This essay explores the dialectics of theory and practice in terms of argumentation theory. Adapting Jonsen and Toulmin's (1988) notion of a Theory-Practice spectrum, it conceives Theory and Practice as extreme ends of a continuum and discourses as falling at various points along the continuum. Every theoretical discourse has essential practical aspects, and every practical discourse has essential theoretical aspects. Practices are theorized to varying degrees but every practice is theorized to some degree. Reflective discourse, which is discourse about practice, moves to and fro along the Theory-Practice continuum. Reflective discourse involves argumentation. Practical argumentation connects theory to practice; it appeals to general warrants, which may be simple or may tap into elaborate conceptual structures, in order to establish grounds for practical judgments. A practical discipline is a relatively coherent intellectual-professional enterprise that cultivates a field of social practice by engaging within itself and with practitioners in a reflective discourse. The argumentation of a practical discipline, like ordinary practical reflection, moves to and fro along the Theory-Practice continuum but in more methodical steps informed by systematic methodological reflection on the reflective process itself.