Ever since Hilary Putnam claimed that a realist philosophy is “the only philosophy that doesn’t make the success of science a miracle,” explanations for the success of science have proliferated in the philosophical literature (Putnam 1975, p. 73). Realists argue that the success of science, as exhibited by our ability to accurately predict and explain a wide range of phenomena, indicates that our theories have identified some of the underlying causal structures of the world (e.g., Boyd 1985, Ellis 1985, McMullin (...) 1984, Salmon 1984). Nonrealists counter that success cannot provide a warrant for belief in the truth of scientific theories because there have been successful theories in the past that are now believed to be false (Laudan 1981b). Instead, they offer a naturalized account whereby our theories are designed to be successful predictors and only those which fulfill this goal survive (Laudan 1987, van Fraassen, 1980). (shrink)

The paper discusses the version of entity realism presented by Ian Hacking in his book, Representing and Intervening. Hacking holds that an ontological form of scientific realism, entity realism, may be defended on the basis of experimental practices which involve the manipulation of unobservable entities. There is much to be said in favour of the entity realist position that Hacking defends, especially the pragmatist orientation of his approach to realism. But there are problems with the position. The paper explores two (...) issues that reflect negatively on Hacking’s version of the entity realist position. The first issue relates to the role of description in fixing the reference of theoretical terms. The second issue relates to Hacking’s claim that the argument for entity realism based on experiment is a different kind of argument from the standard argument for scientific realism based on the success of science. (shrink)

A theory’s fertility is one of the standard theoretical virtues. But how is it to be construed? In current philosophical discourse, particularly in the realism debate, theoretical fertility is usually understood in terms of novel success: a theory is fertile if it manages to make successful novel predictions. Another, more permissible, notion of fertility can be found in the work of Ernan McMullin. This kind of fertility, McMullin claims, gives us just as strong grounds for realism. My paper critically assesses (...) McMullin’s notion of fertility and its realist rationale. It concludes that McMullin’s preferred example, namely the fertile development of the Bohr-Sommerfeld model of the atom, does not support McMullin’s argument for realism. Although the implications for the realism debate are as of yet unclear, the case study offers some important methodological lessons. (shrink)

In the on-going debate between scientific realism and its various opponents, a crucial role in challenging the realist claim that success of scientific theories must be attributed to their approximate truth is played by the so-called pessimistic meta-induction: Arguing that the history of science boils down to a succession of theories which, though successful at a time, were eventually discarded only to be replaced by alternative theories which in turn met with the same fate, it purports to show that the (...) empirical success of scientific theories cannot have any bearing on claims about their truth-likeness. Yet, the same historical record suggests a possible strategy to counter this argument. Far from being a barren wasteland, it contains cases which point to the need of adopting a selective attitude when passing judgments about truth-likeness of theories. In this vein, Psillos has proposed the so-called divide et impera move. It consists in pointing out that responsibility for the success of a theory should be attributed to an indispensable core element in it, acting in unison with other elements reflecting the concrete historical conditions under which the theory was formulated. In what follows it is argued that the discovery of Kepler's first two laws and the transition to Newtonian mechanics provides a notable case to exhibit the divide et impera move. All the more so, since—as will be shown—Kepler himself employs a variant of this move, a fact that sheds light on the philosophical implications of his theories. As a result, it will be argued that the appropriate selective attitude towards theories becomes solidly warranted if wedded to the diachronic element in the process of a theory's development. (shrink)

The epistemic conception of scientific progress equates progress with accumulation of scientific knowledge. I argue that the epistemic conception fails to fully capture scientific progress: theoretical progress, in particular, can transcend scientific knowledge in important ways. Sometimes theoretical progress can be a matter of new theories ‘latching better onto unobservable reality’ in a way that need not be a matter of new knowledge. Recognising this further dimension of theoretical progress is particularly significant for understanding scientific realism, since realism is naturally (...) construed as the claim that science makes theoretical progress. Some prominent realist positions are best understood in terms of commitment to theoretical progress that cannot be equated with accumulation of scientific knowledge. (shrink)

The epistemic conception of scientific progress equates progress with accumulation of scientific knowledge. I argue that the epistemic conception fails to fully capture scientific progress: theoretical progress, in particular, can transcend scientific knowledge in important ways. Sometimes theoretical progress can be a matter of new theories ‘latching better onto unobservable reality’ in a way that need not be a matter of new knowledge. Recognising this further dimension of theoretical progress is particularly significant for understanding scientific realism, since realism is naturally (...) construed as the claim that science makes theoretical progress. Some prominent realist positions are best understood in terms of commitment to theoretical progress that cannot be equated with accumulation of scientific knowledge. (shrink)

