According to Peter van Inwagen, visible inanimate objects do not, strictly speaking, exist. In defending this controversial thesis, he offers fresh insights on such topics as personal identity, commonsense belief, existence over time, the phenomenon of vagueness, and the relation between metaphysics and ordinary language.

The topic of this book is material objects. Like most interesting concepts, the concept of a material object is one without precise boundaries.

In my book Four-dimensionalism (chapter 4, section 9), I argued that fourdimensionalism – the doctrine of temporal parts – follows from several other premises, chief among which is the premise that existence is never vague. Kathrin Koslicki (preceding article) claims that the argument fails since its crucial premise is unsupported, and is dialectically inappropriate to assume in the context of arguing for four-dimensionalism. Since the relationship between four-dimensionalism and the non-vagueness of existence is not perfectly transparent, I think the argument (...) would retain some interest even if the premise were wholly unsupported; it would show that anyone who accepts that premise (which seems reasonable enough to me though perhaps not to others) must accept four-dimensionalism. Still, Koslicki is right that my defense of the premise was thin. So I will now try to do better. The new defense will have further premises, which could ultimately be rejected by opponents of four-dimensionalism, and so the argument retains the form: anyone who thinks certain things (which seem reasonable enough to me though perhaps not to others) must believe four-dimensionalism. But that’s metaphysics for you. I should also say that, in addition to the material on vague existence, there is more in Koslicki’s excellent paper which I cannot discuss here. I agree with much of it;1 and where we disagree there are formidable challenges, some of which I hope to address in the future. (shrink)

‘Restricted composition’ says that there are some composite objects. And it says that some objects jointly compose nothing at all. The main threat to restricted composition is the influential and widely defended Vagueness Argument. We shall see that the Vagueness Argument fails. In seeing how this argument fails, we shall discover a new focus for the debate over composition's extent.

To generate explanatory theory, ecologists must wrestle with how to represent the extremely many, diverse causes behind phenomena in their domain. Early twentieth-century plant ecologists Frederic E. Clements and Henry A. Gleason provide a textbook example of different approaches to explaining vegetation, with Clements allegedly committed, despite abundant exceptions, to a law of vegetation, and Gleason denying the law in favor of less organized phenomena. However, examining Clements's approach to explanation reveals him not to be expressing a law, and instead (...) to be developing an explanatory structure without laws, capable of progressively integrating causal complexity. Moreover, Clements and Gleason largely agree on the causes of vegetation; but, since causal understanding here underdetermines representation, they differ on how to integrate recognized causes into general theory---that is, in their methodologies. Observers of the case may have mistakenly assumed that scientific representation across the disciplines typically aims at laws like Newton's, and that representations always reveal scientists' metaphysical commitments. Ironically, in the present case, this assumption seems to have been made even by observers who regard Clements as naı¨ve for his alleged commitment to an ecological law. (shrink)

Four- Dimensionalism defends the thesis that the material world is composed of temporal as well as spatial parts. This defense includes a novel account of persistence over time, new arguments in favour of the four-dimensional ontology, and responses to the challenges four- dimensionalism faces." "Theodore Sider pays particular attention to the philosophy of time, including a strong series of arguments against presentism, the thesis that only the present is real. Arguments offered in favour of four- dimensionalism include novel arguments based (...) on time travel, the debate between spacetime substantivalists and relationalists, and vagueness. Also included is a comprehensive discussion of the paradoxes of coinciding material objects, and a novel resolution of those paradoxes based on temporal counterpart theory. In conclusion Sider replies to prominent objections to four- dimensionalism, including discussion of the problem of the rotating homogenous disk. (shrink)

For more than a century, nature lovers have held fast to the belief that preserving the wild means keeping people out. Today, policies that dictate everything from the regulation of ocean fisheries to the protection of endangered species are founded on an almost religious conviction that nature is constant, eternal, self-regulating - "in balance" - save only when man intrudes. But as Stephen Budiansky dramatically illustrates, these credos of modern environmentalism are flatly contradicted by modern ecological research and have led (...) to spectacular disasters. Because paradoxes abound in nature, many of the straightforward solutions that have been proposed to save endangered species, eliminate pests, or enlarge populations of game animals have backfired again and again. Based on a mythical view of a natural world where man never treads, such policies threaten to destroy the very things they claim to preserve - biodiversity, endangered species, unique wilderness landscapes. Now, however, modern ecological research is providing the tools for effective environment management by revealing for the first time how ecosystems really work and interact. This new science of nature management, rooted in the mathematical relationships that link the fates of all plants and animals, is being applied to actual problems, such as elk overpopulation in Yellowstone, management of game bird populations and fisheries, and ecological restoration. (shrink)

In _Real Natures and Familiar Objects_ Crawford Elder defends, with qualifications, the ontology of common sense. He argues that we exist -- that no gloss is necessary for the statement "human beings exist" to show that it is true of the world as it really is -- and that we are surrounded by many of the medium-sized objects in which common sense believes. He argues further that these familiar medium-sized objects not only exist, but have essential properties, which we are (...) often able to determine by observation. The starting point of his argument is that ontology should operate under empirical load -- that is, it should give special weight to the objects and properties that we treat as real in our best predictions and explanations of what happens in the world. Elder calls this presumption "mildly controversial" because it entails that arguments are needed for certain widely assumed positions such as "mereological universalism". Elder begins by defending realism about essentialness. He then defends this view of familiar objects against causal exclusion arguments and worries about vagueness. Finally, he argues that many of the objects in which common sense believes really exist, including artifacts and biological devices shaped by natural selection, and that we too exist, as products of natural selection. (shrink)