Alberto Cordero

Recent attempts to turn Standard Quantum Theory into a coherent representational system have improved markedly over previous offerings. Important questions about the nature of material systems remain open, however, as current theorizing effectively resolves into a multiplicity of incompatible statements about the nature of physical systems. Specifically, the most cogent proposals to date land in effective empirical equivalence, reviving old anti-realist fears about quantum physics. In this paper such fears are discussed and found unsound. It is argued that nothing of global skeptical or agnostic significance follows from the kind of underdetermination presently encountered in fundamental quantum theory. The case is instructive, however, for what it shows about the characteristics and prospects of scientific realism as a perspective in contemporary philosophy of science.

Las interpretaciónes de la física cuántica de Everett-DeWitt hablan de una multiplicidad de mundos físicamente coexistenrtes. Éstas imaginativas reacciones a los problemas conceptuales de la mecánica cuántica estándar forman una família de propuestas de “universos múltiples” que, sin pleno éxito, han sido tachadas de incoherentes.Everett-DeWitt interpretations of quantum physics speak of a multiplicity of physically coexisting worlds. These imaginative reactions to the conceptual problems of standard quantum mechanics form a family of physicalist “many-worlds” proposals that have been variously dismissed as “incoherent”, so far without full success. A renewed charge by Hilary Putnam now seems to pose deeper trouble for PMW. In a recent paper, he seizes on “Schrödinger’s cat” situations to expose how PMW relativization of actuality and basic combinatorics jointly ruin probabilistic talk. Putnam focuses on confirmation and luck. His case against PMW is thought-provoking but also questionable, or so I suggest in this paper. First I argue that, as presented, Putnam’s charge doesn’t go through. I then consider his argument proper. According to Putnam, experimental DeWittians must count themselves as “lucky” in a seriously incoherent sense. I consider his take on “luck” and deny that defenders of PMW need to so regard themselves. Although extravagant, their position cannot be fruitfully dismissed as incoherent on metascientific grounds. Indeed it attests to the way science rationally helps the imagination to grow.

This paper examines some physical sources of the concept of objective state reduction in quantum mechanics. Using case studies from nuclear physics and quantum chemistry, the question of whether one can induce a collapse theory from the practices of scientists working on specific problems is considered. A specific proposal is explored, with emphasis on such features as coherence, testability, unifying power and fertility. It is shown that, contrary to recent suggestions by David Albert, collapse theories are philosophically promising developments worthy of further study. Some philosophical implications of the development of collapse theories are discussed

The success of a scientific theory T is not an all-or-nothing matter; nor is a theory something one can usually accept or reject in toto (i.e. one may take T as being "approximately true", or take as true just certain "parts" of it, without necessarily affirming every posit and claim specific to T as being either completely right or completely wrong). This, however, raises questions about precisely which parts of T deserve to be taken as approximately true. on the basis of its success. A line of thinkers, particularly Kitcher, Leplin and Psillos, variously look for parts of a theory they can claim to have been "essentially" implicated in its distinctivesuccess, which they regard as primary candidates for realist truth ascription. But, how is one to determine which parts of any theory are "central" or "peripheral", "essential" or "idle" in the required sense? Attempts at spelling out relevant synchronic links between successful predictions and correct partial theorizing increasingly look like a misguided effort. As an alternative, this paper proposes a weaker, but arguably powerful enough, version of the realist relation between success and truth. Focusing on a pivotal case study in recent debates between realists and anti-realists (the conceptual changes undergone by theories oflight in the 19th century), a promising link between success and partial theoretical representation is located in the expansion and stabilization of approximately correct partial theoretical models of the theory's intended domain. The realist link is then formulated accordingly. In the resulting approach (a) predictive success is preserved as a marker of cumulative theoretical gain, but (b) specification of the latter is a diachronic rather than synchronic matter (i.e. gains become clear only after generations of theory change; specification of the particular loci of theoretical gain in connection with a given line of predictive success is not assumed to be generally possible at the time of the success in question). The truth ascriptions that get licensed are partial-of a piece-meal and retrospective sort, focused on methodologically specifiable theoretical subplots from past science.

Some thinkers distrust Darwinist explorations of complex human behaviors, particularly investigations into possible differences in valued skills between genders, races or classes. Such projects, it is claimed, tend to have adverse effects on people who are already disadvantaged. A recent argument by Philip Kitcher both clarifies and generalizes this charge to cover a whole genre of scientific projects. In this paper I try to spell out and analyze Kitcher's argument. The argument fails, I suggest, because some of its key premises fail to convince. My analysis focuses on relevant facts about the role of inquiry in fallibilist contexts, the texture of belief in contemporary natural science, and the moral dimension of scientific research

Summary: Responding to Laudan’s skeptical reading of history an influential group of realists claim that the seriously wrong claims past successful theories licensed were not really implicated in the predictions that once singled them out as successful. For example, in the case of Fresnel’s theory of light, it is said that although he appealed to the ether he didn’t actually need to in order to derive his famous experimental predictions—in them, we are assured, the ether concept was “idle,” “inessential,” “peripheral” or worse. This view, developed by J. Worrall and P. Kitcher in the 1980s and subsequently supplemented by J. Leplin and by S. Psillos has received critical attention in the literature over the last decade, but more needs to be said on the subject—or so I suggest in this paper. I bring forward four converging argumentative lines to show how and why, from the days of Fresnel to at least the decade after the Michelson-Morley experiments, the ether functioned and was understood as an “essential” posit in physics. My first line draws Fresnel’s actual deployment of the ether concept and the way he and his circle understood the achievements of his theory. The second line draws is from epistemological assessments of surprising implication in theories and its impact on leading theorists in the last two-thirds of the century. The third line draws from discussions of the optical ether in end-of-century reports circa 1900. The fourth focuses on entrenched metaphysical assumptions that persisted in the practice of physics until the advent of special relativity. Pulling these four lines together shows, I think, why attempts at synchronic identification of sound theory-parts are bound to fail, and also how realists might try to meet the challenge this creates

Although exceptionally successful in the laboratory, the standard version of quantum theory is marred as a realist-objectivist proposition because of its internal conceptual difficulties and its tension with important parts of physics—most conspicuously, relativity theory. So, to meet these challenges, in recent years at least three distinct major objectivist programs have been advanced to further quantum theory into a proper general account of material systems. Unfortunately, the resulting proposals turn out to be, for all practical purposes, empirically equivalent both among themselves and against the standard version. This paper analyzes the basic issues involved in the case. It is argued that (a) the global anti-realist conclusion derived from it are fallacious, and (b) the encountered underdetermination shows how contingent upon the state of empirical knowledge talk about the “limits of science” actually is.