Bas C. van Fraassen

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with links to ABSTRACTS -- if available -- and otherwise directly to articles. Note: Published versions are available here only if at least five years old, due to copyright restrictions. Others are available in final or penultimate draft -- find the published versions by title in the publications lists .

>>>> See below for PREVIOUS (before 2000)<<<<<


Against Naturalized Empiricism

pp. 68-88 in P. Leonardi and M. Santambrogio (eds.) On Quine . Cambridge Univ. Press, 1995.


Can empiricism be developed in such a way as to involve neither the sort of metaphysics to which it was traditionally the reaction, nor foundationalist epistemology? Quine's 'naturalized epistemology' and 'naturalized' versions of empiricism are not adequate to this task; Carnap's "Empiricism, semantics, and ontology" may contain a valuable clue, despite its apparent problems.

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Conditionalization, A New Argument For

Topoi 18 (1999), 93-96.


Probabilism in epistemology does not have to be of the Bayesian variety. The probabilist represents a person's opinion as a probability function; the Bayesian adds that rational change of opinion must take the form of conditionalizing on new evidence. I will argue that this is the correct procedure under certain special conditions. Those special conditions are important, and instantiated for example in scientific experimentation, but hardly universal. My argument will be related to the much maligned Reflection Principle (van Fraassen 1984,1995), and partly inspired by the work of Brian Skyrms (1987).

A Defense of Van Fraassen's Critique of Abductive Inference: Reply to Psillos

James Ladyman, Igor Douven, Leon Horsten and Bas C. van Fraassen

Philosophical Quarterly 47 (1997), 305-321.


Psillos has recently argued that van Fraassen's arguments against abduction fail. Moreover, he claimed that, if successful, these arguments would equally undermine van Fraassen's own constructive empiricism, for, Psillos thinks, it is only by appeal to abduction that constructive empiricism can be saved from issuing in a bald scepticism. In this paper we show that Psillos' criticisms are misguided, and that they are mostly based on grave misinterpretations of van Fraassen's arguments. Furthermore, we argue that Psillos' arguments for his claim that constructive empiricism itself needs abduction point up his failure to recognize the importance of van Fraassen's broader epistemology for constructive empiricism. Towards the end of our paper we discuss the suspected relationship between constructive empiricism and scepticism in the light of this broader epistemology, and from a somewhat more general perspective.

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Elgin on Lewis' Putnam's Paradox

Journal of Philosophy 94 (1997), 85-93.

To read this paper on the Web, go to "Elgin" Brief outline:

I. 'Initial' form of Putnam's argument; tacit principle (EQ)

II. Restrictions to ideal theory play no role in the proof: what is their real function? (EQ) revised to (EQ*) to accomodate intended/unintended distinction. Result that if a theory is ideal, and this consists in "just more theory", then it is true by (EQ*) if true by (EQ).

III. The dilemma. Elgin accepts the dilemma but opts for other horn

IV. The form of a solution; Lewis' specific instantiation of the form and his two tasks. Elgin's aim: to show that the second task cannot be successfully completed regardless of how the first task is performed.

V. (EQ) reduces to absurdity. What about (EQ*)? The same argument shows that (EQ*) implies that there exists just one, unique admissible interpretation.

VI. There is a proper role, more or less, for (EQ) and its variants, which explains their appeal. The point about what that proper role is, is related to Tarski's conclusions about how to avoid semantic paradoxes, is easily obscured and, in some respects, subtle. Mysteries of translation of the T-sentence.

VII. Interpretation of a real theory. Sceptical doubts about whether we have managed to fix reference, with or without help of nature? Just what are the doubts we are meant to harbor? Incoherence of the demand.

VIII The 'carve at the joints' solution to why the T-sentences must all be true. Display of confusion in the reasoning that invites such a 'solution'

IX. Agreements and disagreements. Pragmatics.

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The False Hopes of Traditional Epistemology

Philosophy and Phenomenological Research 60 (2000), 253-280.

to read this on the web and skip the abstract, go to: "The False Hopes of Traditional Epistemology"

After Hume, attempts to forge an empiricist epistemology have taken three forms, which I shall call the First, Middle, and Third Way. The First still attempts an a priori demonstration that our cognitive methods satisfy some (weak) criterion of adequacy. The Middle Way is pursued under the banners of naturalism and scientific realism, and aims at the same conclusion on non-apriori grounds. After arguing that both fail, I describe the general characteristics of the Third Way, an alternative epistemology suitable for empiricism.

