Samuel Mitchell

Van Fraassen stresses two distinct but interrelated themes in The Scientific Image: the semantic view of theories and the epistemic status of unobservables. The first of these could easily be accepted by a scientific realist, and indeed realists like Giere have already adapted it to their purposes. So the specifically empiricist thread in van Fraassen’s philosophy stems from the second.Van Fraassen breaks from tradition in founding his empiricism not on the ontological status of unobservable entities but on the epistemic attitude we take to them. The main points of his position are these:1)The claims of scientific theories, including claims about unobservable entities, are to be taken literally. Theories are not reconstructed so as to remove claims of the existence of unobservable objects.2)Observation is a matter of direct observation by accepted participants in the human scientific community.

The Quine-Duhem thesis states that we always have a choice about how praise or blame are distributed in cases of scientific justification. But in many scientific examples, there is simply no room to doubt that a particular hypothesis is responsible for a refutation or established by the observations. Fault Tracing gives a theory of independent justification from different sets of evidence. Using both real and artificial examples, it shows how to play independently established hypotheses against each other to determine whether an arbitrary hypothesis needs to be altered in the light of (apparently) refuting evidence. This is a theory of the functioning of background knowledge in scientific justification, which allows for justification from the evidence independently of values. The book ends by briefly discussing the significance of these results in metaphysics and philosophy.

This article argues against Nina Emery’s view that there are compelling reasons to believe in nomological probabilities. To the degree that we can see no other way to detect the occurrence of the explanans apart from the bare fact that the explanandum happened, we may be skeptical that the proposed explanation is correct and open to the possibility that there is none. This provides us with a way to distinguish physical entities from mathematical ones, illuminating interpretations of quantum mechanics.

Van Fraassen's constructive empiricism is presently the most influential and well-developed alternative to scientific realism. In this paper I argue that a reasonable condition on the distinction between belief and agnosticism prevents van Fraassen from claiming that we can be agnostic about what a theory says about unobservable entities while simultaneously accepting that theory. The upshot is that we must find some other way to do justice both to the argument for constructive empiricism and to van Fraassen's cogent criticisms of scientific realism. I suggest that a highly attractive alternative is founded upon semantic anti-realism, and that empiricists should develop this alternative.