Online research in philosophy

Ever since the now infamous comments made by Hermann Minkowski in 1908 concerning the proper way to view space-time, the debate has raged as to whether or not the universe should be viewed as a four-dimensional, unified whole wherein the past, present, and future are equally real or whether the views espoused by the possibilists, historicists, and presentists regarding the unreality of the future (and, for presentists, the past) are best. Now, a century after Minkowski’s proposed blockworld first sparked debate, we seek a more conclusive argument in favor of the eternalist picture of space-time. Utilizing an argument based on the relativity of simultaneity in the tradition of Putnam and Rietdijk and novel but reasonable assumptions as to the nature of “reality”, we will show that the past, present, and future are equally real, thus ruling out presentism and other theories of time that bestow special ontological status to the past, present, or future as untenable. Finally, we will respond to our critics who would suggest that: 1) there is no metaphysical difference between the positions of eternalism and presentism, 2) the present must be defined as the “here” as well as the “now”, or 3) presentism is correct and our understanding of relativity is incomplete because it does not incorporate a preferred frame. We call eternalist response 1 deflationary since it purports to dissolve or deconstruct the age-old debate between the two views and response 2 compatibilist because it does nothing to alter special relativity (SR) arguing instead that SR unadorned has the resources to save presentism. Response 3 we will call incompatibilism because it adorns SR in some way in order to save presentism a la some sort of preferred frame. We will show that neither move 1 nor 2 can save presentism and move 3 is not well motivated at this juncture except as an ad hoc device to refute eternalism.

Although considerations based on contemporary space-time theories, such as special and general relativity, seem highly relevant to the debate about persistence, their significance has not been duly appreciated. My goal in the paper is twofold: (1) to reformulate the rival positions in the debate (i.e., endurantism (three-dimensionalism) and perdurantism (four-dimensionalism, the doctrine of temporal parts)) in the framework of special relativistic space-time; and (2) to argue that, when so reformulated, perdurantism exhibits explanatory advantages over endurantism. The argument builds on the fact that four-dimensional entities extended in space as well as time are relativistically invariant in a way three-dimensional entities are not.

This paper argues that the Einstein-Minkowski space-time of special relativity provides an adequate model for classical tense logic, including rigorous definitions of tensed becoming and of the logical priority of proper time. In addition, the extension of classical tense logic with an operator for predicate-term negation provides us with a framework for interpreting and defending the significance of future contingency in special relativity. The framework for future contingents developed here involves the dual falsehood of non-logical contraries, only one of which becomes true. This has several methodological, metaphysical and physical advantages over the alternative traditional frameworks for handling future contingents.

What is the difference between time and space? This question, once a central one in metaphysics, has not been treated kindly by recent history. By joining together space and time into spacetime Minkowski sapped some of the spirit out of this project. That is unfortunate, however, for even in relativistic theories there remain sharp and important metrical and topological distinctions between the timelike and spacelike directions of spacetime. Questions about what these differences are, why they exist and how they are related are fascinating. Why, for instance, is time one-dimensional in virtually all physical theories? What does the “minus sign” in the relativistic metric have to do with time? Is there a connection between the two? At a time when researchers in quantum gravity regularly propose speculative theories with no time at all, a better understanding of time in physics is all the more important—even if only to see what is lost by its absence.

Here are two ways space might be (not the only two): (1) Space is “pointy”. Every finite region has infinitely many infinitesimal, indivisible parts, called points. Points are zero-dimensional atoms of space. In addition to points, there are other kinds of “thin” boundary regions, like surfaces of spheres. Some regions include their boundaries—the closed regions—others exclude them—the open regions—and others include some bits of boundary and exclude others. Moreover, space includes unextended regions whose size is zero. (2) Space is “gunky”.1 Every region contains still smaller regions—there are no spatial atoms. Every region is “thick”—there are no boundary regions. Every region is extended. Pointy theories of space and space-time—such as Euclidean space or Minkowski space—are the kind that figure in modern physics. A rival tradition, most famously associated in the last century with A. N. Whitehead, instead embraces gunk.2 On the Whiteheadian view, points, curves and surfaces are not parts of space, but rather abstractions from the true regions. Three different motivations push philosophers toward gunky space. The first is that the physical space (or space-time) of our universe might be gunky. We posit spatial reasons to explain what goes on with physical objects; thus the main reason..

Relativistic quantum theories are equipped with a background Minkowski spacetime and non-relativistic quantum theories with a Galilean space-time. Traditional investigations have distinguished their distinct space-time structures and have examined ways in which relativistic theories become sufficiently like Galilean theories in a low velocity approximation or limit. A different way to look at their relationship is to see that both kinds of theories are special cases of a certain five-dimensional generalization involving no limiting procedures or approximations. When one compares them, striking features emerge that bear on philosophical questions, including the ontological status of the wave function and time reversal invariance.

This volume is dedicated to the centennial anniversary of Minkowski's discovery of spacetime.

Extending on an earlier paper [Found. Phys. Ltt., 16(4) 343–355, (2003)], it is argued that instants of time and the instantaneous (including instantaneous relative position) do not actually exist. This conclusion, one which is also argued to represent the correct solution to Zeno’s motion paradoxes, has several implications for modern physics and for our philosophical view of time, including that time and space cannot be quantized; that contrary to common interpretation, motion and change are compatible with the “block” universe and relativity; and that time, space, and space-time too, cannot exist. Instead, motion and change become the major players.

Einstein's special theory, as interpreted by Herman Minkowski, suggests that an understanding of space and time requires the replacement of three-dimensional space and one dimensional time with a four-dimensional spacetime continuum, as a natural kind of thing with a characteristic, geometrical, structure. Issues of space and time in general, and of special relativity in particular, are not addressed in Bhaskar's A Realist Theory of Science , and their treatment in subsequent realist writings has been patchy and indecisive. Some of Bhaskar's observations in later writings, including his defence of fundamental ontological asymmetries between space and time, and between present, past and future, appear incompatible with a relativistic perspective. Equally problematic, from a critical realist perspective, is the apparent ontological prioritisation of events, and causation as action-by-contact, within the Minkowski interpretation of special relativity. This paper argues that the four-dimensional spacetime continuum of special relativity occupies its own level at the base of the ontological hierarchy of natural kinds, providing lower-order components and laws for higher-order physical, chemical, biological and social structures. While providing no definitive reconciliation of relativistic and realist perspectives, this paper does suggest that A. N. Whitehead's idea of atomic events, or `actual occasions', could pave the way for some possible future reconciliation.

It is argued that Minkowski space-time cannot serve as the deep structure within a ``constructive'' version of the special theory of relativity, contrary to widespread opinion in the philosophical community.