Jonathan Schaffer

Bio: Jonathan Schaffer is an academic researcher from Rutgers University. The author has contributed to research in topics: Metaphysics & Causation. The author has an hindex of 31, co-authored 67 publications receiving 4149 citations. Previous affiliations of Jonathan Schaffer include Australian National University & University of St Andrews.

On What Grounds What

Abstract: ion: The grounding relations are relations of abstraction. The derivative entities, in order to be an ‘‘ontological free lunch’’ and count as no further addition, ought to be already latent within the substances. In other words, the grounding relations should just be ways of separating out aspects that are implicitly present from the start.37 Here is the sort of picture of substances that these diagnostics converge upon: Priority Monism: There is exactly one substance, the whole concrete cosmos. Insofar as there can be no difference in the world without a difference somewhere in the cosmos, priority monism delivers a complete roster of substances.38 This roster is trivially minimal, since the only proper subset of {the cosmos} is Ø, which obviously is not complete. Moreover, this roster is clearly metaphysically general—the ways the cosmos could be just are the ways the world could be.39 And this roster is empirically specifiable since advanced physics is field theoretic physics, and field theory has a natural monistic interpretation in terms of a spacetime bearing properties.40 These diagnostics also converge on: Thick Particularism: Substances are thick particulars (concrete things). 37 Scaltsas imputes a similar view to Aristotle: ‘‘for Aristotle a substance is complex, not because it is a conglomeration of distinct abstract components like matter, form, or properties; a substance is complex because such items can be separated out by abstraction, which is a kind of division of the unified substance’’ (1994: 109) 38 To see the bite of completeness, note that a pluralistic roster comprising point particles in spatiotemporal relations would fail completeness if the whole had emergent features, as are arguably present in entangled quantum systems (Schaffer forthcoming–a: §2.2). 39 In contrast, a pluralistic roster of mereological simples fails generality, since the world could be gunky. That would be a way the world that could be that is not a way that any roster of simples could be (Schaffer forthcoming–a: §2.4). 40 For instance, general relativistic models are triples, where M is a four-dimensional continuously differentiable point manifold, g is a metric-field tensor, and t is a stress-energy tensor (with both g and t defined at every point of M). The obvious ontology here is that of a spacetime manifold bearing fields. Thus Norton notes: ‘‘a spacetime is a manifold of events with certain fields defined on the manifold. The literal reading is that this manifold is an independently existing structure that bears properties’’ (2004). Quantum field theory invites a similar monistic reading. As d’Espagnat explains: ‘‘Within [quantum field theory] particles are admittedly given the status of mere properties, ... But they are properties of something. This something is nothing other than space or space-time, ...’’ (1983: 84) See Schaffer (manuscript) for some further defense of the spacetime-bearing-fields view of what is fundamental. on what grounds what 379 That is, substances have both a that-aspect—the thin particular, the substratum—and a what-aspect—the thickening features, the modes (c.f. Armstrong 1997: 123–6). Plugging in priority monism, the that-aspect of the cosmos is spacetime, and the what-aspect of it is its fields. So among the derivative categories are those of substratum and mode: Substratum and Mode as Derivative: substratum and mode are abstractions from thick particulars. Another derivative category will be the partialia, abstracted via: Universal Decomposition: The cosmos may be arbitrarily decomposed into parts. From priority monism plus universal decomposition, the entirety of the actual concrete mereological hierarchy of thick particulars is generated (whether or not the world is gunky). Wholes are complete and concrete unities, and partialia their incomplete aspects, arising from a process of ‘‘one-sided abstraction’’ (Bradley 1978: 124). With the partialia thus grounded, it remains to ground abstracta (such as numbers and possibilia) in the actual concrete realm. Here matters are too complicated to discuss further within the scope of this paper. But perhaps I have said enough to illustrate how at least one of the many possible neo-Aristotelian programs might look. To conclude: metaphysics as I understand it is about what grounds what. It is about the structure of the world. It is about what is fundamental, and what derives from it.41

Monism: The Priority of the Whole

Abstract: Consider a circle and a pair of its semicircles. Which is prior, the whole or its parts? Are the semicircles dependent abstractions from their whole, or is the circle a derivative construction from its parts? Now in place of the circle consider the entire cosmos (the ultimate concrete whole), and in place of the pair of semicircles consider themyriad particles (the ultimate concrete parts).Which if either is ultimately prior, the one ultimate whole or its many ultimate parts? The monist holds that the whole is prior to its parts, and thus views the cosmos as fundamental, with metaphysical explanation dangling downward from the One. The pluralist holds that the parts are prior to their whole, and thus tends to consider particles fundamental, with

Grounding in the image of causation

Abstract: Grounding is often glossed as metaphysical causation, yet no current theory of grounding looks remotely like a plausible treatment of causation. I propose to take the analogy between grounding and causation seriously, by providing an account of grounding in the image of causation, on the template of structural equation models for causation.

Is There a Fundamental Level

Abstract: 1. Talk about ‘‘the fundamental level of reality’’ pervades contemporary metaphysics. The fundamentalist starts with (a) a hierarchical picture of nature as stratified into levels, adds (b) an assumption that there is a bottom level which is fundamental, and winds up, often enough, with (c) an ontological attitude according to which the entities of the fundamental level are primarily real, while any remaining contingent entities are at best derivative, if real at all. Thus the physicalist claims thatmicrophysical theory (or some future extension thereof) describes the fundamental level of reality on which all else supervenes; theHumean claims that all supervenes on the distribution of local, fundamental qualities in spacetime; the epiphenomenalist claims that all causal powers inhere at the fundamental level; and the atomist claims that there are no macroentities at all but only fundamental entities in various arrangements. I find the hierarchical picture of nature in (a) plausible as reflected in the structure and discoveries of the sciences, and consider the ontological primacy of the fundamental entities in (c) a natural (though not inevitable) conclusion. In any case I will not discuss these issues here. Rather I will discuss the assumption (b) that there exists a fundamental level; first because it is almost entirely neglected; second because, as I will argue, there is no evidence in its favor; and third because the hierarchical picture minus (b) yields a far more palatable metaphysic in which, contra (c), all entities are equally real. NOUS 37:3 (2003) 498–517

Causation by Disconnection

Abstract: The physical and/or intrinsic connection approach to causation has become prominent in the recent literature, with Salmon, Dowe, Menzies, and Armstrong among its leading proponents. I show that there is a type of causation, causation by disconnection, with no physical or intrinsic connection between cause and effect. Only Hume-style conditions approaches and hybrid conditions-connections approaches appear to be able to handle causation by disconnection. Some Hume-style, extrinsic, absence-relating, necessary and/or sufficient condition component of the causal relation proves to be needed.

"relative State" Formulation of Quantum Mechanics

Abstract: The task of quantizing general relativity raises serious questions about the meaning of the present formulation and interpretation of quantum mechanics when applied to so fundamental a structure as the space-time geometry itself. This paper seeks to clarify the foundations of quantum mechanics. It presents a reformulation of quantum theory in a form believed suitable for application to general relativity. The aim is not to deny or contradict the conventional formulation of quantum theory, which has demonstrated its usefulness in an overwhelming variety of problems, but rather to supply a new, more general and complete formulation, from which the conventional interpretation can be deduced. The relationship of this new formulation to the older formulation is therefore that of a metatheory to a theory, that is, it is an underlying theory in which the nature and consistency, as well as the realm of applicability, of the older theory can be investigated and clarified.