In April 1725, shortly after the publication of Hutcheson's Inquiry, the rationalist philosopher Gilbert Burnet published a letter in the London Journal in which he raised a number of objections to Hutcheson's position. Hutcheson responded to Burnet's letter, Burnet responded to Hutcheson's response, and Hutcheson responded once again. Hutcheson then incorporated much of what he said in the letters in his Illustrations upon the Moral Sense, which was published in 1728.

In Section A of this chapter, I outline Burnet's initial rationalist criticisms of Hutcheson's moral sense theory. In B, I explain Hutcheson's first response to Burnet, which is based on a claim about morality that is a clear descendant of Cudworth's 1647 sermons and Shaftesbury's sentimentalist moral psychology and an even clearer ancestor of Hume's “motivational argument” in 3.1.1 of the Treatise of Human Nature. In C, I show how Burnet countered Hutcheson's response, with an eye toward elucidating the similarity between Burnet's rationalism and the moral rationalism of Cudworth's EIM. And in D, I explain Hutcheson's response, which consists of an argument that is not only a clear precursor to Hume's “content” arguments of 3.1.1 of the Treatise but itself a devastating blow to that rationalist position.

Burnet's Initial Rationalist Criticism of Hutcheson's Moral Sense Theory

In the Inquiry, Hutcheson had contended that the moral distinctions we make are based on our moral sense: when something elicits from our moral sense the pleasurable feeling of approval we think it virtuous, and when something elicits from our moral sense the painful feeling of disapproval we think it vicious.