A stalwart view in the philosophy of science holds that, even when broadly construed so as to include theoretical auxiliaries, theories cannot make direct contact with observations. This view owes much to Bogen and Woodward’s influential distinction between data and phenomena. According to them, data are typically the kind of things that are observable or measurable like "bubble chamber photographs, patterns of discharge in electronic particle detectors and records of reaction times and error rates in various psychological experiments". Phenomena are (...) physical processes that are typically unobservable. Examples of the latter category include "weak neutral currents, the decay of the proton, and chunking and recency effects in human memory". Theories, in Bogen and Woodward’s view, are utilised to systematically explain, infer and predict phenomena, not data. The relationship between theories and data is rather indirect. Data count as evidence for phenomena and the latter in turn count as evidence for theories. This view is becoming increasingly influential, Stathis Psillos and Mauricio Suárez ). In this paper I argue contrary to this view that in various significant and well-known cases theories do make direct contact with the help of suitable auxiliaries. (shrink)

In this paper I develop five worries concerning Cartwright’s realism about entities and capacities. The first is that while she was right to insist on the ontic commitment that flows from causal explanation, she was wrong to tie these commitments solely to the entities that do the causal explaining. This move obscured the nature of causal explanation and its connection to laws. The second worry is that when she turned her attention to causal inference, by insisting on the motto of (...) ‘the most likely cause’, she underplayed her powerful argument for realism. For she focused her attention on an extrinsic feature of causal inference (or, indeed, of any ampliative inference), that is the demand of high probability, leaving behind the intrinsic qualities that causal explanation should have in order to provide the required understanding. The third worry is that her objections to Inference to the Best Explanation were unnecessarily tied to her objections about the falsity of fundamental laws. The fourth worry is that though her argument for positing capacities and being realist about them was supposed to take strength from its parallel with Sellars’s powerful argument for the indispensable explanatory role of positing unobservable entities, there are important disanalogies between the two arguments which cast doubt on the indispensability of capacities. The final (fifth) worry is that laws—perhaps brute regularities—might well have to come back from the front door, since they are still the most plausible candidates for explaining why objects have the capacities to do what they can do. (shrink)

According to conventional wisdom, local gauge symmetry is not a symmetry of nature, but an artifact of how our theories represent nature. But a study of the so-called theta-vacuum appears to refute this view. The ground state of a quantized non-Abelian Yang-Mills gauge theory is characterized by a real-valued, dimensionless parameter theta—a fundamental new constant of nature. The structure of this vacuum state is often said to arise from a degeneracy of the vacuum of the corresponding classical theory, which degeneracy (...) allegedly arises from the fact that “large” (but not “small”) local gauge transformations connect physically distinct states of zero field energy. If that is right, then some local gauge transformations do generate empirical symmetries. In defending conventional wisdom against this challenge I hope to clarify the meaning of empirical symmetry while deepening our understanding of gauge transformations. I distinguish empirical from theoretical symmetries. Using Galileo’s ship and Faraday’s cube as illustrations, I say when an empirical symmetry is implied by a theoretical symmetry. I explain how the theta-vacuum arises, and how “large” gauge transformations differ from “small” ones. I then present two analogies from elementary quantum mechanics. By applying my analysis of the relation between empirical and theoretical symmetries, I show which analogy faithfully portrays the character of the vacuum state of a classical non-Abelian Yang-Mills gauge theory. The upshot is that “large” as well as “small” gauge transformations are purely formal symmetries of non-Abelian Yang-Mills gauge theories, whether classical or quantized. It is still worth distinguishing between these kinds of symmetries. An analysis of gauge within the constrained-Hamiltonian formalism yields the result that “large” gauge transformations should not be classified as gauge transformations; indeed, nor should “global” gauge transformations. In a theory in which boundary conditions are modeled dynamically, “global” gauge transformations may be associated with physical symmetries, corresponding to translations of these extra dynamical variables. Such translations are symmetries if and only if charge is conserved. But it is hard to argue that these symmetries are empirical, and in any case they do not correspond to any constant phase change in a quantum state. (shrink)

