 For Cohen in the Logic, the principles that constitute the object of mathematical natural scientific knowledge must be generated by pure thinking, since only then can we have a priori knowledge of that object (Beiser 2018, 196–7). But Cohen’s methodological rationalism gives us another way to understand why those principles must be generated by pure thinking. To say that pure thinking is independent of any influences external to thought or reason is to say that pure thinking makes a rational demand: it can accept no representations that are given, brute, or unexplained. When Cohen asserts that pure thinking generates the principles that constitute the object of mathematical natural science, he means that no part of that object has its source outside of pure thinking and thus no part of it can be left as given or unexplained. For Cohen, then, pure thinking is not so much a species of cognitive content so much as it is a methodological demand. (See Beiser 2018, [Ch. 11] for a detailed account of pure thinking as regulative.)