 In this passage, Reid tells us that Newton’s rules pertain only to the physical laws of nature and what is subsumable under them. But the rational principles of action, we have seen, are not themselves the physical laws of nature. They do not concern how the universe in fact operates. Rather, they concern how rational agents ought to conduct their behavior. Nor are these principles subsumable under Newton’s laws (EAP IV.ix: 251). They are, in Reid’s view, not part of the space/time manifold. It follows that Newton’s methods should not guide our theorizing about the rational principles of action. Since moral principles are among the rational principles of action, it follows that they are not identical with or subsumable under Newton’s laws. Given the additional assumption that natural science must conform to Newton’s rules, Reid concludes that morality is not the subject matter of natural science. That this is so, Reid continues, is “no reason to regret.” It is a matter of simply acknowledging the implications of Newton’s system—implications, Reid maintains, that philosophers such as Hume and Priestley, who also took themselves to be followers of Newton, had failed to appreciate.