Counterfactuals, Modal Knowledge, and Understanding

In this essay, I attempt to diagnose and show the importance of a structural problem that affects Williamson’s counterfactual epistemology of modality. First, I provide a general, even if somewhat heuristical, description of the requirements that a realist epistemology of modality must fulfil. The requirements are analyzed and used for interpreting various controversial choices that Williamson and other philosophers make when theorizing modal knowledge. I then proceed to explain why a more thorough examination of the integration of Williamson’s view of understanding and of his restrictive epistemology of modality leads to the uncovering of a tension that jeopardizes Williamson’s robust realist tenets. I argue that a similar problem (or perhaps different problems with similar underlying reasons) befalls other realist accounts and show why various extant solutions are insufficient. The paper concludes with a reappraisal of the tasks that modal epistemologists have hitherto ignored or treated only collaterally, which may also be interpreted as a critical analysis of the limits of older and newer conceptions of metaphysical modality.