Relying on the notion of “overlapping perspectives,” this paper argues that entity realism and perspectivism are complementary. According to entity realism, it is justified to maintain a positive attitude toward the existence of unobservable entities with which multiple experimental interactions are possible. Perspectivism also explains that our beliefs about these entities are bounded by historically contingent theoretical and instrumental perspectives. The argument of the paper is developed through a discussion of Ronald Giere’s versions of realism: entity realism, constructive realism, and (...) perspectival realism. (shrink)

Inspired by Bas van Fraassen’s Stance Empiricism, Anjan Chakravartty has developed a pluralistic account of what he calls epistemic stances towards scientific ontology. In this paper, I examine whether Chakravartty’s stance pluralism can exclude epistemic stances that licence pseudo-scientific practices like those found in Scientology. I argue that it cannot. Chakravartty’s stance pluralism is therefore prone to a form of debilitating relativism. I consequently argue that we need (1) some ground or constraint in relation to which epistemic stances can be (...) ranked by degrees, and (2) some way to demarcate science from pseudo-science so that we know what epistemic stances are about. Regarding (1), I argue that empirical detectability can serve as the ground in relation to which epistemic stances are ranked by degrees. Regarding (2), I argue for ranking sciences on a continuum according to established institutional criteria, rather than attempting to draw a strict demarcation. (shrink)

My target is the epistemological dimension of the realism debate. After establishing a stance voluntarist framework with a Jamesian background, drawing mostly on Wylie, Chakravarty, and van Fraassen, I argue that current voluntarists are too permissive. I show that especially various anti-realist stances but also some realist and selective realist stances block themselves from refutation by the history of science. I argue that such stances should be rejected. Finally, I propose that any disagreement that cannot be resolved by this strategy (...) frequently boils down to an epistemic value disagreement about balancing the truth-goal. (shrink)

In this paper, we first examine the reasons for opposing metaphysics. While assessing these reasons, we intend to reach a plausible stance regarding the relationship between science and metaphysics and its role and importance in scientific activity. There are different views on this old question. We argue that the interaction of metaphysics and science is a complex interaction that can only be defended in the light of a critical approach. In this critical attitude, one should not only pay attention to (...) the role and importance of metaphysics in science but also should have an epistemic humility about his expectations of it. (shrink)

This dissertation is about human knowledge of reality. In particular, it argues that scientific knowledge is bounded by historically available instruments and theories; nevertheless, the use of several independent instruments and theories can provide access to the persistent potentialities of reality. The replicability of scientific observations and experiments allows us to obtain explorable evidence of robust entities and properties. The dissertation includes seven chapters. It also studies three cases – namely, Higgs bosons and hypothetical Ϝ-particles (section 2.4), the Ptolemaic and (...) Kepler model of the planets (section 6.7), and the special theory of relativity (chapter 7). -/- Chapter 1 is the introduction of the dissertation. Chapter 2 clarifies the notion of the real on the basis of two concepts: persistence and resistance. These concepts enable me to explain my ontological belief in the real potentialities of human-independent things and the implications of this view for the perceptual and epistemological levels of discussion. On the basis of the concept of “overlapping perspectives”, chapter 3 argues that entity realism and perspectivism are complementary. That is, an entity that manifests itself through several experimental/observational methods is something real, but our knowledge of its nature is perspectival. Critically studying the recent views of entity realism, chapter 4 extends the discussion of entity realism and provides a criterion for the reality of property tokens. Chapter 5, in contrast, develops the perspectival aspects of my view on the basis of the phenomenological-hermeneutical approaches to the philosophy of science. This chapter also elaborates my view of empirical evidence, as briefly expressed in sections 2.5 and 4.5. Chapter 6 concerns diachronic theoretical perspectives. It first explains my view of progress, according to which current perspectives are broader than past ones. Second, it argues that the successful explanations and predictions of abandoned theories can be accounted for from our currently acceptable perspectives. The case study of Ptolemaic astronomy supports the argument of this chapter. Chapter 7 serves as the conclusion of the dissertation by applying the central themes of the previous chapters to the case study of special relativity theory. I interpret frame-dependent properties, such as length and time duration, and the constancy of the speed of light according to realist perspectivism. (shrink)

