Metaphysics: Contemporary Themes Peter Simons Note: This text appeared in The Philosophers’ Magazine, Issue 39 (2007), 64–8, an issue called Philosophy: The State of Our Art; but with the section headings taken out. I liked the headings, so here is the structured version. Confounding earlier predictions of naysayers and sceptics, by the beginning of the twenty-first century, metaphysics had re-emerged for the first time in decades as a vital, progressive and exciting branch of philosophy. Although the most strident criticisms came from early analytic philosophers such as Carnap, it is analytical metaphysics that has led the way. But rather than trace the stages of the revival of metaphysics, we consider a spread of contemporary themes which have been especially fruitful in expanding the circle of metaphysical discussion from its modest beginnings at the hands of Strawson and Quine in mid-century. The topics are divided into four groups: Expanding the Toolbox; Ontological Speculations; Systematics; and Applications. Expanding the Toolbox Metaphysics emerged from its 20th century purdah with the assistance of logic and language. The realisation that an adequate account of the meaning and truth of statements required mention of divers objects referred to, predicated or sustaining truth, undercut positivist criticisms. Semantics became the rescue line for metaphysics. But semantics in analytic philosophy, like much else, was under the sway of this philosophy’s early preoccupation with mathematics and its foundations. As a result, the objects wheeled out to do semantic duty as meanings and referents for terms, predicates, sentences and theories tended to be crumbs from the mathematician’s table: sets, functions, and constructs therefrom. To avoid restrictive and unrealistic accounts of the world’s plethora, it became necessary to rediscover concepts that would provide a broader basis on which to build metaphysical
theories. Here are four such conceptual areas: modality, mereology, dependence, and emergence. Modality Mathematical language is extensional, but elsewhere modal concepts abound. Accommodating modality, first in logic, then via its semantics through ontology, led to an explosion of theories and controversies. Of the competing semantic accounts of modality, the most prominent has been the semantics of possible worlds, initiated by Kripke and others, but carried to its ontological extreme by David Lewis, for whom all possible worlds exist and are as real as our actual world. Despite its widespread rejection, Lewis’s realism of possible worlds has done more than any other doctrine to stimulate recent metaphysical discussion. Even sceptics and modal anti-realists can be heard talking the talk of worlds, transworld identity and counterparts. The complex arguments pro and contra possible worlds, what might stand in their place, how one might provide an ontologically lightweight alternative, not only constitute metaphysics, they stimulate further metaphysics, and provide a framework for further discussion of many topics. Mereology Standard predicate logic and set theory offer little for the metaphysician beyond predication, identity and set membership with which to account for the nature and constitution of objects. These miss out the part-whole relation, endemic to everyday and scientific thought. Rescuing mereology from the mathematicians has enlarged the palette of ontological concepts and offers rich opportunities for ontological construction and controversy. One such is whether all collections of individuals compose a unique sum-individual, having them and nothing outside them as its parts. The answers range from universalism, that every collection has a sum, to nihilism, that none do, only atomic individuals exist. In between are various strengths of common sense, that some collections compose and others don’t. Another issue is whether you, me and the cat next door have temporal parts (see Persistence). Yet another is whether the part-relation is vague (see Vagueness), whether extended
objects have extended parts (see Composition), and how the parts of artefacts are best classified (see Engineering). Dependence Lewis Carroll’s Cheshire Cat aside, smiles don’t wander the world alone, but only in faces. Zen Buddhism aside, it takes two colliding things to make a clapping noise. Any object which requires others to exist for it to exist (or take place) is ontologically dependent on those. Independence distinguishes substances from accidents (see Tropism), and sets may be said to depend on their elements. Dependence is arguably a more intimate relation than necessary co-occurrence, since an object and its singleton set necessarily co-occur, but the singleton depends on the element, not vice versa. Emergence Unfashionable since the 1920s, this difficult concept is making a comeback as reductive accounts of mind (see Mind) and other complexities fail to satisfy more philosophers. Ontic emergence is the presence of a kind of thing inconstructible from a given basis by stated modes of complexification. Epistemic emergence is a kind of unexpectedness, which real or idealized epistemic subjects cannot predict from knowledge of said basis. Epistemic emergence may be compatible with lack of its ontic counterpart, if ontology and even ideal knowledge can come apart. Watch this space. There are other putative formal concepts that need to be added to these to build up the general explanatory and descriptive power of ontology. Several of those will emerge in passing below.
