The aim of this paper is to propose a novel reading of the critical legitimacy of the regulative use of reason in the Transcendental Dialectic of Kant's Critique of Pure Reason. After introducing some key terminology of the Dialectic, I analyse the shortcomings of two influential accounts of the regulative use of reason and identify their common problem in their commitment to the descriptivity of the ideas of reason. I then offer my rule‐based account of the regulative use of reason (...) by clarifying how Kant transforms reason's metaphysical inclinations into prescriptive rules of bottom‐up empirical research. Finally, I explain why such interpretation of reason is metaphysically innocent and thereby a promising approach to understand its role in Kant's scientific project. (shrink)