This article provides a comparative analysis of various methodologies employed in building arguments regarding prostitution law and policy, and reflects on the proper aims of legal philosophy more generally. Taking Peter de Marneffe’s Liberalism and Prostitution (OUP 2010 ) as a launching point for these reflections, the article offers a mostly favourable review of the book as a whole, and defends the philosophical method as one (amongst other) valuable ways to argue about prostitution.