Ontological Controversies What is there (really)? Ask any two metaphysicians and you are likely to get at least two opinions. Here are some of the controversies that have divided recent metaphyicians. Persistence: 3D or 4D Objects? Cats differ from journeys in that the latter but not the former have temporal parts. Journeys have four dimensions, cats only three. A cat is a continuant (C), a journey an occurrent (O). Thus saith common sense. But many philosophers believe that to explain change we need to assign Kitty temporal parts too. Once a minority, the fourdimensionalists are now a strong lobby. Every possible combination of view exists: only Cs, only Os, both equally, both but Cs prior, both but Os prior. Cats and journeys go on as before, whatever that amounts to. Time: A, B, or P? Still on time: following McTaggart’s famous 1908 argument against the reality of time, philosophers have become used to distinguishing A-concepts such as past, present, and future, from B-concepts such as earlier, later, and simultaneous with. Hugh Mellor claims that McTaggart’s argument when adapted shows that A-features are not objectively real whereas B-features survive unscathed. A passage or flow of time does not exist, but time itself qua the wherein of happenings is acceptable. But we have the impression that time passes, so that needs explaining. A more radically restrictive position is that of presentists, a group headed originally by logician Arthur Prior, who claim that only the present and present things are real or exist, and past and future things, events and times are not real. Consonant though this is with the superficialities of linguistic tense, it still has to huff and puff to make sense of true claims about the past and the future, such as that there were once dinosaurs.
Mind: Physical, or Not? Post-war metaphysics really got into its stride with a good old-fashioned metaphysical problem: mind and body. Deflationary attempts to dissolve the problem by Wittgenstein and Ryle having failed, Herbert Feigl proclaimed it not a pseudo-problem, and the “Australian” materialists Ullin Place, Jack Smart and David Armstrong countered with a good old-fashioned metaphysical proposal: mental events and processes are simply identical with certain brain events and processes. Following the demise of behaviourism, subjective phenomena becoming again respectable, the boot swung to the other foot: can the phenomenal side of consciousness be explained physicalistically? Contentions that it cannot, based on inability to see how physical processes can intelligibly give rise to consciousness (David Chalmers’s “hard problem”: see also Emergence), led on the one hand to attepts to do away with phenomena altogether (eliminativism) and on the other to a resurgence of various forms of Cartesian dualism. While neuroscientists beaver away to try and uncover the facts, philosophers walk in where cautious scientists fear to tread, and declare the problem solved, solvable, or unsolvable. Probably not a good idea to hold one’s breath on this one. Composites: All, Some, or None? Mereology (q.v.) gives rise to the following metaphysical questions: does any collection of individuals whatsoever have a mereological sum? Compositional nihilism says no collections do: only atoms exist. Universalism says all collections do: 4Dists David Lewis and Ted Sider claim this can only be denied by thinking the concept of a single object is a vague one (if so, so be it: see Vagueness). The sensible moderate truth lies somewhere in between, but where exactly is not obvious. Peter Van Inwagen for instance says that apart from atoms only organisms exist, which is intermediate but immoderate.