RÉSUMÉDans cette contribution, les points fondamentaux du livre d'Anjan Chakravartty, Scientific Ontology, sont discutés de manière critique. Après une brève présentation du projet d'une ontologie dite «stance-based», je critique la manière dont Chakravartty conçoit l'inférence métaphysique. Puis, dans la section 4, je conteste l'opinion de Chakravartty selon laquelle les débats fondamentaux en métaphysique conduisent inévitablement à un désaccord insoluble. La section 5 examine le concept de position épistémique et relève les problèmes inhérents à la manière dont Chakravartty conçoit la rationalité (...) de la sélection d'une position. Finalement, la section 6 concerne les implications d'une ontologie qui serait basée sur les positions épistémiques pour le débat sur le réalisme scientifique. (shrink)

This chapter relocates the debate about the theoretical virtues to the empirical level and argues that the question of whether the virtues (and what virtues, if any) have epistemic import is best answered empirically, through an examination of actual scientific theories and hypotheses in the history of science. As a concrete example of this approach, the chapter discusses a case study from the mid-nineteenth-century debate about the transmissibility of puerperal fever. It argues that this case shows that the virtues are (...) at least sometimes epistemic, but also that neither scientific realists nor anti-realists get it quite right: the virtues, even if epistemic, are not necessarily truth-conducive, but neither are they merely pragmatic. It also argues that the discussion of puerperal fever shows that the virtue question, as it is currently featured in the scientific realism debate, ought to be reformulated. We should examine not just whether a given scientific theory has virtues or not, but rather how debates among competing theories, all of which have some virtues, get resolved. (shrink)

In a recent paper James Bogen and James Woodward denounce a set of views on confirmation that they collectively brand 'IRS'. The supporters of these views cast confirmation in terms of Inferential Relations between observational and theoretical Sentences. Against 1RS accounts of confirmation, Bogen and Woodward unveil two main objections: (a) inferential relations are not necessary to model confirmation relations since many data are neither in sentential form nor can they be put in such a form and (b) inferential relations (...) are not sufficient to model confirmation relations because the former cannot capture evidentially relevant factors about the detection processes and instruments that generate the data. In this paper I have a two-fold aim: (i) to show that Bogen and Woodward fail to provide compelling grounds for the rejection of IRS models and (ii) to highlight some of the models' neglected merits. (shrink)

This paper challenges the appeal to theory virtues in theory choice as well as the appeal to the intellectual and moral virtues of an agent as determining unique choices between empirically equivalent theories. After arguing that theoretical virtues do not determine the choice of one theory at the expense of another theory, I argue that nor does the appeal to intellectual and moral virtues single out one agent, who defends a particular theory, and exclude another agent defending an alternative theory. (...) I analyse Duhem’s concept of good sense and its recent interpretation in terms of virtue epistemology. I argue that the virtue epistemological interpretation does not show how good sense leads to conclusive choices and scientific progress. (shrink)

There has been an empiricist tradition in the core of Logical Positivism/Empiricism, starting with Moritz Schlick and ending in Herbert Feigl (via Hans Reichenbach), according to which the world of empiricism need not be a barren place devoid of all the explanatory entities posited by scientific theories. The aim of this paper is to articulate this tradition and to explore ways in which its key elements can find a place in the contemporary debate over scientific realism. It presents a way (...) empiricism can go for scientific realism without metaphysical anxiety, by developing an indispensability argument for the adoption of the realist framework. This argument, unlike current realist arguments, has a pragmatic ring to it: there is no ultimate argument for the adoption of the realist framework. (shrink)

Are theories ‘underdetermined by the evidence’ in any way that should worry the scientific realist? I argue that no convincing reason has been given for thinking so. A crucial distinction is drawn between data equivalence and empirical equivalence. Duhem showed that it is always possible to produce a data equivalent rival to any accepted scientific theory. But there is no reason to regard such a rival as equally well empirically supported and hence no threat to realism. Two theories are empirically (...) equivalent if they share all consequences expressed in purely observational vocabulary. This is a much stronger requirement than has hitherto been recognised— two such ‘rival’ theories must in fact agree on many claims that are clearly theoretical in nature. Given this, it is unclear how much of an impact on realism a demonstration that there is always an empirically equivalent ‘rival’ to any accepted theory would have—even if such a demonstration could be produced. Certainly in the case of the version of realism that I defend—structural realism—such a demonstration would have precisely no impact: two empirically equivalent theories are, according to structural realism, cognitively indistinguishable. (shrink)