The anti-metaphysical argument against scientific realism is the following: Knowledge of unobservable entities implies metaphysical knowledge; There is no metaphysical knowledge. Therefore, there is no knowledge of unobservable entities. This argument has strangely received little attention in the profuse literature on scientific realism. This paper claims that the AMA is logically more fundamental than both the pessimistic meta-induction and the underdetermination argument. The second and main claim of this paper is that the instrumentalists’ use of AMA is incoherent. The gist (...) of my argument is that experimental knowledge requires minimally metaphysical knowledge, and that minimally metaphysical knowledge—when associated with empirical knowledge—suffices to yield a minimal knowledge of the unobservable. I then examine and reject two possible responses: minimally metaphysical instrumentalism and algebraic instrumentalism. (shrink)

I want to combine two hitherto largely independent research projects, scientific understanding and mechanistic explanations. Understanding is not only achieved by answering why-questions, that is, by providing scientific explanations, but also by answering what-questions, that is, by providing what I call scientific descriptions. Based on this distinction, I develop three forms of understanding: understanding-what, understanding-why, and understanding-how. I argue that understanding-how is a particularly deep form of understanding, because it is based on mechanistic explanations, which answer why something happens in (...) virtue of what it is made of. I apply the three forms of understanding to two case studies: first, to the historical development of thermodynamics and, second, to the differences between the Clausius and the Boltzmann entropy in explaining thermodynamic processes. (shrink)

Nonrelativistic quantum mechanics (QM) works perfectly well for all practical purposes. Once one admits, however, that a successful scientific theory is supposed not only to make predictions but also to tell us a story about the world in which we live, a philosophical problem emerges: in the specific case of QM, it is not possible to associate with the theory a unique scientific image of the world; there are several images. The fact that the theory may be compatible with distinct (...) ontologies, and that those ontologies may themselves be associated with a plurality of metaphysical approaches, gives rise to the problem of metaphysical underdetermination. This paper concludes that the available metametaphysical criteria fail to deliver objectivity in theory choice, and it puts forward its own criterion based on a tension between two methods of metaphysical inquiry: one that is closely related to science and another that is not. (shrink)

The article focuses on the unifying and explanatory power of the selective realism defended by Anjan Chakravartty. Our main aim is twofold. First, we critically analyse the purported synthesis between entity realism and structural realism offered by the author. We give reasons to think that this unification is an inconvenient marriage. In the second step, we deal with certain controversial aspects of the intended unification among three metaphysical concepts: causation, laws of nature and natural kinds. After pointing out that Chakravartty’s (...) conception of laws is a plausible view that a scientific realist might endorse, we contend, on the contrary, that the concept of natural kind is dispensable in the framework of Chakravartty’s realism. (shrink)

In this paper I defend the claim that Paul Feyerabend held a robust metaphilosophical position for most of his philosophical career. This position I call Decision-Based Epistemology and reconstruct it in terms of three key components: a form of epistemic voluntarism concerning the justification of philosophical positions and a behaviorist account of philosophical beliefs, which allows him to cast normative arguments concerning philosophical beliefs in scientific methodology, such as realism, in terms of means-ends relations. I then introduce non-naturalist and naturalist (...) variants of his conception of normativity, which I trace back to his mentors Viktor Kraft and Karl Popper, respectively. This distinction, introduced on the metaphilosophical level, can can be put to use to explain key changes in Feyerabend’s philosophical proposals, such as the viability of his methodological argument for realism. I conclude that this Decision-Based Epistemology should be further explored by historically embedding Feyerabend’s metaphilosophy in a voluntarist tradition of scientific philosophy. (shrink)

Book Review K. Brad Wray: Resisting Scientific Realism. Cambridge University Press: Cambridge 2018, xii + 224 pp, £ 75.00 (Hardcover), ISBN: 9781108231633. By Ragnar van der Merwe. In The Journal for the General Philosophy of Science.

