Underdetermination,realism and empirical equivalence

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.     

Why Evolution is Really Indeterministic

Leslie Graves, Barbara Horan and Alex Rosenberg (1999) have argued that the process of evolution is really deterministic, so we should be instrumentalists about our probabilistic evolutionary theory. I criticize the consistency of their view. I argue that because they are realists towards multiple theories (quantum mechanics and macrophysics) their arguments against realism for another scientific theory fail. The main point of this paper is critical, but in order to set up this criticism I explore the ramifications of realism for multiple theories. Finally, I offer a brief metaphysical justification for realism about multiple theories. This view justifies realism for evolutionary theory, which has been defended by Robert Brandon and Scott Carson (1996).     

Explaining the Success of Science: Kuhn and Scientific Realists

In this essay, I critically evaluate the approaches to explaining the success of science in Kuhn and the works of inference-to-the-best-explanation scientific realists. Kuhn’s challenge to realists, who invoke the truth of theories to explain their success, is two-fold. His paradigm-account of success confronts realists with the problem of theory change, and the historical fact of successful theories later rejected as false. Secondly, Kuhn’s account of the success of science has no need to bring truth into the explanation. In turn, I argue that weakness in Kuhn and the prevailing forms of scientific realism motivate a better account of realism which I characterize as ‘best current theory realism’ and defend against the pessimistic meta-induction and the problem of theory-change. This realism argues that the best explanation of the success of current and past scientific theories only requires the simple claim that our best current theories are true. Kuhn’s account can explain how normal science succeeds but cannot account for why its problem solutions work where they do and why they fail for other puzzles.     

The Miraculous Choice Argument for Realism

The miracle argument for scientific realism can be cast in two forms: according to the miraculous theory argument, realism is the only position which does not make the empirical successes of particular theories miraculous. According to the miraculous choice argument, realism is the only position which does not render the fact that empirically successful theories have been chosen a miracle. A vast literature discusses the miraculous theory argument, but the miraculous choice argument has been unjustifiably neglected. I raise two objections to Richard Boyd's defense of the latter: (1) we have no miracle free account of the emergence of take-off theories and (2) the anti-realist can account for the non-miraculous choice of empirically successful theories by attributing mere empirical adequacy to background theory. I argue that the availability of extra-empirical criteria that are arguably truth conductive but not theory-laden suffices to answer (1), and the unavailability of extra-empirical criteria that are conductive to empirical adequacy but not necessarily to truth (and are also not theory-laden) constitutes to reply to (2). The prospects for a realist victory are at least somewhat promising, on a controversial assumption about the rate at which empirically successful theories emerge.     

Non‐competitor Conditions in the Scientific Realism Debate

A general insight of 20th‐century philosophy of science is that the acceptance of a scientific theory is grounded, not merely on a theory’s relation to data, but on its status as having no, or being superior to its, competitors. I explore the ways in which scientific realists might be thought to utilise this insight, have in fact utilised it, and can legitimately utilise it. In more detail, I point out that, barring a natural but mistaken characterisation of scientific realism, traditional realism has not utilised that insight regarding scientific theories, i.e., has not explicitly factored that insight into, and invoked it as justification for, what realists believe. Nonetheless, a new form of realism has. In response to a key historical threat, two of the most thoroughly developed contemporary versions of realism—one put forward by Jarrett Leplin, another by Stathis Psillos—are anchored on the sensible tactic of requiring that the theories to which realists commit themselves have no competitors. I argue, however, that the particular kind of non‐competitor condition they invoke is illegitimate in the context of the realism debate. I contend further that invoking a non‐competitor condition that is legitimate, sensible, and even, as it turns out, required in the context of the debate threatens to eliminate the possibility of scientific realism altogether.     

Realism Despite Cognitive Antireductionism

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.     

The Argument from Underconsideration and Relative Realism

In this article, through a critical examination of K. Brad Wray's version of the argument from underconsideration against scientific realism, I articulate a modest version of scientific realism. This modest realist position, which I call ‘relative realism’, preserves the scientific realist's optimism about science's ability to get closer to the truth while, at the same time, taking on board the antirealist's premise that theory evaluation is comparative, and thus that there are no good reasons to think that science's best theories are close to the truth.     

Euthyphro and Moral Realism: A Reply to Harrison

Gerald Harrison identifies two Euthyphro-related concerns for divine command theories and makes the case that to the extent that these concerns make trouble for divine command theories they also make trouble for non-naturalistic moral realism and naturalistic moral realism (call this the parity thesis). He also offers responses to the two concerns on behalf of divine command theorists. I show here that the parity thesis does not hold for the most commonly discussed version of divine command theory. I further argue that his responses to the two concerns fail. Finally, I draw on some of Harrison’s ideas to identify an advantage that non-naturalistic moral realism has over divine command theories and naturalistic moral realism.     

