Abstract

Over the last twenty years, Bas van Fraassen has developed a “new epistemology”: an attempt to sail between Bayesianism and traditional epistemology. He calls his own alternative “voluntarism”. A constant pillar of his thought is the thought that rationality involves permission rather than obligation. The present paper aims to offer an appraisal of van Fraassen’s conception of rationality. In section 2, I review the Bayesian structural conception of rationality and argue that it has been found wanting. In sections 3 and 4, I analyse van Fraassen’s voluntarism. I raise some objections about van Fraassen’s reliance on prior opinion and argue that the content of a belief matters to its rationality. In section 5, I criticise van Fraassen’s view that inference to the best explanation is incoherent. Finally, in section 6, I take on van Fraassen’s conception of rationality and show that it is too thin to fully capture rational judgement.