This paper takes another look at a case study which has featured prominently in a variety of arguments for rival realist positions. After critically reviewing the previous commentaries of the theory shift that took place in the transition from Fresnel’s ether to Maxwell’s electromagnetic theory of optics, it will defend a slightly different reading of this historical case study. Central to this task is the notion of explanatory approximate truth, a concept which must be carefully analysed to begin with. With (...) this notion properly understood, it will be finally argued, the popular Fresnel-Maxwell case study points towards a novel formulation of scientific realism. (shrink)

The Pessimistic Induction from falsity of past theories forms a perennial argument against scientific realism. This paper considers and rebuts two recent arguments—due to Lewis (2001) and Lange (2002)—to the conclusion that the Pessimistic Induction (in its best known form) is fallacious. It re-establishes the dignity of the Pessimistic Induction by calling to mind the basic objective of the argument, and hence restores the propriety of the realist program of responding to PMI by undermining one or another of its premises.

I erect a framework within the semantic view of theories for explaining the empirical success of internally inconsistent models and theories, with scientific realism in mind. The framework is an instance of the ‘content-driven’ approach to inconsistency, advocated by both Norton (Philos Sci 54:327–350, 1987) and Smith (Stud Hist Philos Sci 19:429–445, 1988a, In: Fine A, Leplin J (eds) PSA1988, 1988b), whose ideas my analysis aims to clarify and substantiate.

I review prominent historical arguments against scientific realism to indicate how they display a systematic overshooting in the conclusions drawn from the historical evidence. The root of the overshooting can be located in some critical, undue presuppositions regarding realism. I will highlight these presuppositions in connection with both Laudan’s ‘Old induction’ and Stanford’s New induction, and then delineate a minimal realist view that does without the problematic presuppositions.

Semantic realism can be characterised as the idea that scientific theories are truth-bearers, and that they are true or false in virtue of the world. This notion is often assumed, but rarely discussed in the literature. I examine how it fares in the context of the semantic view of theories and in connection with the literature on scientific representation. Making sense of semantic realism requires specifying the conditions of application of theoretical models, even for models that are not actually used, (...) which leads to several difficulties. My conclusion is that semantic realism is far more demanding than one would expect. Finally, I briefly examine some pragmatist alternatives. (shrink)

Le réalisme structural est une tentative d’établir un compromis entre le réalisme scientifique et l’empirisme, en restreignant le réalisme à la structure relationnelle des théories scientifiques. Il se décline en deux versions, épistémique et ontique. Le réalisme structural ontique propose de concevoir les relations nomologiques décrites par les théories comme des éléments primitifs de la réalité. Il est motivé, notamment, par le fait que sous sa forme épistémique, le réalisme structural ne se distingue pas réellement d’une position empiriste. Cependant, il (...) fait face à des difficultés, en particulier pour différencier relations physiques et mathématiques et rendre compte de l’ancrage expérimental des théories. Il est possible d’établir un parallèle entre ces difficultés et le problème de la mesure en mécanique quantique, qui concerne lui aussi les rapports entre modèle théorique et expérience : on constate alors qu’un réalisme structural épistémique est plus à même d’y répondre. Une solution de compromis entre le réalisme structural ontique et le réalisme structural épistémique pourrait permettre de conserver les avantages des deux positions. -/- Structural realism attempts to make a compromise between scientific realism and empiricism, by restricting our realist commitment to the relational structure of scientific theories. There are two main versions of the position: ontic, or epistemic. According to ontic structural realism, the nomological relations expressed by theories are the primitive entities of reality. This ontic version is motivated in particular by arguments to the effect that epistemic versions are not really distinct from mere empiricism. However according to some authors, it’s not clear that ontic structural realism can differentiate between physical and mathematical relations, and account for the relations between scientific theories and their experimental basis. These difficulties can be related to the measurement problem in quantum mechanics, which also concerns the link between theoretical models and experiments. It appears that epistemic structural realism is in a better position to respond to these difficulties. A compromise between both versions of structural realism could allow us to keep the advantages of both. (shrink)

Naturalised realism’ is presented as a version of realism which is more compatible with the history of science than convergent or explanationist forms of realism. The account is unpacked according to four theses: 1) Whether realism is warranted with regards to a particular theory depends on the kind and quality of evidence available for that theory; 2) Reference is about causal interaction with the world; 3) Most of science happens somewhere in between instrumentalism and scientific realism on a continuum of (...) stances towards the status of theories; 4) The degree to which realism is warranted has something to do with the degree to which theories successfully refer, rather than with the truth of theories. (shrink)