There is an ongoing methodological debate in philosophy of science concerning the use of case studies as evidence for and/or against theories about science. In this paper, I aim to make a contribution to this debate by taking an empirical approach. I present the results of a systematic survey of the PhilSci-Archive, which suggest that a sizeable proportion of papers in philosophy of science contain appeals to case studies, as indicated by the occurrence of the indicator words “case study” and/or (...) “case studies.” These results are confirmed by data mined from the JSTOR database on research articles published in leading journals in the field: Philosophy of Science, the British Journal for the Philosophy of Science (BJPS), and the Journal for General Philosophy of Science (JGPS), as well as the Proceedings of the Biennial Meeting of the Philosophy of Science Association (PSA). The data also show upward trends in appeals to case studies in articles published in Philosophy of Science, the BJPS, and the JGPS. The empirical work I have done for this paper provides philosophers of science who are wary of the use of case studies as evidence for and/or against theories about science with a way to do philosophy of science that is informed by data rather than case studies. (shrink)

In this paper, I argue that stance voluntarism is a coherent and useful view for understanding debates about the ontological commitments warranted by science. To do so, I first engage in a defensive move: I rescue stance voluntarism from what I take to be the most pressing objection to have emerged in recent literature, which I call the ‘irrationality objection’. According to this objection, an agent courts irrationality by simultaneously holding an epistemic stance and believing that stance voluntarism is true. (...) I argue that this objection is based on a misunderstanding of stance voluntarism and the kinds of reasons that agents take themselves to have for their adopted stances. I then make the positive contention that we can expect the idea of stance voluntarism, thus saved, to not only be a defensible, but also a useful framework for understanding ontological disputes within science. I do this by presenting a case study from contemporary cosmology in which it is so. Combining these two claims, I argue that stance voluntarism is a coherent and useful view for understanding some ongoing disputes about ontology within scientific contexts. (shrink)

Since the publication of his seminal monograph "The scientific image", Bas van Fraassen is a key figure in philosophy of science. In this book, other philosophers with various outlooks critically discuss his work on theories, empiricism and philosophical stances. The book starts with a new article by van Fraassen on his preferred account of theories, the so-called semantic view. This account is now 50 years old, and van Fraassen takes this anniversary as an opportunity to review the account, its history (...) and the philosophical discussion about it. In the main part of the book, Nancy Cartwright, Finnur Dellsén, Matthias Egg, Steven French, Michael Friedman, Milena Ivanova and Michela Massimi discuss van Fraassen's contributions to philosophy. Three chapters focus on his engagement with realism (French, Friedman, Ivanova). Others study his voluntarism (Cartwright) and his view on representation (Massimi). Finally, there are contributions about his elaboration of empiricism (Dellsén) and his proposal to consider philosophical positions as stances (Egg). The volume includes a laudatio written by Steven French and finishes with a reply by van Fraassen to his critics. (shrink)

According to one prominent view, current metaphysics is hopelessly disconnected from the implications of modern science and as a result should be abandoned forthwith (Ladyman and Ross 2007). Others have taken a more conciliatory stance, suggesting that the metaphysicians’ toolbox may yet yield devices that could prove useful to the philosopher of science (French and McKenzie 2012). In this book, Sider aims to contribute to the metaphysics of science by setting out an array of such tools and indicating which are (...) up to the job. More particularly, he wants to demonstrate the usefulness of certain ‘postmodal’ concepts, such as fundamentality, which is a promising tack, given that (Callender 2011), for example, has argued that it was the modal turn initiated by the likes of Kripke that is ultimately responsible for the disconnect. To illustrate his overall claim that the tools we deploy may help frame the issues that we take to be central to the metaphysics of science, Sider chooses to analyse various forms of structuralism, the view that we should take structure to be primary and the relevant entities to be secondary : nomic essentialism, which takes properties to be ‘bound up’ with laws (ibid., p. 23); structural realism, which holds, in its epistemic form, that all that we know about the world is its structure and, in the ontic alternative, that the world is, in some sense, structure; and comparativism about quantities, whereby quantities are ascribed to objects comparatively or relationally (ibid., p. 122). His conclusions are that no postmodal sense can be made of the first two, and so much the worse for them, whereas comparativism about quantities can unproblematically be stated in such terms (ibid., p. 119), and indeed, when it comes to ‘fundamentality’, at least, may well be this concept’s ‘Waterloo’ (ibid., p. 166). The worry some philosophers of science will have is that Sider’s arguments are driven more by his metaphysics than the relevant science and the issues that he identifies don’t quite map onto those they take to be central. (shrink)

Recent contributions to the philosophy of the social sciences have motivated ontological commitments using appeals to the social sciences (_naturalized_ social ontologies). These arguments rely on social scientific realism about the social sciences, the view that our social scientific theories are approximately true. I apply a distinction formulated in metaontology between ontologically loaded and unloaded meanings of existential quantification to argue that there is a pragmatic approach to naturalized social ontology that is minimally realist (it treats existence claims as true (...) or false) but that is ontologically austere. I argue that the extant arguments may be construed in terms of this pragmatic approach. The result is an approach to social ontology that is deflationist about naturalized social ontology. (shrink)