Identity over time: objective, subjective

. B. van Fraassen and I. Peschard , Go to article in Philosophical Quarterly 2008.
In philosophy of science, identity over time emerges as a central concern in two guises: as an ontological category in the interpretation of physical theories, and as a problem in epistemology with respect to the conditions of possibility of knowledge. In Reichenbach's and subsequent writers on the problem of indistinguishable particles in quantum physics we see the return of a contrast between Leibniz and Aquinas on the subject of individuation. The possibility that the principle of the identity of indiscernables can be rejected has certain logical difficulties, which inexorably lead us from ontology into epistemology.
          For the epistemological problem we must attend to the differences that emerged between the (neo-)Kantian and logical empiricist traditions, also most saliently displayed in Reichenbach's writings. After an examination of the contrast between Kant's and Leibniz' conceptions of empirical knowledge, specifically with respect to the irreducibility of spatio-temporal determinations, we explore an application of a neo-Kantian view to that same problem of indistinguishable particles in physics.

Laws and Symmetry

Synopsis (book):

Laws and Symmetry has three main objectives. The first is to show the failure of philosophical accounts of laws of nature. The second is to undercut the epistemological principles at work in arguments for the reality of laws of nature. The third objective, nearest to my heart, is to be constructive as well, and to contribute to an epistemology and a philosophy of science antithetical to such metaphysical notions as laws of nature. Part One, in which the first objective is pursued, was the main subject of discussion in the symposium to follow. In this Synopsis, therefore, I shall concentrate on that.

In my view, as presented in Chapter 1, the concept of a law of nature is an anachronism, its proper life belonging to the 17th and 18th Centuries. Laws of nature played an important role in the philosophical-scientific thinking of Descartes and Newton, and functioned for them as a central clue to the structure of science. At the same time, two developments threatened the status of law. One was the empiricist critique of necessity and causality, notions closely allied to that of law. The other was that science was rapidly gaining autonomy not only from theology but from all of philosophy, and was exploiting concepts and methods foreign to metaphysics. Pre-eminent here is the birth of the symmetry argument. (Discussion of this subject is begun in Chapter 1 and continued in Chapters 10, 11 and 12.) Modern physics argues from symmetry and continuity -- not from universality or necessity, natural kinds or essences, contingency or accident. The concept of a law of nature is a vestigial concept in contemporary science.

Chapter 2 collects the cluster of criteria for what laws must be and do, which are honored in the literature to some degree or other. We can divide the criteria to be met by any philosophical account of laws roughly into major requirements and secondary ones. The major criteria concern what I call the problems of inference and identification. The accounts must show that there is a valid inference from what laws there are to what regularities there are in the world. The account must also identify the relevant aspects of the world that constitute or give rise to its laws, if any. Typically these two tasks lead to a dilemma. If laws of nature are identified in terms of some sort of necessity in nature which is simply postulated as fact, then there is no logical reason to think that the inference from lawlike necessity to actuality is valid. (Calling the postulated factor "necessity" or "necessitation" does not help.) If on the other hand the semantic account of law statements is so constructed that the inference in question is logically valid, then typically the truth-conditions of law statements involve something unidentifiable. Chapters 3, 4, and 5 argue that leading contemporary attempts (by David Lewis, David Armstrong, and a host of others) fail to slip between the horns of this dilemma. Nor do they meet secondary criteria, such as showing that what they make out to be laws of nature are the targets reached, or even aimed for, in scientific inquiry.

Both Quine and Rorty have, in their different ways, proclaimed the death of epistemology. I think they are right about mainstream traditional epistemology. There Induction has given way to Inference to the Best Explanation (IBE) in the epistemology hospitable to realism, or to metaphysics in general. In my view, developed in Part Two, neither Induction nor IBE qualifies as a rational strategy for change of opinion. To that extent at least I endorse some of Quine's and Rorty's conclusions. But it also seems to me that the underground river of probabilism, slowly growing in force over three centuries, has burst forth above ground in the twentieth century and brought new hope for epistemology. In Part Two I argue that with the end of foundationalism, probabilism provides the framework for a new epistemology, which is also adequate for philosophy of science.

The remainder of the book (Chapters 8-13) is devoted to contributions to the semantic approach in philosophy of science, to support my call to leave metaphysics behind. The semantic approach does not require an anti-realist or anti-metaphysical stance. In fact it is also followed by philosophers with very different philosophical positions from my own. But that is just the point: this collaboration in philosophy of science is possible because the approach is in itself neutral, and does not presuppose metaphysical views. I will leave the details aside, since the present symposium concentrates on Part One, which was meant to be the destructive prelude to this constructive effort in philosophy of science.

For current availability, Laws and Symmetry

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The Manifest Image and the Scientific Image

pp. 29-52 in D. Aerts (ed.). Einstein Meets Magritte: The White Book -- An Interdisciplinary Reflection. Dordrecht: Kluwer, 1999.

To read this on the web, go to "The Manifest Image and the Scientific Image"


There are striking differences between the scientific theoretical description of the world and the way it seems to us. The consequent task of relating science to 'the world we live in' has been a problem throughout the history of science. But have we made this an impossibility by how we formulate the problem? Some say that besides the successive world-pictures of science there is the world-picture that preceded all these and continues to exist by their side, elucidated by more humanistic philosophers. Wilfrid Sellars codified this conviction in his dichotomy of scientific image and manifest image. Others say that all our world-pictures are transient, evolve, conflict with and replace each other, undergo violent revolutions as well as periods of normal development, and may be incommensurable, allowing of no meaningful dialogue. All such formulations may themselves be tendentious metaphysics, full of false contrasts. Insistence on a radical separation between science and what we have apart from science, on the impossibility of accommodating science without surrender, may be a way of either idolizing or demonizing science rather than understanding it.

