 Crucially, rational wills that are negatively free must be autonomous, or so Kant argues. This is because the will is a kind of cause—willing causes action. Kant took from Hume the idea that causation implies universal regularities: if x causes y, then there is some universally valid law connecting Xs to Ys. So, if my will is the cause of my φing, then Φing is connected to the sort of willing I engage in by some universal law. But it can’t be a natural law, such as a psychological, physical, chemical or biological law. These laws, which Kant thought were universal too, govern the movements of my body, the workings of my brain and nervous system and the operation of my environment and its effects on me as a material being. But they cannot be the laws governing the operation of my will; that, Kant already argued, is inconsistent with the freedom of my will in a negative sense. So, the will operates according to a universal law, though not one authored by nature, but one of which I am the origin or author. And that is to say that, in viewing my willing to φ as a negatively free cause of my φing, I must view my will as the autonomous cause of my having φed, as causing my having φed by way of some law that I, insofar as I am a rational will, laid down for my will.