Debates about scientific realism are closely connected to almost everything else in the philosophy of science, for they concern the very nature of scientific knowledge. Scientific realism is a positive epistemic attitude toward the content of our best theories and models, recommending belief in both observable and unobservable aspects of the world described by the sciences. This epistemic attitude has important metaphysical and semantic dimensions, and these various commitments are contested by a number of rival epistemologies of science, known collectively (...) as forms of scientific antirealism. This article explains what scientific realism is, outlines its main variants, considers the most common arguments for and against the position, and contrasts it with its most important antirealist counterparts. (shrink)

ABSTRACTMetaphysics has a problem with plurality: in many areas of discourse, there are too many good theories, rather than just one. This embarrassment of riches is a particular problem for metaphysical realists who want metaphysics to tell us the way the world is and for whom one theory is the correct one. A recent suggestion is that we can treat the different theories as being functionally or explanatorily equivalent to each other, even though they differ in content. The aim of (...) this paper is to explore whether the notion of functionally equivalent theories can be extended and utilized in the defence of metaphysical realism, drawing upon themes from structuralism in the philosophies of mathematics and science in which the specifics of theories do not matter as long as the relations in which they stand to other theories are maintained. I argue that despite its initial attractiveness, there are significant difficulties with this proposal. Discovering these obstacles thwarts the realist structuralist project, but reveals interesting features of metaphysical systems. (shrink)

Naturalized metaphysics aims to establish justified metaphysical claims, where metaphysics is meant to carry its usual significance, while avoiding the traditional methods of metaphysics—a priori reasoning, conceptual analysis, intuitions, and common sense—which naturalized metaphysics argues are not epistemically probative. After offering an explication of what it means to do metaphysics, this paper argues that naturalized metaphysics, at the outset, is hospitable to doing metaphysics. The underdetermination of metaphysics by science, however, changes the picture. Naturalized metaphysics has to break this underdetermination, (...) but the criticism of the traditional methods of metaphysics leaves no resources with which to do so. Naturalized metaphysics must therefore be more restrictive than originally intended to ensure that some metaphysical features avoid underdetermination. In this restrictive naturalized metaphysics, however, metaphysicians are only left the task of surveying the opinions of scientists which, it is argued, does not qualify as doing metaphysics. Thus, to fulfill its promise to save metaphysics, naturalized metaphysics displaces the metaphysician. Furthermore, the attempt to re-employ them via the principle of naturalistic closure is argued to fail. Metaphysicians should therefore not be happier with naturalized metaphysics than they are with the more explicitly eliminative trends in contemporary metametaphysics, such as neo-Carnapian deflationism, despite the promise of naturalized metaphysics, likely to Carnap’s dismay, to deliver justified claims about ultimate reality. (shrink)

Among scientific realists and anti-realists, there is a well-known, perennial dispute about the reality and knowability of unobservable objects. This dispute is also present among structural realists, who all agree that science gives us genuine knowledge of structure at the unobservable level (however that structure may be understood). Ontic structural realists reduce or eliminate the ontological role of objects, while epistemic structural realists argue that objects do or might exist but are unknowable. In part because ontic structural realism has some (...) evidence from quantum mechanics and the consequent underdetermination of the metaphysics of objects in its favor, the majority of contemporary structural realists adopt that view. In contrast, I argue that epistemic structural realism is a highly compelling view, particularly in the form that remains agnostic about unobservable objects. This view can remain consistent with the empirical data from quantum mechanics, can give a satisfactory account of the metaphysics of structure, and can distinguish itself from other extant versions of realism. I provide two arguments in favor of agnosticism about objects, the first of which argues that suspending belief is consistent with the impetus of naturalized metaphysics, and the second of which argues that agnosticism about objects is a rational response to reflection on the limits and aims of science. Thus, I show that agnostic epistemic structural realism is a defensible and compelling view in the philosophy of science that demands more attention in the literature. (shrink)

