I will introduce my current book project, Writing the Rules of Reason: Inscriptive Practice and the Rise of Mathematical Logic, in which I show how logic became a mathematical science and what that transformation meant for enterprises ranging from speculative philosophy to automated computing. Between the mid nineteenth century and the outbreak of World War II, scholars across Europe and North America replaced the venerable prose-based logic of Aristotle with a new and thoroughly mathematical enterprise. I approach this transformation on the level of practices, tracking how writers developed new symbolic systems for representing logic on paper—systems that eventually became not just tools but objects of scientific inquiry. Each new notation entailed a way of interacting with marks on paper, a manner of training students, and a vision for why people might need a science of logic. I argue that ultimately the proliferation of notations disciplined students to see any given symbolic system as contingent, and to see potential in that contingency. The diversity of the writing practices through which logic became transformed it into a discipline that not only employed symbolic systems but took such systems as its fundamental concern.