It is, however, in the “Essays on the Active Powers of Man,” by Thomas Reid (1710-1796) that the commonplace notion of conscience receives its principal philosophical support. Concerning this “moral sense,” as Reid calls it in reminiscence of Shaftesbury, the following formidable assertions are made. In the first place, “It is without doubt far superior to every other power of the mind.” In the second place, “The testimony of this moral sense,” like that of the rest of the senses, “is the testimony of nature, and we have the same reason to rely upon it.” In addition, just as the sense of vision is fundamental for space perception, so “The truths immediately testified by our moral faculty are the first principles of all moral reasoning.” Reid would also have us note that this reasoning is not inductive, but deductive, for he says, “The first principles of morals are the _immediate_ dictates of the moral faculty.” The outstanding fault of such a theory is that it assumes that every name we choose to manufacture has a reality corresponding to it. This is the fallacy of hypostatization, to which all idealistic philosophers are addicted. Granted that it is true, as Butler says, that we approve and disapprove of some of our actions, yet this does not imply that there is a transcendent faculty within us which we are at liberty to substantialize as Conscience or a Moral Sense. Such language is merely noun-worship. It is granted that the words “moral” and “sense” have each separately a meaning, but it does not follow that the compound term “moral-sense” must therefore have one. Moreover, all of these intuitionists are wilful and unperspicuous rationalists, demanding a fundamental principle in ethics _before_ they have employed any induction or experimentation that might help them to frame such a principle correctly. They are willing to do no hard work, and to perform no crucial tests in order to see whether their guesses are facts or fictions. To complete our criticism, we must not omit to state that Reid’s elevation of conscience to a place among the senses merely reveals the extent to which he was willing to go in his defence of the testimony of the senses in general against the idealists of his age. His use of the “moral sense” was a debater’s trick. The high esteem in which conscience was held by his antagonists tempted him to turn one of their own weapons against them.