 Further, Cohen identifies the a priori of his third level, the laws of mathematical natural science, with the synthetic a priori principles Kant thinks mathematical natural science contains. Cohen says of these synthetic a priori principles that they are “that which is present” in experience (Cohen 1987 [1871b], 206). So philosophy seeks to explain the possibility of experience by identifying and articulating the a priori laws “present” in it. As Cohen would later put it, experience, conceived as the evolving doctrines of mathematical natural science, is “given as a task” [aufgegeben] to philosophy: while experience is given with synthetic a priori principles already contained in it, it is the task of philosophy to identify and articulate those principles, and in so doing to explain how they make objective experience possible.