Yuri Balashov

Are shapes of objects intrinsic to them? The issue has been intensely debated. Special relativity (SR) adds a new dimension to it by relativizing three-dimensional (3D) shapes not just to times, but to times-in-frames. Arguably, however, such relativized spatial shapes are mere perspectival representations of an invariant, hence intrinsic, four-dimensional (4D) shape of an object in Minkowski spacetime. In a recent note, Matthew Davidson questions the intrinsicality of 4D shapes in SR. I show that his conclusion and the reasoning behind it are in error

Are the laws of nature real? Do they belong to the world or merely reflect the way we speak about it? And if they are real, what sort of entity are they? These questions have been intensely debated by philosophers. Modern cosmology, however, has given such questions a new twist by introducing a unique perspective on physical reality, the perspective which I shall call the cosmological point of view. In this perspective, the universe as a whole presents itself as a single individual entity that undergoes a radical change with time. Laws of physics, on the other hand, have both local and global significance. They characterize how things behave locally. But they also characterize the entire universe. This suggests an interesting connection between the universe as a whole and what laws of physics hold in this universe. From the cosmological point of view, these two totalities, the laws of physics and the universe, may be related. But how exactly? Are the laws “inscribed” in the fabric of the universe or do they in some sense “precede” it in the order of being? If the latter, what is a “medium,” over and above the physical universe, in which physical laws are “written”? If the former, are they but a consequence of the universe’s very existence? And if so, how could the laws of physics survive the dramatic change the physical state of the universe underwent in the course of time?

I offer a new criticism of the argument from vagueness to four-dimensionalism [Sider 2001. The argument is modelled after an older argument for mereological universalism [Lewis 1986 and may be looked upon as a tightened-up and extended version of the latter. While I agree with other critics [Koslicki 2003; Markosian 2004 that the argument from vagueness fails precisely because of this affinity, my recipe for dealing with it is different. I reject the assumption, shared by Sider with his opponents, that synchronic composition and ‘minimal diachronic fusion’ are sufficiently similar to use considerations inspired by the analysis of the former to bear on the latter. My objection to a crucial premise of the argument from vagueness turns on the relevant aspect of dissimilarity between these two cases.

I had excruciating back pain last night. The next day I went to a spa and the pain disappeared. Psychologically speaking, my pain is gone. Where is it, speaking ontologically? Atheorists have an easy time here (more or less). But B-theorists who think that persons persist by enduring are in trouble. Why am I finding myself at this particular time, with this particular set of experiences, rather than at numerous other times, with different experiences, despite the fact that all times are on the same ontological footing and I am wholly present at all of them? I argue that the Puzzle of the Experience of the Present is a real challenge for B-theorists, and the best way to deal with it is to adopt the stage view of persistence.

Four-dimensionalism, or perdurantism, the view that temporally extended objects persist through time by having (spatio-)temporal parts or stages, includes two varieties, the worm theory and the stage theory. According to the worm theory, perduring objects are four-dimensional wholes occupying determinate regions of spacetime and having temporal parts, or stages, each of them confined to a particular time. The stage theorist, however, claims, not that perduring objects have stages, but that the fundamental entities of the perdurantist ontology are stages. I argue that considerations of special relativity favor the worm theory over the stage theory.

Duhem's and Quine's holistic theses, when properly understood, allow methodologically responsible ways of resolving a conflict between a theoretical system and experience; they only deny the possibility of doing it in an epistemically persuasive way. By developing a "string" model of scientific tests I argue that the pattern of interaction between the elements of a theoretical system arising in response to multiple adverse data can be helpful in locating a "weak spot" in it. Combining this model with anti-holistic arguments of Popper, Greenwood, and Lakatos significantly reinforces their joint power

I examine the issue of persistence over time in thecontext of the special theory of relativity (SR). Thefour-dimensional ontology of perduring objects isclearly favored by SR. But it is a different questionif and to what extent this ontology is required, andthe rival endurantist ontology ruled out, by thistheory. In addressing this question, I take theessential idea of endurantism, that objects are whollypresent at single moments of time, and argue that itcommits one to unacceptable conclusions regardingcoexistence, in the context of SR. I then propose anddiscuss a plausible account of coexistence forperduring objects, which is free of these defects. This leaves the endurantist room for some maneuvers. I consider them and show that they do not really helpthe endurantist out. She can accommodate the notionof coexistence in the relativistic framework only atthe cost of renouncing central endurantist intuitions.

Most four-dimensionalists, including both worm and stage theorists, endorse mereological universalism, the thesis that any class of objects has a fusion. But the marriage of fourdimensionalism and universalism is unfortunate and unprofitable: it creates a recalcitrant problem for stage theory’s account of lingering properties, such as writing ‘War and Piece’ and traveling across the tennis court, which take time to be instantiated. This makes it necessary to impose a natural restriction on diachronic composition.