This paper offers a reevaluation of the debate between assimilationism and differentialism concerning the anthropological difference. Both sides usually assume that the difference consists in a capacity which humans possess and other animals lack, and that is added to a set of capacities humans share with other animals. A likely candidate for this role is reason. An additive conception of human reason on these lines runs into several difficulties, which can be avoided by thinking of reason transformatively, as providing human capacities with a special rational form. What such a transformative conception amounts to is described in some detail for the special case of human perception. A transformative understanding of reason’s role enables us to formulate a differentialist position that does not fall prey to the usual problems of differentialism.