 It can be difficult to see how this method allows for any philosophically critical evaluation of theories in the history of science – a kind of evaluation Cohen never shies away from. On the transcendental method, philosophy does not seek philosophical grounds for casting doubt on or rejecting mathematical or scientific theories. Rather, it starts by taking those theories and their objectivity for granted. It starts with them as facts, as explananda in need of philosophical explanation. But Cohen often criticizes and rejects theories he does not like, and does so for apparently philosophical reasons. This is especially clear in the historical sections of his 1883 Principle of the Infinitesimal Method and its History, where Cohen uses apparently philosophical principles to criticize and reject various efforts in the history of mathematics to define, for example, limits and infinitesimals. But Cohen’s criticisms do not violate the transcendental method. The principles that serve as the basis for his criticisms emerge from a philosophical investigation of theories given in the history of science. They are thus principles that turn out to be required for the philosophical explanation of those theories and their objectivity.