In this article, against the background of a notion of ‘assembled’ truth, the evolutionary progressiveness of a theory is suggested as novel and promising explanation for the success of science. A new version of realism in science, referred to as ‘naturalised realism’ is outlined. Naturalised realism is ‘fallibilist’ in the unique sense that it captures and mimics the self-corrective core of scientific knowledge and its progress. It is argued that naturalised realism disarms Kyle Stanford’s anti-realist ‘new induction’ threats by showing (...) that ‘explanationism’ and his ‘epistemic instrumentalism’ are just two positions among many on a constantly evolving continuum of options between instrumentalism and full-blown realism. In particular it is demonstrated that not only can naturalised realism redefine the terms of realist debate in such a way that no talk of miracles need enter the debate, but it also promises interesting defenses against inductive- and under-determination-based anti-realist arguments. (shrink)

The global pessimistic meta-induction argues from the falsity of scientific theories accepted in the past to the likely falsity of currently accepted scientific theories. I contend that this argument commits a statistical error previously unmentioned in the literature and is self-undermining. I then compare the global pessimistic meta-induction to a local pessimistic meta-induction based on recent negative assessments of the reliability of medical research. If there is any future in drawing pessimistic conclusions from the history of science, it lies in (...) local meta-inductions, but these meta-inductions will not result in global distrust of the results of science. (shrink)

First, I answer the controversial question ’What is scientific realism?’ with extensive reference to the varied accounts of the position in the literature. Second, I provide an overview of the key developments in the debate concerning scientific realism over the past decade. Third, I provide a summary of the other contributions to this special issue.

Stanford’s argument against scientific realism focuses on theories, just as many earlier arguments from inconceivability have. However, there are possible arguments against scientific realism involving unconceived (or inconceivable) entities of different types: observations, models, predictions, explanations, methods, instruments, experiments, and values. This paper charts such arguments. In combination, they present the strongest challenge yet to scientific realism.

First, I identify a methodological thesis associated with scientific realism. This has different variants, but each concerns the reliability of scientific methods in connection with acquiring, or approaching, truth or approximate truth. Second, I show how this thesis bears on what scientists should do when considering new theories that significantly contradict older theories. Third, I explore how vulnerable scientific realism is to a reductio ad absurdum as a result. Finally, I consider which variants of the methodological thesis are the most (...) defensible in light of the earlier findings. (shrink)

This survey of major developments in North American philosophy of science begins with the mid-1960s consolidation of the disciplinary synthesis of internalist history and philosophy of science (HPS) as a response to criticisms of logical empiricism. These developments are grouped for discussion under the following headings: historical metamethodologies, scientific realisms, philosophies of the special sciences, revivals of empiricism, cognitivist naturalisms, social epistemologies, feminist theories of science, studies of experiment and the disunity of science, and studies of science as practice and (...) culture. A unifying theme of the survey is the relation between historical metamethodologists and scientific realists, which dominated philosophical work in the late 1970s. I argue that many of the alternative cognitive naturalisms, social epistemologies, and feminist theories that have been proposed can be understood as analogues to the differences between metamethodological theories of scientific rationality and realist accounts of successful reference to real causal processes. Recent work on experiment, scientific practice, and the culture of science may, however, challenge the underlying conception of the field according to which realism and historical rationalism (or their descendants) are the important alternatives available, and thus may take philosophy of science in new directions. (shrink)

There is a long-standing debate in the philosophy of action and the philosophy of science over folk psychological explanations of human action: do the (perhaps implicit) generalizations that underwrite such explanations purport to state contingent, empirically established connections between beliefs, desires, and actions, or do such generalizations serve rather to define, at least in part, what it is to have a belief or desire, or perform an action? This question has proven important because of certain traditional assumptions made about the (...) role of law-statements in scientific explanations. According to this tradition, law-statements take the form of generalizations, and the laws we find in well-established sciences are contingent and empirical; as such, if the kinds of generalizations at work in folk psychological explanations of human action act like definitions, or state conceptual connections, then such generalizations could not play the kind of explanatory role we find in mature sciences. This paper argues that the aforementioned way of framing the debate reflects a still powerful but impoverished conception of the role laws play in scientific explanations, a conception that, moreover, cannot be reconciled with a good deal of actual scientific practice. When we update the philosophy of science, we find the concerns that are raised for folk psychological explanations largely evaporate or are found not to be specific to such explanations. (shrink)

