Unconceived alternatives and the cathedral problem

Abstract

Kyle Stanford claims we have historical evidence that there likely are plausible unconceived alternatives in fundamental domains of science, and thus evidence that our best theories in these domains are probably false. Accordingly, we should adopt a form of instrumentalism. Elsewhere, I have argued that in fact we do not have historical evidence for the existence of plausible unconceived alternatives in particular domains of science, and that the main challenge to scientific realism is rather to provide evidence that there are likely not plausible unconceived alternatives. In the present paper, I contend that we may come to have such evidence in the long run of science. I then investigate the epistemic consequences of the claim that we presently do not have evidence for or against the existence of plausible unconceived alternatives, but that in the future we may come to have evidence against the existence of plausible unconceived alternatives. I argue there are prima facie reasons to endorse a form of voluntarism in this situation according to which scientists and others may rationally be more optimistic or more pessimistic about the truth of our best theories, on the grounds that the widespread acceptance of an obligation to be an instrumentalist threatens to disrupt the proper functioning of science, in part because the domain of application of the problem of unconceived alternatives is unclear.