Jonathan Schaffer

Quantum mechanics seems to portray nature as nonseparable, in the sense that it allows spatiotemporally separated entities to have states that cannot be fully specified without reference to each other. This is often said to implicate some form of “holism.” We aim to clarify what this means, and why this seems plausible. Our core idea is that the best explanation for nonseparability is a “common ground” explanation, which casts nonseparable entities in a holistic light, as scattered reflections of a more unified underlying reality.

Knowledge ascriptions seem context sensitive. Yet it is widely thought that epistemic contextualism does not have a plausible semantic implementation. We aim to overcome this concern by articulating and defending an explicit contextualist semantics for ‘know,’ which integrates a fairly orthodox contextualist conception of knowledge as the elimination of the relevant alternatives, with a fairly orthodox “Amherst” semantics for A-quantification over a contextually variable domain of situations. Whatever problems epistemic contextualism might face, lack of an orthodox semantic implementation is not among them.

In _A Companion to David Lewis_, Barry Loewer and Jonathan Schaffer bring together top philosophers to explain, discuss, and critically extend Lewis's seminal work in original ways. Students and scholars will discover the underlying themes and complex interconnections woven through the diverse range of his work in metaphysics, philosophy of language, logic, epistemology, philosophy of science, philosophy of mind, ethics, and aesthetics. The first and only comprehensive study of the work of David Lewis, one of the most systematic and influential philosophers of the latter half of the 20th century Contributions shed light on the underlying themes and complex interconnections woven through Lewis's work across his enormous range of influence, including metaphysics, language, logic, epistemology, science, mind, ethics, and aesthetics Outstanding Lewis scholars and leading philosophers working in the fields Lewis influenced explain, discuss, and critically extend Lewis's work in original ways An essential resource for students and researchers across analytic philosophy that covers the major themes of Lewis's work

According to a line of thought tracing from Descartes, Leibniz, and Locke through to Kripke, Levine, and Chalmers, there is a special explanatory gap arising between the physical and the phenomenal. I argue that the physical-phenomenal gap is not special but rather that such gaps are pervasive, lurking in the transition from the physical to the chemical and in every concrete transition from more to less fundamental. Correlatively, I argue that such gaps are unproblematic, so long as they are bridged by substantive principles of metaphysical grounding. So I articulate a form of physicalism — “ground physicalism” — on which the physical grounds the chemical, the biological, and the psychological, and explain how ground physicalism resolves explanatory gap worries.

You drop the glass. It shatters. Here there are two distinct events, related by causation. What is this relation? ;I argue that the causal relation is best understood as the relation of being a probability-raiser of a process. I take the causal relata to be property instances at spatiotemporal regions, analyze the notion of a process in terms of sequences of events related by nomic subsumption , and understand probability-raising as counterfactual chance dependence in the style of David Lewis. Thus causes are understood as property instances on which the sequence of property instances constituting the lawful production of the effect depends. ;The understanding of causation offered here synthesizes the leading extant analyses of causation, which divide into probability-raising and process-linkage . I argue that the synthesis offered improves on its predecessors by developing a series of four problem cases: preemption, which shows causation without probability-raising, overlapping, which shows probability-raising without causation, double prevention, which shows causation without process-linkage, and mere traces, which shows process-linkage without causation. These objections interlock: the preempting cause and trace noncause are both process-linked to, but not probability-raising of, their alleged effects, while the double preventing cause and overlapping noncause are both probability-raising of, but not process-linked to, their alleged effects. Understanding causes as probability-raisers of processes resolves this problematic. A continuity requirement is then added which preserves these solutions, renders the relation continuous and transitive, and resolves a further problem case combining preemption and double-prevention involving causation without probability-raising or process-linkage

Are the sparse properties drawn from all the levels of nature, or only the fundamental level? I discuss the notion of sparse property found in Armstrong and Lewis, show that there are tensions in the roles they have assigned the sparse properties, and argue that the sparse properties should be drawn from all the levels of nature. The issue has direct bearing on reductionism. If the sparse properties are drawn from all the levels of nature, then macro‐scientific properties are just as primary as micro‐scientific properties, and do not need to be reduced to them.

What conception of causation is at work in the law? I argue that the law implicitly relies on a contrastive conception. In a liability case where the defendant's breach of duty must be shown to have caused the plaintiff's damages, it is not enough to consider what would have happened if the cause had not occurredthe law requires us to look to a specific replacement for the effect, which in this case is the hypothetical outcome in which the plaintiff came off better. In place of I suggest the more explicit An explicitly contrastive approach can thus potentially help the lawyer phrase her causal question in a more explicit way, while shedding light on our conception of causation

The skeptic says that “knowledge” is an absolute term, whereas the contextualist says that “knowledge” is a relationally absolute term. Which is the better hypothesis about “knowledge”? And what implications do these hypotheses about “knowledge” have for knowledge? I argue that the skeptic has the better hypothesis about “knowledge”, but that both hypotheses about “knowledge” have deeply anti-skeptical implications for knowledge, since both presuppose our capacity for epistemically salient discrimination.

How should one understand knowledge-wh ascriptions? That is, how should one understand claims such as ‘‘I know where the car is parked,’’ which feature an interrogative complement? The received view is that knowledge-wh reduces to knowledge that p, where p happens to be the answer to the question Q denoted by the wh-clause. I will argue that knowledge-wh includes the question—to know-wh is to know that p, as the answer to Q. I will then argue that knowledge-that includes a contextually implicit question. I will conclude that knowledge is a question-relative state. Knowing is knowing the answer, and whether one knows the answer depends (in part) on the question

Does G. E. Moore know that he has hands? Yes, says the dogmatist: Moore’s hands are right before his eyes. No, says the skeptic: for all Moore knows he could be a brain-in-a-vat. Yes and no, says the contrastivist: yes, Moore knows that he has hands rather than stumps; but no, Moore does not know that he has hands rather than vat-images of hands. The dogmatist and the skeptic suppose that knowledge is a binary, categorical relation: s knows that p. The contrastivist says that knowledge is a ternary, contrastive relation: s knows that p rather than q.

On the truthmaker view of ontological commitment [Heil (From an ontological point of view, 2003); Armstrong (Truth and truthmakers, 2004); Cameron (Philosophical Studies, 2008)], a theory is committed to the entities needed in the world for the theory to be made true. I argue that this view puts truthmaking to the wrong task. None of the leading accounts of truthmaking—via necessitation, supervenience, or grounding—can provide a viable measure of ontological commitment. But the grounding account does provide a needed constraint on what is fundamental. So I conclude that truthmaker commitments are not a rival to quantifier commitments, but a needed complement. The quantifier commitments are what a theory says exists, while the truthmaker commitments are what a theory says is fundamental.

Quantum mechanics seems to portray nature as nonseparable, in the sense that it allows spatiotemporally separated entities to have states that cannot be fully specified without reference to each other. This is often said to implicate some form of “holism.” We aim to clarify what this means, and why this seems plausible. Our core idea is that the best explanation for nonseparability is a “common ground” explanation, which casts nonseparable entities in a holistic light, as scattered reflections of a more unified underlying reality.