Philosophy may relate to interdisciplinarity in two distinct ways On the one hand, philosophy may play an auxiliary role in the process of interdisciplinarity, typically through conceptual analysis, in the understanding that the disciplines themselves are the main epistemic players. This version of the relationship I characterise as ‘normal’ because it captures the more common pattern of the relationship, which in turn reflects an acceptance of the division of organized inquiry into disciplines. On the other hand, philosophy may be itself the site for the production of interdisciplinary knowledge, understood as a kind of second-order understanding of reality that transcends the sort of knowledge that the disciplines provide, left to their own devices. This is my own position, which I dub ‘deviant’ and to which most of this article is devoted. I begin by relating the two types of interdisciplinarity to the organization of inquiry, especially their respective attitudes to the history of science. Underlying the two types are contrasting notions of what constitutes the ‘efficient’ pursuit of knowledge. This difference is further explored in terms of the organization of the university. The normal/deviant distinction was already marked in the institution’s medieval origins in terms of the difference between Doctors and Masters, respectively, an artefact of which remains in the postgraduate/undergraduate degree distinction. In the context of the history of the university, the prospects for deviant interdisciplinarity were greatest from the early sixteenth to the early nineteenth century—the period called ‘early modern’ in the philosophy curriculum. Towards the end of that period, due to Kant and the generation of idealists who followed him, philosophy was briefly the privileged site for deviant interdisciplinarity. After Hegel’s death, the mantle of deviant interdisciplinarity increasingly passed to some version of ‘biology’. I explore the ‘Natur-’ and ‘Geisteswissenschaft’ versions of that post-philosophical vision, which continue to co-exist within today’s biological science. I then briefly examine the chequered reputation of Jean-Baptiste Lamarck, someone who exemplified the promise and perils of deviant interdisciplinarity over the past 200 years. I conclude with an Epilogue that considers contemporary efforts to engage philosophy in interdisciplinary work, invoking William James as an exemplar.