Book excerpt: Medieval Skepticism, and the Claim to Metaphysical Knowledge presents three sets of essays. The first is an exchange between Antoine Côté and Charles Bolyard over Siger of Brabant’s strategy to silence the skeptic by discriminating between nobler and lesser senses and grounding certitude in sense perceptions. Second is another scholarly exchange, between Rondo Keele and Jack Zupko, over what Keele describes as Walter Chatton’s attempt to discredit Ockhamist nominalism by means of both an ‘anti-razor’, employed by Chatton to prescribe ontological commitment, and an argument strategy based on iteration and infinite regress. The last group of essays explores issues that develop out of the metaphysics of Thomas Aquinas. Joshua Hochschild defends several key positions of Thomistic metaphysics against Anthony Kenny’s criticism that Aquinas’s treatment of being is inadequate, incoherent or even sophistic. Similarly, David Twetten, after laying out Aquinas’s nine versions of the proof for the Real Distinction between essence and esse, suggests one way in which Aquinas could meet the Aristotelian’s formidable ‘Question-Begging Objection’. Lastly, Scott M. Williams contends that to preserve God’s perfect knowledge of individual material creatures, Aquinas must alter his account of the unintelligibility of prime matter in the individuation of material creatures.