Scientific realism and the criteria for theory-choice

The central terms of certain theories which were valued highly in the past, such as the phlogiston theory, are now believed by realists not to refer. Laudan and others have claimed that, in the light of the existence of such theories, scientific realism is untenable. This paper argues in response that realism is consistent with — and indeed is able to explain — such theories' having been highly valued and yet not being close to the truth. It follows that the set of highly-valued past theories cited by Laudan, presumed to militate against realism, is in fact innocuous to the doctrine. The argument hinges largely on identifying the grounds on which theory-adoption is actually performed.     

Depressive cognition: a test of depressive realism versus negativity using general knowledge questions

This research is an examination of whether cognition in depressed individuals incorporates a realistic view of the world or a general tendency toward negativity. Participants provided two types of probability judgments of the likelihood that they correctly answered general knowledge questions: the probability that they correctly answered each of the individual questions and an aggregate judgment, after completing the questionnaire, of the percentage of all the questions they thought they had correctly answered. These tasks generally elicit overconfidence and accuracy in nondepressives. In accord with theories of both depressive realism and general negativity, in their item-by-item assessments of their answers to the individual questions, depressed participants demonstrated less overconfidence than nondepressed participants. In accord with the theory of general negativity but not with the theory of depressive realism, however, depressed participants demonstrated underconfidence in their aggregate judgments. The implications of these findings on theories of depressive cognition are discussed.     

Depressive Cognition: A Test of Depressive Realism Versus Negativity Using General Knowledge Questions

This research is an examination of whether cognition in depressed individuals incorporates a realistic view of the world or a general tendency toward negativity. Participants provided two types of probability judgments of the likelihood that they correctly answered general knowledge questions: the probability that they correctly answered each of the individual questions and an aggregate judgment, after completing the questionnaire, of the percentage of all the questions they thought they had correctly answered. These tasks generally elicit overconfidence and accuracy in nondepressives. In accord with theories of both depressive realism and general negativity, in their item-by-item assessments of their answers to the individual questions, depressed participants demonstrated less overconfidence than nondepressed participants. In accord with the theory of general negativity but not with the theory of depressive realism, however, depressed participants demonstrated underconfidence in their aggregate judgments. The implications of these findings on theories of depressive cognition are discussed.     

Scientific Realism in Action: Molecular Models and Boltzmann’s Bildtheorie

This paper approaches the scientific realism question from a naturalistic perspective. On the basis of a historical case study of the work of James Clerk Maxwell and Ludwig Boltzmann on the kinetic theory of gases, it shows that scientists’ views about the epistemological status of theories and models typically interact with their scientific results. Subsequently, the implications of this result for the current realism debate are analysed. The case study supports Giere’s moderately realist view of scientific models and theories, based on the notion of similarity, and it highlights the crucial role of model users. The paper concludes with a discussion of Boltzmann’s Bildtheorie, the sophisticated form of realism that he developed in response to the scientific problems of kinetic theory.     

The Value of Perception

This paper develops a form of transcendental naïve realism. According to naïve realism, veridical perceptual experiences are essentially relational. According to transcendental naïve realism, the naïve realist theory of perception is not just one theory of perception amongst others, to be established as an inference to the best explanation and assessed on the basis of a cost-benefit analysis that weighs performance along a number of different dimensions: for instance, fidelity to appearances, simplicity, systematicity, fit with scientific theories, and so on. Rather, naïve realism enjoys a special status in debates in the philosophy of perception because it represents part of the transcendental project of explaining how it is possible that perceptual experience has the distinctive characteristics it does. One of the potentially most interesting prospects of adopting a transcendental attitude towards naïve realism is that it promises to make the naïve realist theory of perception, in some sense, immune to falsification. This paper develops a modest form of transcendental naïve realism modelled loosely on the account of the reactive attitudes provided by Strawson in ‘Freedom and Resentment’, and suggests one way of understanding the claim that naïve realism is immune to falsification.     

Underdetermination and Meaning Indeterminacy: What is the Difference?

