Deflecting Ockham’s Razor: A Medieval Debate about Ontological Commitment

William of Ockham (d. 1347) is well known for his commitment to parsimony and for his so-called ‘razor’ principle. But little is known about attempts among his own contemporaries to deflect his use of the razor. In this paper, I explore one such attempt. In particular, I consider a clever challenge that Ockham’s younger contemporary, Walter Chatton (d. 1343) deploys against the razor. The challenge involves a kind of dilemma for Ockham. Depending on how Ockham responds to this dilemma, his razor will, Chatton argues, either prove unacceptably dull when it comes to determining ontological commitment or prove unacceptably sharp when it comes to determining commitments entailed by certain theological doctrines. While Chatton’s objection is subtle and interesting in its own right, the broader significance of the debate between these thinkers lies in the light it sheds on medieval approaches to issues surrounding metaphysical methodology.