  Here are few of the problems. If it is reasonable to obey conscience, then “the rules that Conscience lays down” are either reasonable in and of themselves or they are “the dictates of an arbitrary authority” (Sidgwick, III.13 §2). If the latter, then it is hard to see what justifies this arbitrary authority. But if the former, then Sidgwick argues that there is no independent moral authority for conscience — a conclusion which Sidgwick thought perfectly reasonable — and Butler is caught in the same justificatory circle that the Stoic arguments for life according to nature were: “it is reasonable to live according to Nature, and it is natural to live according to Reason” (ibid.). A related objection is that since both conscience and self-love are rational principles and in general cannot be in conflict, conscience just dictates whatever self-love dictates and vice-versa. Consequently conscience cannot have a distinctive authority. Sturgeon identified a different circularity connected with the justification of the supremacy of conscience. Since Butler held that virtuous actions are those in conformity to the nature of the agent and vicious ones not in conformity, according to Sturgeon “the doctrine of natural authority of conscience is entirely superfluous” (Sturgeon, 316). This is because if conscience points to the wrongness of an action the wrongness must be due to the action’s conformity or non-conformity with our nature — i.e. due to a conflict among principles. Conscience can’t be pointing to a conflict with itself since that would be circular.  So it must be a conflict with the next highest principle: self-interest. But then conscience just asserts what self-interest dictates, and so the testimony of conscience is redundant and has no special authority. Put differently, Butler assumes that his argument that virtue is natural entails an argument for the supremacy of conscience. But there is no good reason to assume the entailment — in fact the two are not only independent, but in conflict. There have been a number of responses to Sturgeon. Penelhum, notably, denied that Butler was committed to the “Full Naturalistic Thesis” and argued that Butler instead held “the independent existence of the judgments of right and wrong” from judgments of “naturalness and unnaturalness” (Penelhum 1990, 68; see also Irwin 2008 §707 and McNaughton 2012).