The first part of this paper discusses Quine’s views on underdetermination of theory by evidence, and the indeterminacy of translation, or meaning, in relation to certain physical theories. The underdetermination thesis says different theories can be supported by the same evidence, and the indeterminacy thesis says the same component of a theory that is underdetermined by evidence is also meaning indeterminate. A few examples of underdetermination and meaning indeterminacy are given in the text. In the second part of the paper, Quine’s scientific realism is discussed briefly, along with some of the difficulties encountered when considering the ‘truth’ of different empirically equivalent theories. It is concluded that the difference between underdetermination and indeterminacy, while significant, is not as great as Quine claims. It just means that after we have chosen a framework theory, from a number of empirically equivalent ones, we still have further choices along two different dimensions.     

The Model Theoretic Argument, Indirect Realism, and the Causal Theory of Reference Objection

Abstract: Hilary Putnam has reformulated his model-theoretic argument as an argument against indirect realism in the philosophy of perception. This new argument is reviewed and defended. Putnam's new focus on philosophical theories of perception (instead of metaphysical realism) makes better sense of his previous responses to the objection from the causal theory of reference. It is argued that the model-theoretic argument can also be construed as an argument that holders of a causal theory of reference should adopt direct realism in the philosophy of perception.     

Two Models of Moral Judgment

This paper compares two theories and their two corresponding computational models of human moral judgment. In order to better address psychological realism and generality of theories of moral judgment, more detailed and more psychologically nuanced models are needed. In particular, a motivationally based theory of moral judgment (and its corresponding computational model) is developed in this paper that provides a more accurate account of human moral judgment than an existing emotion‐reason conflict theory. Simulations based on the theory capture and explain a range of relevant human data. They account not only for the original data that were used to support the emotion – reason conflict theory, but also for a wider range of data and phenomena.     

Informational Realism and World 3

This paper takes up a suggestion made by Floridi that the digital revolution is bringing about a profound change in our metaphysics. The paper aims to bring some older views from philosophy of mathematics to bear on this problem. The older views are concerned principally with mathematical realism—that is the claim that mathematical entities such as numbers exist. The new context for the discussion is informational realism, where the problem shifts to the question of the reality of information. Mathematical realism is perhaps a special case of informational realism. The older views concerned with mathematical realism are the various theories of World 3. The concept of World 3 was introduced by Frege, whose position was close to Plato’s original views. Popper developed the theory of World 3 in a different direction which is characterised as ‘constructive Platonism’. But how is World 3 constructed? This is explored by means of two analogies: the analogy with money, and the analogy with meaning, as explicated by the later Wittgenstein. This leads to the development of an account of informational realism as constructive Aristoteliansim. Finally, this version of informational realism is compared with the informational structural realism which Floridi develops in his 2008 and 2009 papers in Synthese. Similarities and differences between the two positions are noted.     

The pessimistic induction,the flight to reference and the metaphysical zoo

Scientific realism says of our best scientific theories that (1) most of their important posits exist and (2) most of their central claims are approximately true. Antirealists sometimes offer the pessimistic induction in reply: since (1) and (2) are false about past successful theories, they are probably false about our own best theories too. The contemporary debate about this argument has turned (and become stuck) on the question, Do the central terms of successful scientific theories refer? For example, Larry Laudan offers a list of successful theories that employed central terms that failed to refer, and Philip Kitcher replies with a view about reference in which the central terms of such theories did sometimes refer. This article attempts to break this stalemate by proposing a direct version of the pessimistic induction, one that makes no explicit appeal to a substantive notion or theory of reference. While it is premature to say that this argument succeeds in showing that realism is probably false, the direct pessimistic induction is not subject to any kind of reference-based objection that might cripple a weaker, indirect version of the argument. Any attempt to trounce the direct pessimistic induction with a theory of reference fails.     

PHYSICAL REALISM

Physical realism is the thesis that the world is more or less as present‐day physical theory says it is, i.e. a mind‐independent reality, that consists fundamentally of physical objects that have causal powers, are located in space and time, belong to natural kinds, and interact causally with each other in various natural kinds of ways. It is thus a modern form of physicalism that takes due account of the natural kinds structure of the world. It is a thesis that many present‐day scientific realists would surely accept. Indeed, some might say that physical realism just is scientific realism, but under another name. However, the argument that is presented for physical realism is not the standard one for scientific realism. It is not a two‐stage argument from the success of science to the truth of scientific theories to the reality of the entities postulated in these theories. It is more powerful than this, because it is more direct, and its premisses are more secure. It is more direct, because it develops what is basically a physicalist ontology as the only plausible metaphysical explanation of the new scientific image of the world. It is more secure, in that it does not depend, as the standard argument does, on any doubtful generalisations about the nature or role of scientific theory.