Truthmakers: All, Some, or None? An object makes a truth true when said truth is true because said object exists. The object is then a truthmaker for that truth. A certain famous collision between the Titanic and an anonymous iceberg made true that the Titanic collided with an iceberg. Truthmaking as a relation between truthmakers and truth-bearers is a prime place where the rubber of language hits the road of reality. Truthmaking, unlike correspondence, is not suspiciously one-one. But what kinds of things are truthmakers? And do all truths have truthmakers or only some? Truthmakers are often taken to be special kinds of entity: facts or states of affairs (Russell, Wittgenstein, Armstrong). But not all truthmaker theorists think so. Some suborn ordinary objects or tropes (see Tropism) to make true. Truthmaker maximalism is the view that all truths have truthmakers. It has problems with true generalizations and true negative existentials. So some truthmaker theorists back off and settle for the weaker idea that truth supervenes on being (Bigelow; Mulligan, Simons and Smith). They accept certain truths as lacking truthmakers. From there it is but a step – albeit one which rejects the whole show – to denying that truthmakers are needed at all. Vagueness: Out There? It is usually contended that vagueness is either a matter of semantic inexactitude or defective knowledge. But can things themselves be vague? If a case of vagueness appears otherwise inexplicable, maybe so. Then perhaps (pace Gareth Evans) there can be vague identity sentences; only slightly less problematically, mereology (q.v.) may be vague. Systematics Systematic metaphysics has a dubious name even among metaphysicians, but all the great metaphysicians strove for a connected theory of everything, and patchwork metaphysics hardly merits the name. Among contemporary grand speculative theories of everything we may mention
Tropism First proposed by D. C. Williams, seconded by Keith Campbell and John Bacon, tropism claims the world is a congeries of tropes, grouped by compresence (things) and similarity (kinds). Nominalistic in tendency and minimally slim in categories, it has attracted a discerning few. Factualism Here, the world is one of facts or states of affairs (and their abstractive components, things and universals). Sketched by Young Wittgenstein, semanticized by Barwise and Perry, systematized by David Armstrong, factualism automatically provides facts as truthmakers (q.v.). Humeanism David Lewis’s universe is a disconnected plenitude of spatiotemporally maximal worlds, each one composed of things with properties in relations, every individual bound to one world, and no individual linked by necessity (such as dependence) to any other individual. Such dispersed ontological loners are modern Humean atoms, but unlike Hume, Lewis locates modality out there, not in here. Aristotelianism A world of individuals and universals, substances and accidents, as if out of Aristotle’s Categories, can be found in several modern metaphysical systems, most prominently those of Michael Loux, Jonathan Lowe, and with a logically refined Scotist account of essences, Kit Fine. Vivat Philosophus! Applications: Coming Soon, to a Discipline Near You Metaphysics has always lurked around the edge of non-philosophical disciplines, nudging scientists into self-awareness about their objects of study: mathematics,
physics, biology and social science have all inspired hefty ontological controversies which even intrude into the disciplines themselves. Other philosophically proximate studies, such as psychology, ethics and aesthetics, are constantly questioning the status of their objects. But metaphysics is beginning to turn up in the most unlikely places, such as ... Engineering Practical philosophy writ large and carried out with real materials is engineering. The complexities and uncertainties of large-scale engineering projects—buildings to bridges, cars to computers, ships to spacecraft—require sophisticated planning techniques that would have thrilled Aristotle, and the large-scale computer models devised to design, run and monitor such projects often fall pathetically short of ontological sophistication. Enter the worldly ontologist, armed with a theory of action, intention, artefacts and mereology. Will she be useful and accepted? It’s too early to say. Medicine Another Aristotelian field: the living body, its bits, its functions and its malfunctions. One would think millennia of study would have rendered medicine ontologically transparent. Unfortunately, contemporary medical databases suggest otherwise: an ontological palette consisting of only is_a and part_of, as do many such databases, is unlikely to rise to the sophistication of a practitioner. Doctors being too busy healing to design such systems, perhaps ontology-appliers can do better. Geography Now that computers and satellites make many of our maps, the relation of physical geography to numbers and ontological features needs attention. Moreover, the spatial layout of town, country and wilderness is not just physical, but takes a detour through human thinking. Whether reflection on such a detour can avoid unscientific
postmodern nonsense is a moot point, but perhaps again the worldly metaphysician needs to come to the rescue.
Literature: Where to Look There are many excellent introductions to modern metaphysics, such as Loux, Michael. Metaphysics: A Contemporary Introduction. London: Routledge, 2001. Lowe, E. Jonathan. A Survey of Metaphysics. Oxford: Oxford University Press, 2002. Numerous collections of essays and readings cover the gamut of the subject. For easily accessible, informative articles, browse the Stanford Encyclopedia of Philosophy: http://plato.stanford.edu/ For controversy and excitement from the bleeding edge, browse the latest issues of the best philosophy journals. Do not expect final answers.
