 With the Principle of Consciousness Reinhold believed he had uncovered that “common root” of thought and sensibility, which Kant had declared to be unknowable (CPR A 15/B 29). By commencing his analysis at the level of “representations as such,” Reinhold was convinced that he had, so to speak, hit philosophical rock bottom, inasmuch as all consciousness is self-evidently “representational” in character. (Fichte, however, in his Aenesidemus review and his early writings on the Wissenschaftslehre, would subsequently challenge precisely this claim.) Thus, Reinhold’s “Theory of Representation” (which is the first part of the Elementary Philosophy) purports to provide Kant’s Critical philosophy with the very foundation it so sorely lacks. And the Principle of Consciousness is, in turn, the foundational or first principle of this new Theory of Representation—and hence the first principle of philosophy as a whole.