What you don't know can't hurt you: realism and the unconceived

Two of the most potent challenges faced by scientific realism are the underdetermination of theories by data, and the pessimistic induction based on theories previously held to be true, but subsequently acknowledged as false. Recently, Stanford (2006, Exceeding our grasp: Science, history, and the problem of unconceived alternatives. Oxford: Oxford University Press) has formulated what he calls the problem of unconceived alternatives: a version of the underdetermination thesis combined with a historical argument of the same form as the pessimistic induction. In this paper, I contend that while Stanford does present a novel antirealist argument, a successful response to the pessimistic induction would likewise defuse the problem of unconceived alternatives, and that a more selective and sophisticated realism than that which he allows is arguably immune to both concerns.