An influential strand in philosophy of science claims that scientific paradigms can be understood as relativized a priori frameworks. Here, Kant’s constitutive a priori principles are no longer held to establish conditions of possibility for knowledge which are unchanging and universally true, but are restricted only to a given scientific domain. Yet it is unclear how exactly a relativized a priori can be construed as both stable and dynamical, establishing foundations for current scientific claims while simultaneously making intelligible the transition (...) to a subsequent framework. In this article, I show that important resources for this problem have been overlooked in Kant’s theory of reflective judgement in the third Critique. I argue that Kant accorded the task of formulating new scientific laws to reflective judgement, which is charged with forming new ‘universals’ that guide the experience of nature. I show that this is the very task attributed to the relativized a priori: the constitution of a given conceptual framework, not of the conditions for object-reference as such. I conclude that Kant’s considered conception of science encompasses the operations of both reflective and determining judgement. Relativizations of the a priori should follow Kant’s lead. (shrink)