This review of recent work in the philosophy of science motivated by a commitment to 'naturalism' begins by identifying three key axioms and one theorem shared by philosophers thus self-styled. Owing much to Quine and Ernest Nagel, these philosophers of science share a common agenda with naturalists elsewhere in philosophy. But they have disagreed among themselves about how the axioms and the theorems they share settle long-standing disputes in the philosophy of science. After expounding these disagreements in the work of (...) Boyd, Giere, Laudan, and Kitcher, I argue that naturalism needs to look for more than mere consistency in its foundations. (shrink)

Philip Kitcher's account of scientific progress incorporates a conception of explanatory unification that invites the so-called 'obsessive unifier' worry, to wit, that in our drive to unify the phenomena we might impose artificial structure on the world and consequently produce an incorrect view of how things, in fact, are. I argue that Kitcher's attempt to address this worry is unsatisfactory because it relies on an ability to choose between rival patterns of explanation which itself rests on the relevant choice having (...) already been made. I also suggest a way of answering the worry that Kitcher is not likely to endorse. (shrink)

In this paper, I argue that if one is already an advocate of scientific realism, then one would be also a realist about laws of nature. To show this, I argue that only scientific realists would accept that non-accidental regularities require explanation and that their genuine explanation is given by laws of nature. Then, from this conclusion, it seems that scientific realists have reason to believe that there are laws of nature in an objective sense. If this is correct, the (...) conclusion is that there are no reasons for advocates of scientific realism to be skeptics about laws of nature. (shrink)

It is demonstrated that the reduction of a physical theory S to another one, T, in the sense that S can be derived from T holds in general only for the mathematical framework. The interpretation of S and the associated central terms cannot all be derived from those of T because of the qualitative differences between the cognitive levels of S and T. Their cognitively autonomous status leads to an epistemic as well as an ontological pluralism. This pluralism is consistent (...) with the unity of nature in the sense of a substantive monism. (shrink)

Building on previous work, I continue the arguments for scientific realism in the presence of a natural level structure of science. That structure results from a cognitive antireductionism that calls for the retention of mature theories even though they have been "superseded". The level structure is based on "scientific truth" characterized by a theory's validity domain and the confirming empirical data. Reductionism (including fundamentalism) fails cognitively because of qualitative differences in the ontology and semantics of successive theories. This cognitive failure (...) exists in spite of the mathematical success of theory reduction. The claim for scientific realism is strongly based on theory coherence between theories on adjacent levels. Level coherence consists of mathematical relations between levels, as well as of reductive explanations. The latter refers to questions that can be posed (but not answered) on a superseded level, but which can be answered (explained) on the superseding level. In view of the pluralism generated by cognitive antireductionism, theory coherence is claimed to be so compelling that it provides strong epistemic justification for a pluralistic scientific realism. (shrink)

Criteria are given to characterize mature theories in contradistinction to developing theories. We lean heavily on the physical sciences. An established theory is defined as a mature one with known validity limits. The approximate truth of such theories is thereby given a quantitative character. Superseding theories do not falsify established theories because the latter are protected by their validity limits. This view of scientific realism leads to ontological levels and cumulativity of knowledge. It is applied to a defense of realism (...) against recent attacks by Laudan. (shrink)

We present a model of the distribution of labour in science. Such models tend to rely on the mechanism of the invisible hand . Our analysis starts from the necessity of standards in distributed processes and the possibility of multiple standards in science. Invisible hand models turn out to have only limited scope because they are restricted to describing the atypical single-standard case. Our model is a generalisation of these models to J standards; single-standard models such as Kitcher are a (...) limiting case. We introduce and formalise this model, demonstrate its dynamics and conclude that the conclusions commonly derived from invisible hand models about the distribution of labour in science are not robust against changes in the number of standards. (shrink)

Williams and J. Fraser have recently argued that effective field theory methods enable scientific realists to make more reliable ontological commitments in quantum field theory than those commonly made. In this paper, I show that the interpretative relevance of these methods extends beyond the specific context of QFT by identifying common structural features shared by effective theories across physics. In particular, I argue that effective theories are best characterized by the fact that they contain intrinsic empirical limitations, and I extract (...) from their structure one central interpretative constraint for making more reliable ontological commitments in different subfields of physics. While this is in principle good news, this constraint still raises a challenge for scientific realists in some contexts, and I bring the point home by focusing on Williams’s and J. Fraser’s defense of selective realism in QFT. (shrink)