Most practitioners of the metaphysics of science agree that it should be a naturalized metaphysics. But, just as in other areas of philosophy, there is no consensus on what constitutes naturalism. Here I will focus on just one aspect, viz., the idea that the metaphysics of science should be epistemically naturalized. In the first section I will characterize the kind of epistemic naturalism relevant to the metaphysics of science. The main idea, drawing on the work of Penelope Maddy, is that (...) metaphysical inquiry is to be conducted and metaphysical claims justified in the very same way that scientific inquiry is conducted and scientific claims are justified. I then examine two prominent examples of metaphysicians of science proposing to “naturalize” the metaphysics of science, and argue that they fail to be epistemically natural. These are approaches due to James Ladyman and Don Ross, and to Anjan Chakravartty. Considering their failures shows us a way forward for naturalized metaphysics of science that is both more metaphysical and more scientific. (shrink)

The notion of natural kinds has been widely criticized in philosophy of science but also appears indispensable for philosophical engagement with classificatory practices. Rather than addressing this tension through a new definition of “natural kind”, this article suggests materiality as a substitute for naturalness in philosophical debates about scientific classification. It is argued that a theory of material kinds provides an alternative and more inclusive entry point for analyzing classificatory practices, which is specified through an account of “restricted malleability” of (...) materiality and further analyzed as (1) gradual, (2) multi-dimensional, (3) scalable, (4) interactive, and (5) purpose sensitive. (shrink)

While scientific pluralism enjoys widespread popularity within the philosophy of science, a related position, epistemic relativism, does not have much traction. Defenders of scientific pluralism, however, dread the question of whether scientific pluralism entails epistemic relativism. It is often argued that if a scientific pluralist accepts epistemic relativism, she will be unable to pass judgment because she believes that “anything goes”. In this article, I will show this concern to be unnecessary. I will also argue that common strategies to differentiate (...) relativism and pluralism fail. Building upon this analysis, I will propose a new way of looking at both positions’ relations. This article aims to understand what explains the friction between scientific pluralism and epistemic relativism. I will demonstrate that conceptualizing both epistemic relativism and scientific pluralism as “stances” sheds better light on their relation and demonstrates that it is, in principle, possible to support both positions at the same time. Preferred policies and levels of analysis, however, cause friction in practice. (shrink)

This article addresses Simon Lohse’s and Daniel Little’s responses to my article “Is Social Ontology Prior to Social Scientific Methodology?.” In that article, I present a pragmatic and deflationary view of the priority of social ontology to social science methodology where social ontology is valued for its ability to promote empirical success and not because it yields knowledge of what furnishes the social world. First, in response to Lohse, I argue that my view is compatible with a role for ontological (...) theorizing in the social sciences. However, the view that results instrumentalizes social ontology. Second, in my response to Little, I argue that the same considerations I made in my article apply to naturalistic attempts to motivate a non-deflationary view, repeating some of the central issues of that article. (shrink)

Some strongly empiricist views of scientific knowledge advocate a rejection of metaphysics. On such views, scientific knowledge is described strictly in terms of knowledge of the observable world, demarcated by human sensory abilities, and no metaphysical considerations need arise. This paper argues that even these views require some recourse to metaphysics in order to derive knowledge from experience. Central here is the notion of metaphysical inference, which admits of different “magnitudes”, thus generating a spectrum of putative knowledge with more substantially (...) empirical beliefs at one end, and more metaphysically imbued beliefs at the other. Given that metaphysical inference is required even concerning knowledge of the observable, the empiricist hope of avoiding metaphysics altogether is futile: knowledge of the observable simply involves metaphysical inferences that are of smaller magnitudes than others. Metaphysical inferences are required not only to distinguish veridical from non-veridical experience and to determine the quality of empirical information, but also in order to explain how we construct experience (through categorizations and classifications of objects, events, processes, and properties), how we extrapolate from empirical evidence to generalize about observable phenomena, and how we use this evidence to test and confirm hypotheses and theories. (shrink)

In this paper, I analyze some disagreements about scientific ontology as cases of disagreement between epistemic peers. I maintain that the particularities of these cases are better understood if epistemic peerhood is relativized to a perspective-like index of epistemic goals and values. Taking the debate on the metaphysics of laws of nature as a case study, I explore the limits and possibilities of a trans-perspective assessment of positions regarding scientific ontology.

