Bas C. Van Fraassen

Explanatory power is a complex theoretical virtue, not reducible to empirical strength or adequacy, which includes other virtues as its own preconditions. Since this virtue provides one of the main criteria by which theories are evaluated, it presents thus a challenge to any empiricist account of science. After a critical account of attempted explications of the concept of scientific explanation, this chapter offers a pragmatic account that identifies explanations with answers to why‐questions. Since such questions are set by the questioner, and have their family of relevant direct answers determined by the presuppositions, values, and interests involved in the questioning, that makes explanation relative to contextual factors. On this understanding, evaluations of scientific explanation cannot play the role required for their use in support of scientific realism––and, incidentally, the large array of standard puzzles in the literature on this subject are solved.

ABSTRACT For changing opinion, represented by an assignment of probabilities to propositions, the criterion proposed is motivated by the requirement that the assignment should have, and maintain, the possibility of matching in some appropriate sense statistical proportions in a population. This ‘tracking’ criterion implies limitations on policies for updating in response to a wide range of types of new input. Satisfying the criterion is shown equivalent to the principle that the prior must be a convex combination of the possible posteriors. Furthermore, this is equivalent to the requirement that prior expected values must fall inside the range spanned by possible posterior expected values. The tracking criterion is liberal; it allows for, but does not require, a policy such as Bayesian conditionalization, and can be offered as a general constraint on policies for managing opinion over time. Examples are given of non-Bayesian policies, both ones that satisfy and ones that violate the criterion. _1_ Introduction _2_ Alternative Updating Policies _3_ Modelling the Situation for Normal Updating _4_ Tracking: A Criterion for Updating Policies _5_ Tracking: Precise Formulation and Relation to Convexity _6_ The Spanning Criterion _7_ Non-Bayesian Policies that Satisfy the Spanning and Tracking Criteria _8_ Policies that Violate the Spanning and Tracking Criteria Appendix Appendix

I exist, but I am not a thing among things; X exists if and only if there is something such that it=X. This is consistent, and it is a view that can be supported. Calvino’s novel The Non‐Existent Knight can be read so as to illustrate this view. But what is my relation to the things there are if I am not identical with any of them – things such as my arms, my garden, the city I live in? I name this the Gurduloo problem, after the Knight’s page. This relation must be one that admits of degrees; I suggest that we say that I manifest myself through the things thus associated with me. Several pseudo‐problems, pertaining to volitional action, supervenience, observability, and the emergence of consciousness, dissolve upon inspection.

What is empiricism and what could it be? Bas C. van Fraassen, one of the world's foremost contributors to philosophical logic and the philosophy of science, here undertakes a fresh consideration of these questions and offers a program for renewal of the empiricist tradition. The empiricist tradition is not and could not be defined by common doctrines but embodies a certain stance in philosophy, van Fraassen says. This stance is displayed first of all in a searing recurrent critique of metaphysics, and second in a focus on experience that requires a voluntarist view of belief and opinion.

What is empiricism and what could it be? Bas . van Fraassen, one of the world’s foremost contributors to philosophical logic and the philosophy of science, here undertakes a fresh consideration of these questions and offers a program for renewal of the empiricist tradition. The empiricist tradition is not and could not be defined by common doctrines, but embodies a certain stance in philosophy, van Fraassen says. This stance is displayed first of all in a searing, recurrent critique of metaphysics, and secondly in a focus on experience that requires a voluntarist view of belief and opinion. Van Fraassen focuses on the philosophical problems of scientific and conceptual revolutions and on the not unrelated ruptures between religious and secular ways of seeing or conceiving of ourselves. He explores what it is to be or not be secular and points the way toward a new relationship between secularism and science within philosophy.

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 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 shall describe the general characteristics of the Third Way, an alternative epistemology suitable for empiricism

In The Inference That Makes Science, Ernan McMullin recounts the clear historical progress he saw toward a vision of the sciences as conclusions reached rationally on the basis of empirical evidence. Distinctive of this vision was his view of science as driven by a specific form of inference, retroduction. To understand this properly, we need to disentangle the description of retroductive inference from the claims made on its behalf. To end I will suggest that the real rival to McMullin's vision of science is not the methodologies he criticizes so successfully but a more radical empiricist alternative in epistemology