Catherine Elgin has recently argued that a nonfactive conception of understanding is required to accommodate the epistemic successes of science that make essential use of idealizations and models. In this paper, I argue that the fact that our best scientific models and theories are pervasively inaccurate representations can be made compatible with a more nuanced form of scientific realism that I call Understanding Realism. According to this view, science aims at (and often achieves) factive scientific understanding of natural phenomena. I (...) contend that this factive scientific understanding is provided by grasping a set of true modal information about the phenomenon of interest. Furthermore, contrary to Elgin’s view, I argue that the facticity of this kind of scientific understanding can be separated from the inaccuracy of the models and theories used to produce it. (shrink)

This article investigates the implications of string theory for the conception of scientific theory confirmation. The classical understanding of theory confirmation is based on the assumption that scientific theory building is underdetermined by the available empirical data. Several arguments are presented, which suggest a devaluation of this ‘principle of scientific underdetermination’ in the context of string theory. An altered conception of scientific progress emerges that is not based on the notion of theory succession.

InScience and Values (1984) and other, more recent, works, e.g. (1987a, 1987b, 1989a, 1989b, 1990), Larry Laudan proposes a theory of scientific debate he dubs the reticulated model of scientific rationality (Laudan, 1984, pp. 50–66). The model stands in sharp contrast to hierarchical approaches to rationality exemplified by Popper (1959), Hempel (1965), and Reichenbach (1938), as well as the conventionalist views of rationality defended by Carnap (1950), Popper (1959), Kuhn (1962), and Lakatos (1978). Ironically, the model commits some of the (...) same errors Laudan finds in hierarchicalist and conventionalists approaches to scientific rationality. This paper will show that the model can be fixed by recognizing that criteria of goal assessment have no privileged status. These rules are best viewed as simply rules of rationality (or rules of scientific method) by another name. (shrink)

Traditional debates about scientific realism tend to focus on issues concerning scientific representation and de-emphasize issues concerning scientific intervention. Questions about the relation between theories and the world, the nature of scientific inference, and the structure of scientific explanations have occupied a central place in the realism debate, while questions about experimentation and technology have not. Ian Hacking's experimental realism attempts to reverse this trend by shifting the defense of realism away from representation to intervention. Experimental realism, according to Hacking, (...) does not require us to believe that our theories are true, nor does its defense depend on inference to the best explanation. For Hacking, the strongest proof for realism is that we can manipulate objects: 'So far as I'm concerned, if you can spray them, then they are real'. (shrink)

Scientists have rules pertaining to data fabrication and falsification that are enforced with significant punishments, such as loss of funding, termination of employment, or imprisonment. These rules pertain to data that describe observable and unobservable entities. In this commentary I argue that scientists would not adopt rules that impose harsh penalties on researchers for data fabrication or falsification unless they believed that an aim of scientific research is to develop true theories and hypotheses about entities that exist, including unobservable ones. (...) This argument presents a challenge for constructive empiricists, such as van Fraassen. Constructive empiricists need to be able to explain why rules pertaining to data fabrication and falsification do not threaten their philosophy of science. (shrink)

In this rather technical paper we establish a useful combination of belief revision and verisimilitude according to which better theories provide better predictions, and revising with more verisimilar data results in theories that are closer to the truth. Moreover, this paper presents two alternative definitions of refined verisimilitude, which are more perspicuous than the algebraic version used in previous publications.

As Laudan and Fine show, and Boyd concedes, the attempt to infer the truth of scientific realism from the fact that it putatively provides the best explanation of the instrumental success of science is circular, since what is to be shown is precisely the legitimacy of such abductive inferences. Hacking's "experimental argument for scientific realism about entities" is one of the few arguments for scientific realism that purports to avoid this circularity. We argue that Hacking's argument is as dependent on (...) inference to the best explanation (IBE), and therefore as weak, as the other realist arguments. (shrink)

Hume famously warned us that the ‘[The] ultimate springs and principles are totally shut up from human curiosity and enquiry’. Or, again, Newton: ‘Hitherto I have not been able to discover the cause of these properties of gravity … and I frame no hypotheses.’ Aristotelian science was concerned with just such questions, the specification of occult qualities, the real essences that answer the question What is matter, etc?, the preoccupation with circular definitions such as dormative virtues, and so on. The (...) rise of modern science is usually seen as a break with the sterility of Aristotelianism, so what exactly is it that modern science does discover, if it is not the essential nature of matter, of force, of energy, of space and time? A famous answer was provided by Poincaré: ‘The true relations between these real objects are the only reality we can attain.’ This is often regarded as the manifesto of so-called structural realism, as espoused in recent years by John Worrall, for example ). In response to the arguments of Larry Laudan against convergent realism, Worrall points to the continuity in the formal relations between elements of reality expressed by mathematical equations, while the intrinsic nature of these elements of reality gets constantly revised. (shrink)

