Edward MacKinnon

Aristotele. Science as a systematic explanation through causes.--Newton, I. Rules and reflections on scientific reasoning.--Carnap, R. Empiricism, semantics, and ontology.--Hempel, C. On the logic of explanation.--Nagel, E. The realist view of theories.--Quine, W. V. On the role of logic in explanation.--Harris, E. E. Method and explanation in metaphysics.--Einstein, A. Remarks on Bertrand Russell's theory of knowledge.--Sellars, W. The language of theories.--MacKinnon, E. Atomic physics and reality.--Bunge, M. Physics and reality.--Heelan, P. A. Quantum mechanics and objectivity.--Bibliographical essay (p. 285-301).

This article probes the question of what interpretations of quantum mechanics actually accomplish. In other domains, which are briefly considered, interpretations serve to make alien systematizations intelligible to us. This often involves clarifying the status of their implicit ontology. A survey of interpretations of non-relativistic quantum mechanics supports the evaluation that these interpretations make a contribution to philosophy, but not to physics. Interpretations of quantum field theory are polarized by the divergence between the Lagrangian field theory that led to the Standard Model of Particle physics and the Algebraic quantum field theory, that discounts an ontology of particles. Ruetsche's interpretation, it is argued, offers a potential for loosening the sharp polarization that presently obtains. A brief evaluation focuses on the functional ontology of quantum field theory considered as an effective theory.

The idea that science aspires to and routinely achieves truths about the world has been challenged in recent writings. Rather than beginning with a theory of scientific development, or of scientific explanation, we begin with a consideration of truth claims in ordinary discourse, particularly with Davidson's truth-functional semantics. Next we consider the way in which some framework features of ordinary language discourse are extended to and modified in scientific discourse. Two areas are treated in more detail: quantum theory, and the peculiar problem of semantic entailment it involves; and quantum field theory. These supply a basis for criticizing some historicist and logicist treatments of the truth of scientific claims

The consistent histories reformulation of quantum mechanics was developed by Robert Griffiths, given a formal logical systematization by Roland Omn\`{e}s, and under the label `decoherent histories', was independently developed by Murray Gell-Mann and James Hartle and extended to quantum cosmology. Criticisms of CH involve issues of meaning, truth, objectivity, and coherence, a mixture of philosophy and physics. We will briefly consider the original formulation of CH and some basic objections. The reply to these objections, like the objections themselves, involves a mixture of physics and philosophy. These replies support an evaluation of the CH formulation as a replacement for the measurement, or orthodox, interpretation.

This article completes the study begun in I by a detailed consideration of errol harris's, "the foundations of metaphysics in science" and by an independent interpretation of the epistemological foundations of scientific theories. This is done in terms of two components labelled 'a physical language' and 'a mathematical language'. A physical language is conceived as a transformed extension of ordinary language which preserves its basic structural principles while modifying its descriptive metaphysics. The relation between such a physical language and a mathematical system is explained by a correspondence between second order physical predicates and first order mathematical predicates

An epistemological interpretation of quantum mechanics hinges on the claim that the distinctive features of quantum mechanics can be derived from some distinctive features of an observational basis. Old and new variations of this theme are listed. The program has a limited success in non-relativistic quantum mechanics. The crucial issue is how far it can be extended to quantum field theory without introducing significant ontological postulates. A C*-formulation covers algebraic quantum field theory, but not the standard model. Julian Schwinger’s anabatic methodology extended a strict measurement-based formulation of quantum mechanics through field theory. His extension also excluded the quark hypothesis and the standard model. Quarks and local gauge invariance are postulates that go beyond the limits of an epistemological interpretation of quantum mechanics. The ontological significance ascribed to these advances depends on the role accorded ontology.

In the course of his long development, Kant's concept of matter changed somewhat, while his concept of scientific explanation changed considerably. Both developments achieved a coherent integration in Kant's Metaphysical Foundations of Natural Science. Using this developmental background, the present paper argues that the Foundations should be interpreted as an attempted rational reconstruction of the mechanics of Newton and Euler. Kant attempted to do this by constructing a concept of matter that would confer a Leibnizian intelligibility on Newtonian mechanics, and also accord with Kant's theories on the nature of concepts and their role in scientific explanation.

The revolt against logical positivism within the philosophy of science has now lasted long enough to produce something of a counter-revolution. As the more strident charges (positivistic analyses misrepresent the most fundamental features of the scientific enterprise and have contributed little or nothing to its clarification) and counter-charges (any attempt to induce a philosophy of science from studies in the history of science rests on a massive genetic fallacy) gradually subside, critical interest is focussing on the presuppositions that guide and structure various interpretations of science. Here epistemological positions, often implicitly assumed, play a pivotal role. In the present article we shall try to make different positions and presuppositions explicit by examining some current developments in the philosophy of science. This examination will be focused on, though not limited to, three recent books by I. Schefller, S. Körner, and E. Harris.

One of the key interpretative problems generated by the development of quantum theory was the conceptual consistency underlying scientific change, a problem not adequately treated by any of the leading theories of scientific development. In different but related ways Quine, Sellars, and Davidson have treated the problem of conceptual consistency by showing how one can begin with ordinary language and proceed to specialized extensions. Their techniques have not been applied to modern physics. However, one basis for applying them arises from the deep similarities between some of the work of these analysts and the Copenhagen interpretation rightly interpreted. To make this more concrete three concepts whose meanings have changed as a result of scientific progress are considered: 'atom', 'state of a system', and 'particle'. Each functions in a different way and requires a different type of analysis.