This paper replies to Peter Millican (Mind, 2009), who argues that Hume denies the possible existence of causal powers which underlie the regularities that we observe in nature. I argue that Hume's own philosophical views on causal power cannot be considered apart from his mitigated skepticism. His account of the origin of the idea of causal power, which traces it to a subjective impression, only leads to what he calls ‘Pyrrhonian scepticism’. He holds that we can only escape such excessive (...) skepticism by way of a natural judgment based on the association of ideas, which forms the basis of what he calls ‘a legitimate ground of Assent’. (shrink)