Katherine Brading

Scientific Structuralism: Presentation and Representation

This paper explores varieties of scientific structuralism. Central to our investigation is the notion of ‘shared structure’. We begin with a description of mathematical structuralism and use this to point out analogies and disanalogies with scientific structuralism. Our particular focus is the semantic structuralist’s attempt to use the notion of shared structure to account for the theory‐world connection, this use being crucially important to both the contemporary structural empiricist and realist. We show why minimal scientific structuralism is, at the very least, a powerful methodological standpoint. Our investigation also makes explicit what more must be added to this minimal structuralist position in order to address the theory‐world connection, namely, an account of representation.

Which symmetry? Noether, Weyl, and conservation of electric charge

Abstract In 1918, Emmy Noether published a (now famous) theorem establishing a general connection between continuous ‘global’ symmetries and conserved quantities. In fact, Noethers paper contains two theorems, and the second of these deals with ‘local’ symmetries; prima facie , this second theorem has nothing to do with conserved quantities. In the same year, Hermann Weyl independently made the first attempt to derive conservation of electric charge from a postulated gauge symmetry. In the light of Noethers work, it is puzzling that Weyls argument uses local gauge symmetry. This paper explores the relationships between Weyls work, Noethers two theorems, and the modern connection between gauge symmetry and conservation of electric charge. This includes showing that Weyls connection is essentially an application of Noethers second theorem, with a novel twist.

Symmetries and invariances in classical physics

Symmetry, intended as invariance with respect to a transformation (more precisely, with respect to a transformation group), has acquired more and more importance in modern physics. This Chapter explores in 8 Sections the meaning, application and interpretation of symmetry in classical physics. This is done both in general, and with attention to specific topics. The general topics include illustration of the distinctions between symmetries of objects and of laws, and between symmetry principles and symmetry arguments (such as Curies principle), and reviewing the meaning and various types of symmetry that may be found in classical physics, along with different interpretative strategies that may be adopted. Specific topics discussed include the historical path by which group theory entered classical physics, transformation theory in classical mechanics, the relativity principle in Einsteins Special Theory of Relativity, general covariance in his General Theory of Relativity, and Noethers theorems. In bringing these diverse materials together in a single Chapter, we display the pervasive and powerful influence of symmetry in classical physics, and offer a possible framework for the further philosophical investigation of this topic.

A Note on General Relativity, Energy Conservation, and Noether’s Theorems

The subject of this note has been a small historical thread in the long and complex story of the status of energy conservation in General Relativity, concerning two related claims made by Klein and Hilbert: that the energy conservation law is an identity in generally covariant theories, and that this marks a contrast with other (earlier) theories. Both these claims were disputed by Einstein. We have seen how three theorems proved by Noether and Klein can be brought to bear on this disagreement, showing that: (1) Klein’s worry over the physical significance of the energy conservation law in General Relativity was perhaps not adequately addressed by Einstein, even though in the end we side with Einstein against Klein, and (2) the possibility of re-writing the energy conservation law in the form that so worried Klein does indeed depend upon the local symmetry structure of General Relativity.

Autonomous Patterns and Scientific Realism

Taking Bogen and Woodwards discussion of data and phenomena as his starting point, McAllister presents a challenge to scientific realism. I discuss this challenge and offer a suggestion for how the scientific realist could respond to both its epistemic and ontological aspects. In so doing, I urge that the scientific realist should not reject ontological pluralism from the start, but should seek to explore versions of scientific realism that leave open the possibility of certain kinds of pluralist ontology. I investigate the available options (in terms of foundationalism, reductionism, and universalism) and use a law-constitutive approach to offer a strategy for the scientific realist who is open-minded about ontological pluralism.

Underdetermination as a Path to Structural Realism

We examine the argument for ontic structural realism that begins from an alleged “metaphysical underdetermination” afflicting contemporary fundamental physics. Current discussions have focussed on challenging this underdetermination claim. Our purpose here is to examine what follows even if the premise concerning underdetermination is conceded. We consider the additional premises needed to arrive at an endorsement of ontic structural realism, and show that each can and should be rejected. Moreover, the ontic structural realist program faces an analogous metaphysical underdetermination issue of its own. We conclude that the argument fails, independently of whether the alleged metaphysical underdetermination is conceded.

Epistemic Structural Realism and Poincaré’s Philosophy of Science

Recent discussions of structuralist approaches to scientific theories have stemmed primarily from John Worrall’s “Structural Realism” in which he defends a position (since characterized “epistemic structural realism”) whose historical roots he attributes to Poincaré. In the renewed debate inspired by Worrall, it is thus not uncommon to find Poincaré’s name associated with various structuralist positions. However, Poincaré’s structuralism is deeply entwined with neo-Kantianism and the roles of convention and objectivity within science. In this article we explore the nature of these dependencies. What emerges is not only a clearer picture of Poincaré’s position regarding structuralism but also two arguments for versions of epistemic structuralism different in kind from that of Worrall.

DON ROSS, JAMES LADYMAN, and HAROLD KINCAID (eds) Scientific Metaphysics

What is ‘scientific metaphysics’, and why might we need such a thing? There is no univocal answer to be found among the pages of this volume. Rather, this collection should be regarded as an attempt to probe the sources of dissatisfaction many philosophers of science feel with respect to contemporary analytic metaphysics and to offer concrete proposals on how these might be addressed. This reaction against analytic metaphysics is not a neo-positivist dismissal of metaphysical concepts as meaningless; on the contrary, the reaction comes not least from metaphysically inclined philosophers. Chakravartty (Chapter 2) argues that any philosopher of science with minimal realist commitments will inevitably find herself dealing with concepts (such as properties, causation, laws of nature, de re modality, and so forth) whose analysis seems far removed from the details of scientific practice and which lead her into engagement with metaphysical theorizing. But when turning to the metaphysical literature, the philosopher of science most often does not find what she is looking for, despite the apparent overlap of subject matter between philosophy of science and metaphysics; frustration with contemporary analytic metaphysics sets in. The problems seem to arise from the questions and methodologies that dominate contemporary analytic metaphysics, and a closer look at these perceived problems helps to shed light on the motivations that generate a call for a different kind of metaphysics: a ‘scientific metaphysics’. Although all philosophers rely on intuitions and empirical input in order to reason about the world, several authors in this volume argue that the Brit. J. Phil. Sci. 65 (2014), 899–903

Presentism as an Empirical Hypothesis

Within philosophy of physics it is broadly accepted that presentism as an empirical hypothesis has been falsified by the development of special relativity. In this article, I identify and reject an assumption common to both presentists and advocates of the block universe and then offer an alternative version of presentism that does not begin from spatiotemporal structure, which is an empirical hypothesis, and which has yet to be falsified. While some features of familiar presentism are lost, a sufficient core remains to warrant the label (though I fear that labeling it “presentism” dooms the view).