By Katharina T. Kraus

This paper shows why Kant’s critique of empirical psychology should not be read as a scathing criticism of quantitative scientific psychology, but has valuable lessons to teach in support of it. By analysing Kant’s alleged objections in the light of his critical theory of cognition, it provides a fresh look at the problem of quantifying first‐person experiences, such as emotions and sense‐perceptions. An in‐depth discussion of the mathematical principles, which define constitutive conditions for mathematical‐numerical experience in general, and their applicability to inner sense will demonstrate why it is in principle possible to justify a quantitative structure of psychological judgments on the grounds of Kant’s transcendental philosophy. In conclusion, it will propose how Kant’s critique could be used in a constructive way to develop first steps towards a transcendental foundation of psychological knowledge.