Interdisciplinarity constitutes a common and fertile scientific practice; accordingly, there are numerous interdisciplinary theories, but there is no theory of interdisciplinarity. Essays on interdisciplinarity speak of an approach destined to save the world, dichotomize monodisciplinarity and interdisciplinarity, or draw typologies of interdisciplinary work. However, they do not generate theories of interdisciplinarity. In fact, the project of such a theory is absurd because if scientific theories exist, a theory of science cannot. This is what the current paper will argue.