Author’s Preface (Full Text1)
- This text is devoted to developing an ontology of four-dimensional hunks of matter. I argue that every filled region of spacetime is exactly filled by one such object and that any one of these objects has its actual spatiotemporal configuration and location at every world at which it exists. This ontology should be contrasted with what I take to be our standard ontology, according to which one and the same three-dimensional object exists in its entirety at several times and at several worlds, having a different spatiotemporal shape and location at many of these other worlds. My arguments can be taken to support either of the following conclusions:
For the most part I present my arguments as a defense of (A), but I will also show how to read them as a defense of (B).
- (A) the standard ontology should be rejected and the hunk ontology accepted;
- (B) the standard ontology must really be the hunk ontology rather than the ontology of three-dimensional objects that exist at worlds at which they have different configurations and locations.
- Since I hope to argue for the hunk ontology over the "standard ontology," it is natural that this book should contain both a constructive project and a destructive project, though it is crucial that the two projects not be completely separated. Much of the constructive project is closely connected to the work of David Lewis and much of the destructive project is closely connected to the work of Peter Unger. I hope that I have managed to make original contributions to each of their projects - partly by making some of the same points in new ways, partly by providing new motivations for positions that resemble theirs, and partly by demonstrating the relationships between the two projects.
- The two projects are to a large extent mutually supportive. The rejection of the standard ontology (destructive project) does not seem so extreme once a replacement ontology is provided (constructive project). The replacement ontology, with objects that have temporal parts and restricted transworld existence (constructive), will not seem as problematic once it is noticed that it conflicts with common sense only at the points at which common sense goes wrong anyway (destructive). The two projects also bear upon each other in that each restricts the other. If the replacement ontology is itself going to successfully avoid the attack posed by the destructive project, the relationship between that ontology and our everyday utterances will be more complex than it would first appear. On the other hand, once that relationship is understood, the conclusion of the destructive project can be seen to be less shocking than it would first appear.
- Chapter Summaries:
- In the first2 chapter I begin to explain my recommended ontology of four-dimensional hunks of matter.
- In the second chapter the hunk ontology is developed in more depth, paying special attention to those features of an object that seem to be most tied to its identity - its persistence conditions3 and essential properties.
- In the third4 chapter I present my case against the standard ontology.
- In the fourth and final chapter I show that my rejection of the standard ontology is not as extreme as it might first appear. I offer my hunk ontology as a replacement for the standard ontology.
- Nowhere in this text do I argue for the claim that there are physical objects. Nor do I argue for the claim that if there are physical objects, we can know what these objects are. For the purposes of this work, I take these two claims for granted. If certain skeptical arguments are sound, then we cannot know whether there are physical objects or not. If certain idealist arguments are sound, then there is nothing that is physical (or at least there is nothing that is non-mental). If certain extreme conventionalist arguments are sound, then there are no physical objects, although there may still be matter. If certain Kantian arguments are sound, then there is really nothing that is either physical or mental, although there is still the thing-in-itself. I do not deal with any of these arguments in this text. I am offering an ontology of physical objects on the assumption that there are some. My concern is with the nature of such objects. Even assuming that there are such things, they are not what we think they are. In proposing an ontology I am offering an account of what physical objects would have to be like if there were any.
- One other assumption that I make is that there are such things as sets, states of affairs, possible worlds, and propositions. It is tempting to characterize this assumption generally as a realism about abstract entities. But the distinction between abstract and concrete is not as clear as we might hope, and I do not want to accidentally assume too much by characterizing my assumption in a way that might commit me to some particular theory about the nature of sets, states of affairs, possible worlds, or propositions. My assumption that these objects exist is supposed to have a different status for my project than those assumptions that I adopted in the preceding paragraph. The assumptions that there are physical objects and that we can know what those objects are can be thought of as similar to the assumptions in a conditional proof The assumption presently being considered, on the other hand, is merely a convenience.
- For instance, if someone objects to possible worlds, it is incumbent upon the objector to provide a means of paraphrasing 'possible world' talk into talk that is not explicitly committed to such entities. If it turns out that there are no possible worlds, if the opponent of those entities is successful, then the things that I say in terms of possible worlds should be sayable in other terms. So I do not have to qualify the conclusion of this work by saying that if there are possible worlds, then our standard ontology must be replaced by an ontology of four-dimensional hunks of matter. My arguments would be just as successful if there were no possible worlds, although they would have to be restated if they were to avoid their apparent commitment to such objects. Similar considerations apply to sets, states of affairs, and propositions.
- I emphasize that my discussion is restricted to physical objects. I offer no explicit commentary on mental entities (if they are non-physical). I do assume that people are physical, but this is just for the sake of argument. If they are not physical, then my claims about physical objects do not apply to people. But if they are physical, they are no exception to my claims. I might suggest in passing that even if people were mental, it seems that the Sorites5 paradox would still apply to them. A mentalistic conception of people would be no less vague than a physicalistic6 one. I do not pursue this line of thought in the body of this work. I am content to give an account of what physical things there are.
- This work has, of course, benefited from the advice and criticism of several people….. [snip]
Footnote 2: Part of the first chapter is a revised version of "Heller (Mark) - Temporal Parts of Four-Dimensional Objects", Philosophical Studies Vol. 46 (1984): 323-34.
- Actually, it’s only “substantially” full.
- I’ve removed the acknowledgements.
- I’ve also transplanted the four Chapter Summaries to form Abstracts of the Chapters themselves.
Footnote 4: Much of Chapter 3 is a revised version of "Heller (Mark) - Vagueness and the Standard Ontology"; Nous, Vol. 22 (1988): 109-31.
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