Abstract

We know a great deal about what is possible, so modal knowledge must be possible, not just in principle but by ordinary methods. Christopher Peacocke’s leading thought in Chapter 4 of Being Known is that this fact places significant constraints on philosophical treatments of modality. Modal realism is ruled out on the ground that it renders modal truth “radically inaccessible”, and actualism is forced upon us. It goes without saying that any account of the modal facts must eventually dovetail with some account of how we know them. But Peacocke’s approach is animated by the thought that there is a mystery about modal knowledge—a transposed version of Benacerraf’s puzzle about mathematical knowledge under Platonism. Peacocke clearly believes that modal realism renders the problem intractable. But what exactly is the mystery in the modal case? And why exactly does modal realism preclude a solution? Peacocke himself does not say. The ‘access problem’ for modal realism is clearly decisive for him; but it is very much in the background. Nonetheless, for several reasons, it will help to start here.