Several philosophers of science have claimed that the correspondence principle can be generalized from quantum physics to all of (particularly physical) science and that in fact it constitutes one of the major heuristical rules for the construction of new theories. In order to evaluate these claims, first the use of the correspondence principle in (the genesis of) quantum mechanics will be examined in detail. It is concluded from this and from other examples in the history of science that the principle (...) should be qualified with respect to its nature and relativized with respect to its scope of application. At the same time this conclusion implies a qualification and a relativization of the heuristic power of the principle. Generally speaking, intertheoretical correspondence is primarily of a formal-mathematical and empirical but not of a conceptual nature. Moreover, it only applies to certain parts of the theories involved. Finally, a number of philosophical justifications of the principle are discussed and some conclusions are drawn concerning the debates on theory reduction and on the discovery-justification distinction. (shrink)

An argument, different from the Newman objection, against the view that the cognitive content of a theory is exhausted by its Ramsey sentence is reviewed. The crux of the argument is that Ramsification may ruin inductive systematization between theory and observation. The argument also has some implications concerning the issue of underdetermination.

Philosophy of Science, Volume 63, Issue Supplement. Proceedings of the 1996 Biennial Meetings of the Philosophy of Science Association. Part I: Contributed Papers (Sep.

Over the last two decades, the debate over scientific realism has been dominated by two arguments that pull in contrary directions: the 'no miracle' argument and the 'pessimistic induction'. The latter suggests that the historical record destroys the realist's belief in an explanatory connection between truthlikeness and genuine empirical success. This paper analyzes the structure of the 'pessimistic induction', presents a move--the divide et impera move--that neutralizes it, and motivates a substantive yet realistic version of scientific realism. This move is (...) also compared with Worrall's and Kitcher's recent reactions to the 'pessimistic induction'. (shrink)

I began this study with Laudan's argument from the pessimistic induction and I promised to show that the caloric theory of heat cannot be used to support the premisses of the meta-induction on past scientific theories. I tried to show that the laws of experimental calorimetry, adiabatic change and Carnot's theory of the motive power of heat were independent of the assumption that heat is a material substance, approximately true, deducible and accounted for within thermodynamics.I stressed that results and were (...) known to most theorists of the caloric theory and that result was put forward by the founders of the new thermodynamics. In other words, the truth-content of the caloric theory was located, selected carefully, and preserved by the founders of thermodynamics.However, the reader might think that even if I have succeeded in showing that laudan is wrong about the caloric theory, I have not shown how the strategy followed in this paper can be generalised against the pessimistic meta-induction. I think that the general strategy against Laudan's argument suggested in this paper is this: the empirical success of a mature scientific theory suggests that there are respects and degrees in which this theory is true. The difficulty for — and and real challenge to — philosophers of science is to suggest ways in which this truth-content can be located and shown to be preserved — if at all — to subsequent theories. In particular, the empirical success of a theory does not, automatically, suggest that all theoretical terms of the theory refer. On the contrary, judgments of referential success depend on which theoretical claims are well-supported by the evidence. This is a matter of specific investigation. Generally, one would expect that claims about theoretical entities which are not strongly supported by the evidence or turn out to be independent of the evidence at hand, are not compelling. For simply, if the evidence does not make it likely that our beliefs about putative theoretical entities are approximately correct, a belief in those entities would be ill-founded and unjustified. Theoretical extrapolations in science are indespensable, but they are not arbitrary. If the evidence does not warrant them I do not see why someone should commit herself to them. In a sense, the problem with empricist philisophers is not that they demand that theoretical beliefs must be warranted by evidence. Rather, it is that they claim that no evidence can warrant theorretical beliefs. A realist philosopher of science would not disagree on the first, but she has good grounds to deny the second.I argued that claims about theoretical entities which are not strongly supported by the evidence must not be taken as belief-worthy. But can one sustaon the more ambitious view that loosely supported parts of a theory tend to be just those that include non-referring terms? There is an obvious excess risk in such a generalisation. For there are well-known cases in which a theoretical claim was initially weakly supported by the evidence. (shrink)