Modal Interpretation of Repeated Measurement:

Rejoinder to Leeds and Healey

Philosophy of Science (sched. for 1997).

A recent article (Leeds and Healey, 1996) argues that the modal interpretation (Copenhagen variant) of quantum mechanics does not do justice to immediately repeated non- disturbing measurements. This objection has been raised before, but the article presents it in a new, detailed, precise form. I show that the objection is mistaken.

Putnam's Paradox: Metaphysics Revamped and Evaded

to appear in Philosophical Perspectives,vol. 11 (Boston: Blackwell, 1997), pp. 17-42.

To read this paper on the Web, go to "Putnam's Paradox" ABSTRACT

In Putnam's paper "Realism and Reason" he gave an argument ("the model theoretic argument" it is sometimes called) which he intended as a refutation of metaphysical realism. Unfortunately it seemed to leave everyone, realists or not, in a difficult position. David Lewis called the argument "Putnam's paradox" and advanced a solution (also suggested by Gary Merrill): a bit more realism about the structure of the world or of nature will block the argument. In this way Putnam's argument was turned into putative support for a brand of realism, supposedly the only means to escape its apparently disastrous implications. I offer a different reading of the argument, with a non-realist escape from paradox as well as an (unsympathetic) diagnosis of the realist response.

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Structure and Perspective: Philosophical Perplexity and Paradox

pp. 511-530 in M. L. Dalla Chiara et al. (eds.) Logic and Scientific Methods. Dordrecht: Kluwer, 1997.

to read this paper on the web, and skip the abstract, go to "Structure and Perspective: Philosophical Perplexity and Paradox"

This paper has two abstracts


In reaction to revolutionary developments in modern science, both philosophers and scientists have suggested that science describes only the structure, as opposed to content, of the world. The described structure is structure invariant under changes of perspective (frames of reference, observers, alternative measurement set-ups). Extrapolating the view too far, the disappearance of content and of individual perspective leaves us with structure itself as surrogate content for a logically incoherent view from nowhere. Both empiricism and scientific realism face a quandary, with attempts to find a 'foundation' for science outside what is described in physical theory (whether qualities of experience or a postulated 'ready-made' world) notably lacking in success. I this paper I shall re-examine the prospects for a view of science which is empiricist but not foundationalist.


Structuralism (one variety of): the view that science describes only the structure (and not the content) of its domain. A view entangled from the beginning with the view that science is a representation of nature.

There were and are good reasons to be attracted to structuralism. But it needs to be explained, for as stated it rests on an obscure and possibly untenable distinction between structure and content.

Problem: attempts to make it precise have tended to reduce it to absurdity. Example: the Ramsey sentence view is a moderate form of structuralism. Lewis' postulate of natural classes can then be read as an attempt to rescue it from the reductio. Elgin's criticisms and Laurie Paul's 'symmetry' objection may be read as saying that this sort of rescue cannot work.

My Problem: my view of science belongs to the "semantic approach" which is pretty clearly a form of structuralism (though certainly as moderate as the Ramsey sentence version, in its deference to our understanding of "old" terms). I argue that it does not reduce to absurdity because the structuralism pertains to the raw materials for representation (the models which are used to represent) and not to the representing activity.

========= PS: the first section of "From Vicious Circle ..." is a further reflection on this topic.

What Is Empiricism, and What Should it Be?

Note: this has now been incorporated in The Empirical Stance, forthcoming Yale University Press, April 2002.


The history of the word "empiricism" does connect with a recognizable if somewhat vague tradition in philosophy. Nevertheless, the 'official' criterion by which historians started classifying philosophers in this way does not work very well. We need to ask what it is to belong to this tradition, in view especially of how it might have options for creative development from here on.

It is necessary first of all to examine arguments to the effect that there cannot be a coherent empiricist position at all -- I take such arguments to be very successful, but predicated on an understanding of what it is to take a philosophical position which is itself dubitable. In response I shall try to sketch how a range of empiricist positions can in principle be developed, concentrating on three main problems that I take to be common to all.

The first two are epistemological, and relate to generalizations of the idea of scientific method: does adoption of method entails a grounding belief? and what could be the epistemic attitude empiricists identify as characteristically scientific, nl. 'undogmatic belief'? The third is a meta- problem: just what will it be, according to the empiricist, to 'do' philosophy? How will his or her empiricism be manifest in philosophical practice? This third problem arises exactly because of the necessary rejection, noted above, of a certain traditional understanding of what it is to take a philosophical position.

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