This paper argues that historians of ideas must, when seeking to reconstruct webs of beliefs, interpret texts as though they were performances. As this is particularly the case with dialogic texts, the paper focuses on Plato's dialogues to show that the arguments expressed therein cannot be taken as expressions of Plato's beliefs. Rather, such arguments seek to prompt thought in their readers and thus reveal beliefs indirectly. We must therefore revise Mark Bevir's account of the reconstruction of webs of beliefs so that we construct a consistent web and then assume that to be the web of the author in question, rather than assuming that the web we construct is a consistent one. Consideration of Leo Strauss's argument that philosophers have often had to hide their meaning for fear of persecution, the paper concludes that its argument may apply to treatise-based writing as well as to dialogues. All texts include an element of the performative.