In search of (spacetime) structuralism (original) (raw)

Substantivalism, relationism, and structural spacetime realism

Foundations of Physics, 2000

A historian of 20 th century philosophy of science that were to consider the recent renaissance of studies on the ontological status of spacetime would certainly notice a significant shift of interest toward metaphysical issues previously scorned by neopositivists philosophers. 2 Some philosophers more inclined toward historical analysis have complained about the audacious tendency of some contemporary philosophers of space and time to portray Newton and Leibniz (see Alexander 1956) as defenders of views that, like substantivalism and relationism, do not always represent in an accurate way the positions really taken by these historical figures (see . However, worse than such moderate forms of "interpretive violence" perpetrated on 17 th century natural philosophers -which in any case are not motivated by unfair attempts to add significance to one's pet philosophical problem by ennobling its historical pedigree -is the fact that the current participants to the debate don't even seem to agree about how to formulate "spacetime substantivalism" 3 within the fundamental spacetime theory of contemporary physics, the general theory of relativity. For example, it is not clear whether one should identify spacetime with the bare manifold or with the metric field. As is often the case when there is no agreement even about the nature of the problem, there is a natural tendency to affirm that 1 I want to thank Robert Rynasiewicz and Robert DiSalle for having read a previous version of this paper and having helped to remove some of my misinterpretations of their views. I am the only responsible for the remaining mistakes. 2 Such foundational studies were revived in the late eighties by the so-called "hole argument" due to John for discussions of the philosophical and metaphysical issues. The tendency to misrepresent Leibniz and Newton as defenders of relationism and substantivalism respectively was decisively more present in the philosophy of space and time of the first part of the century, and especially in Reichenbach.

Radical Structural Essentialism for the Spacetime Substantivalist

The Foundation of Reality: Fundamentality, Space, Time, 2020

Spacetime substantivalists insist that spatiotemporal points are fundamental entities and thus are ontologically independent from the physical objects occupying these points. In this essay I argue that the best metaphysical option for the substantivalist is to adopt a radical version of structural essentialism, according to which participation in a certain relational structure is both a necessary and sufficient condition of identity for the elements characterized by this structure. I compare my proposed variant of essentialism with some alternative conceptions, such as Tim Maudlin’s metric essentialism and David Glick’s Minimal Structural Essentialism. I discuss how my Radical Structural Essentialism deals with the challenge of the hole argument as well as some less well-known challenges, such as the problem of contingent counterfactuals regarding the material contents of spacetime, and the ‘mole’ argument. Later I explain why the structure consisting of the metric tensor is a genuinely relational structure, and I defend the claim that in order to preserve the identity of its elements the actual structure may be merely embeddable in (and not necessarily isomorphic with) an alternative structure.

On the ontology of spacetime: Substantivalism, relationism, eternalism, and emergence

I present a discussion of some issues in the ontology of spacetime. After a characterisation of the controversies among relationists, substantivalists, eternalists, and presentists, I offer a new argument for rejecting presentism, the doctrine that only present objects exist. Then, I outline and defend a form of spacetime realism that I call event substantivalism. I propose an ontological theory for the emergence of spacetime from more basic entities (timeless and spaceless ‘events’). Finally, I argue that a relational theory of pre-geometric entities can give rise to substantival spacetime in such a way that relationism and substantivalism are not necessarily opposed positions, but rather complementary. In an appendix I give axiomatic formulations of my ontological views.

The Substantivalist View of Spacetime Proposed by Minkowski and Its Educational Implications

The geometrical interpretation of general relativity provides the formalism with intuitive imagery (Chandler 1994). Such an interpretation often presupposes a substantival space: a space taken to be a real entity whose existence is independent of the matter contained. Nowadays an image of space-container seems to have wide acceptance among physicists. Special relativity is, however, usually still taught as the theory which overthrew Newton’s absolute concepts (among which is the idea of a space-container). This inconsistency is considered here. Special relativity can also be interpreted substantivally, as Minkowski did in 1908. His substantivalism is the key to laying out an internally coherent substantivalist line running from Newtonian mechanics to general relativity. Another plausible interpretative line, namely the ‘relationist line’, will be mentioned. It will allow us to conclude with remarks concerning the cultural and educational implications of a consistent interpretative apparatus organised in several interpretative lines.

Challenging the Spacetime Structuralist

Philosophy of Science, 2009

Structural realist interpretations of generally relativistic spacetimes have recently come to enjoy a remarkable degree of popularity among philosophers. I present a challenge to these structuralist interpretations that arises from considering cosmological models in general relativity. As a consequence of their high degree of spacetime symmetry, these models resist a structuralist interpretation. I then evaluate the various strategies available to the structuralist to react to this challenge.

Should we be Substantivalists or Relationalists about Spacetime in light of Contemporary Physics?

As a first pass, substantivalism about spacetime is the view that that space and time exist as fundamental entities, independently from and in addition to the matterorfields that populate them. Relationalism about spacetime states that space and time are (ultimately) emergent from or dependent upon other physical entities; such that facts about space and time are exhausted or fixed by the arrangement of matter. I very briefly elaborate on these competing views by situating them in their historical context. I then, in very sketchy terms, try to show that no clear distinction between the two views survives in modern physics. I suggest the dispute becomes a matter of linguistic convention.

Super-Relationism: Combining Eliminativism about Objects and Relationism about Spacetime

Philosophical Studies, 2016

I will introduce and motivate eliminativist super-relationism. This is the conjunction of relationism about spacetime and eliminativism about material objects. According to the view, the universe is a big collection of spatio-temporal relations and natural properties, and no substance (material or spatio-temporal) exists in it. The view is original since eliminativism about material objects, when understood as including not only ordinary objects like tables or chairs but also physical particles, is generally taken to imply substantivalism about spacetime: if properties are directly instantiated by spacetime without the mediation of material objects, then, surely, spacetime has to be a substance. After introducing briefly the two debates about spacetime (§1) and material objects (§2), I will present Schaffer's super-substantivalism (§3), the conjunction of substantivalism about spacetime and eliminativism about material objects at the fundamental level. I shall then expose and discuss the assumption from which the implication from eliminativism to substantivalism is drawn, and discuss the compatibility of eliminativism with relationism: if spacetime is not a substance, and if material objects are not real, how are we to understand the instantiation of properties (4§)? And what are the relata of spatio-temporal relations (5§)? I then show that each argument in favor of super-substantivalism offered by Schaffer also holds for super-relationism (§6) and examine several metaphysical consequences of the view (§7). I conclude that both super-substantivalism and super-relationism are compatible with Schaffer's priority monism (§8).