had paresis. Using a new hypothetical example, the case of the two dams, it is argued that three independent considerations invalidate these philosophers' starting point.

In this paper I develop a theory of contrastive why questions that establishes under what conditions it is sensible to ask "why p rather than q?". p and q must be outcomes of a single type of causal process.

In "Knowing the Answer" I argued that knowledge-wh is question-relative. For example, to know when the movie starts is to know the answer p to the question Q of when the movie starts. Berit Brogaard and Jesper Kallestrup have each responded with insightful critiques of my argument, and novel accounts of knowledge-wh. I am grateful to them both for continuing the discussion in so thoughtful a way.

The nature of scientific explanation is controversial. Some maintain that all scientific explanations have to be contrastive in nature (contrastivism). However, others argue that no scientific explanation is genuinely contrastive (non-contrastivism). In addition, a compatibilist view has been recently devloped. It is argued that the debate between contrastivism and non-contrastivism is merely a linguistic dispute rather than a genuine disagreement on the nature of scientific explanation. Scientific explanations are both contrastive and non-contrastive in some sense (compatibilism). This paper examines the (...) debate between contrastivism and non-contrastivism in scientific explanation. It begins with a critical review of the arguments for contrastivism, for non-contrastivism, and for compatibilism and concludes with some remarks on the prospect of the issue. (shrink)

In this paper, I defend epistemological contrastivism—the view that propositional knowledge is a three-place, contrastive relation between an agent, a proposition and a contrast term—against two a priori arguments recently offered by Mikkel Gerken for the conclusion that intuitive judgements exhibiting a contrast effect on knowledge ascriptions are false positives. I show that the epistemic argument for false positives begs the question against contrastivism by assuming the independently implausible claim that knowledge of a contrastive proposition always presupposes knowledge of a (...) related ordinary proposition. This claim is apparently also presupposed by the doxastic argument for false positives, the conclusion of which, I argue, is not only perfectly compatible with epistemological contrastivism but also heavily dependent on a de dicto construal of the relevant knowledge ascriptions. (shrink)

Contrastivism about reasons is the view that ‘reason’ expresses a relation with an argument place for a set of alternatives. This is in opposition to a more traditional theory on which reasons are reasons for things simpliciter. I argue that contrastivism provides a solution to a puzzle involving reason claims that explicitly employ ‘rather than’. Contrastivism solves the puzzle by allowing that some fact might be a reason for an action out of one set of alternatives without being a reason (...) for that action out of a different set of alternatives. (shrink)

: At the turn of the twentieth century, comparative studies of human culture (ethnology) gave way to studies of the details of individual societies (ethnography). While many writers have noticed a political sub-text to this paradigm shift, they have regarded political interests as extrinsic to the change. The central historical issue is why anthropologists stopped asking global, comparative questions and started asking local questions about features of particular societies. The change in questions cannot be explained by empirical factors alone, and (...) following Jarvie, this essay argues that political factors motivate the change. Jarvie's understanding of the role played by egalitarian politics is criticized, and the essay develops a new model of how political or moral values can become constitutive of scientific inquiry. On the erotetic view of explanation, whether one proposition explains another depends on the choice of contrast class and relevance criterion. Since political or moral values can motivate these choices, explanation can depend on non-epistemic values. The essay argues that the comparative questions of nineteenth-century ethnology presupposed that Europeans were superior to other races. It closes by arguing that Fanz Boas recognized the political values implicit in nineteenth-century ethnology and rejected its questions on those grounds. (shrink)

In a brief passage, David Lewis derives from quantum-theory a dilemma regarding the explanation of chance events which he tries to solve by first distinguishing plain from contrastive why-questions have answers. His brevity warrants elaboration and critique. I endorse his derivation, but I make a structural objection to his solution. Once a further distinction is drawn between different kinds of contrastive why-question, his solution can be modified and refined so as to go some way to meeting this objection. However, it (...) cannot resist a deeper objection to the effect that chance events can be given contrastive explanations after all. The alternative solution to the dilemma that I recommend holds Lewis's conception of the 'essence of chance' to be illusory. (shrink)

According to a causal model of explanation, we explain phenomena by giving their causes or, where the phenomena are themselves causal regularities, we explain them by giving a mechanism linking cause and effect. If we explain why smoking causes cancer, we do not give the cause of this causal connection, but we do give the causal mechanism that makes it. The claim that to explain is to give a cause is not only natural and plausible, but it also avoids many (...) of the objections to other accounts of explanation, such as the views that to explain is to give a reason to believe the phenomenon occurred, to somehow make the phenomenon familiar, or to give a Deductive-Nomological argument. Unlike the reason for belief account, a causal model makes a clear distinction between understanding why a phenomenon occurs and merely knowing that it does, and the model does so in a way that makes understanding unmysterious and objective. Understanding is not some sort of super-knowledge, but simply more knowledge: knowledge of the phenomenon and knowledge of its causal history. A causal model makes it clear how something can explain without itself being explained, and so avoids the regress of whys, since we can know a phenomenon's cause without knowing the cause of the cause. It also accounts for legitimate self-evidencing explanations, explanations where the phenomenon is an essential part of the evidence that the explanation is correct, so the explanation can not supply a non-circular reason for believing the phenomenon occurred. There is no barrier to knowing a cause through its effects and also knowing that it is their cause. The speed of recession of a star explains its observed red-shift, even though the shift is an essential part of the evidence for its speed of recession. The model also avoids the most serious objection to the familiarity view, which is that some phenomena are familiar yet not understood, since a phenomenon can be perfectly familiar, such as the blueness of the sky or the fact that the same side of the moon always faces the earth, even if we do not know its cause. Finally, a causal model avoids many of the objections to the Deductive-Nomological model. Ordinary explanations do not have to meet the requirements of the Deductive-Nomological model, because one does not need to give a law to give a cause, and one does not need to know a law to have good reason to believe that a cause is a cause. As for the notorious over-permissiveness of the Deductive-Nomological model, the reason recession explains red-shift but not conversely, is simply that causes explain effects but not conversely, and the reason a conjunction of laws does not explain its conjuncts is that conjunctions do not cause their conjuncts. (shrink)

Two apparently mutually exclusive ideas about the relation between contrastive and non-contrastive explanations can be found in the literature. According to contrastivists, all explanation is contrastive explanation and the supposed existence of non-contrastive explanations can be revealed to be an illusion. According to non-contrastivists, on the other hand, contrastive explanation can be fully analysed in terms of non-contrastive explanation, and is thus not of fundamental importance. In the current article, I discuss the main arguments in favour of and against each (...) of the two positions. This discussion leads to the idea that contrastive explanations are to be understood as parts of a bigger, more complete non-contrastive explanation; but that all actual explanations explain only a limited set of contrasts. I conclude that, once the relation between contrastive and non-contrastive explanations is understood correctly, there remains no substantial issue to divide contrastivism and non-contrastivism. (shrink)

Contrastivism about interrogative understanding is the view that ‘S understands why p’ posits a three-place epistemic relation between a subject S, a fact p, and an alternative to p, q. This thesis stands in stark opposition to the natural idea that a subject S can be said to understand why psimpliciter. I argue that contrastivism offers the best explanation for the fact that evaluations of the form ‘S understands why p’ vary depending on the alternatives to p under consideration. I (...) also show that contrastivism offers valuable resources with which to explain the gradability of interrogative understanding attributions, as well as the sensitivity of these attributions to the perceived degree of epistemic demandingness of different contexts. (shrink)