Chakravartty puts forward a view of scientific knowledge that conceives of properties attributed to objects by scientific models as dispositions. Those dispositions refer to the capacity of an object to behave differently in different circumstances. This pluralism of behaviour is intended to show that perspectivalism does not exclude the possibility of non-perspectival knowledge. To support this claim, he offers an analogy between conflicting models and contrastive explanations. I examine the strength of the purported analogy between conflicting models and contrastive explanations. (...) Then, I analyse this dispositionalist account of properties in order to assess whether ontological pluralism can meet the challenge that conflicting models pose to the scientific realism. To conclude, I contend that to accomplish this goal, a more detailed account of dispositional properties should be provided, as well as a theory of explanatory relevance. (shrink)

In August 2014 the Universities of Pretoria and Johannesburg hosted a major international conference in Cape Town, ‘New Thinking about Scientific Realism’, to assess extant discussions of the view in hopes of opening up new avenues of research, and to sow the seeds of further development and consideration of these prospective lines of inquiry. In this, the concluding essay of the Special Issue collecting some of the descendants of these earlier presentations, I extract some of the more striking themes to (...) emerge with the aim of reflecting on their novelty and their promise for the future study of scientific realism. (shrink)

During the past two decades, philosophers of biology have increasingly turned their attention to mechanisms of biological phenomena. Through analyses of mechanistic proposals advanced by biologists, the goal of these philosophers is to understand what a mechanism is and how mechanisms explain. These analyses have generally focused on mechanistic proposals for phenomenon that occur at the cellular or sub-cellular level, such as synapse firing, protein synthesis, or metabolic pathway operation. Little is said about the mechanisms of the macromolecular reactions that (...) underpin these phenomena. These reactions comprise a diverse family of reaction types, and include protein folding, macromolecular complex formation, receptor-ligand interactions, and enzyme catalysis. In this paper, I develop an account of mechanism that focuses exclusively on macromolecular reactions. I begin by reviewing how mechanism is understood in enzymology, and how mechanistic concepts of enzymology apply to macromolecular reactions in general. We will see that the mechanism of a macromolecular reaction is most accurately described as a progression of reaction intermediates, where the evolution of intermediates, from one to the next, is characterized by an energetic coupling between chemistry and protein dynamics. I then make the case that this description necessitates a grounding in a process ontology. To describe the mechanism by which a macromolecular reaction occurs is to describe a process. (shrink)

Existing proposals concerning the ontology of quantum mechanics either involve speculation that goes beyond the scientific evidence or abandon realism about large parts of QM. This paper proposes a way out of this dilemma, by showing that QM as it is formulated in standard textbooks allows for a much more substantive ontological commitment than is usually acknowledged. For this purpose, I defend a non-fundamentalist approach to ontology, which is then applied to various aspects of QM. In particular, I will defend (...) realism about spin, which has been viewed as a particularly hard case for the ontology of QM. (shrink)

According to Gamper, one function of science is to determine how the world is. Science, Gamper continues, rests on a set of basic assumptions, and the gap between basic assumptions and science should be filled by ontological frameworks that accommodates the modal properties of such assumptions. Different frameworks may surely suggest different modal properties. Thus, in so far as we use different basic assumptions, we can have different ontologies with different modal properties. Ontologies affect, in turn, science, which, however, has (...) the power to falsify the ontological frameworks. The aim of this article is to show a possible trouble of Gamper's proposal, here considered as applied to the geographical debate. (shrink)

We examine arguments for distinguishing between ontological and epistemological concepts of fundamentality, focusing in particular on the role that scale plays in these concepts. Using the fractional quantum Hall effect as a case study, we show that we can draw a distinction between ontologically fundamental and non-fundamental theories without insisting that it is only the fundamental theories that get the ontology right: there are cases where non-fundamental theories involve distinct ontologies that better characterize real systems than fundamental ones do. In (...) order to reconcile these distinct ontologies between fundamental and non-fundamental theories, we suggest that ontology must be understood as scale-dependent. (shrink)

This paper considers how to best relate the competing accounts of scientific knowledge that Russell and Reichenbach proposed in the 1930s and 1940s. At the heart of their disagreements are two different accounts of how to best combine a theory of knowledge with scientific realism. Reichenbach argued that a broadly empiricist epistemology should be based on decisions. These decisions or “posits” informed Reichenbach’s defense of induction and a corresponding conception of what knowledge required. Russell maintained that a scientific realist must (...) abandon empiricism in favor of knowledge of some non-demonstrative principles with a non-empirical basis. After identifying the best versions of realism offered by Reichenbach and Russell, the paper concludes with a brief discussion of the limitations of these two approaches. (shrink)