 Cohen has a striking view of what a priori laws of the third level actually consist in, and of the possible experience they are constitutive of. Although he would emphasize this striking view more in later writings it is nevertheless explicit in the first edition of his Kant’s Theory of Experience. He did not think the third level of the a priori consists in cognitive structures in the subject’s mind, structures we could discover by doing physiology (as, for example Helmholtz and Lange thought) or by introspection (as, for example, J.F. Fries and, in Cohen’s own time, Jürgen Bona Meyer thought) (de Schmidt 1976: Ch. 2.3). Rather, he insisted that these a priori laws were the principles of mathematics and the fundamental laws of pure natural science, that is, mechanics. Further, these principles and laws are constitutive of the possibility of experience in a very specific and, Cohen insists, Kantian sense of “experience”: for Cohen, experience consists in the theories furnished by the mathematically precise science of nature, considered as if laid out “in printed books” (Cohen 1877, 27). That is, on Cohen’s interpretation, Kant’s a priori is not principally concerned with the cognitive activity of the knower. Rather, it consists in the laws of mathematically precise natural science considered independently of – as if free-floating from – the mind of any particular knower. (At the same time, Charlotte Baumann (2019) argues that, in at least some of his writings, Cohen does retain some concern with the role of sensation in experience.)