Whereas Parts 1 and 2 examined the “origin and foundation of our judgments concerning the sentiments and conduct of others,” Part 3 examines “the origin of those concerning our own” (109). Smith argues that the “principle” by which we judge our own conduct “seems to be altogether the same” as that by which we judge others (109). When judging our own conduct, we view ourselves as the “impartial spectator” would view us (109). In fact, we divide ourselves into “spectator” and “agent” (111).

Human beings desire praise, but in the exercise of their moral judgment, they prefer praiseworthiness. “Nature,” it seems, “endowed” us “not only with a desire of being approved of, but with a desire of being what ought to be approved of” (114-15). Indeed, the desire for undeserved praise springs only from “the most contemptible vanity” (115). In like manner, human beings wish to avoid blameworthiness, of being “the just and proper objects of the hatred and contempt of our fellow creatures” (115). Even worse than blameworthiness is “[u]nmerited reproach” (117), for “the innocent man […] is tormented by his own indignation at the injustice which has been done to him” (118), in which case “the only effectual consolation […] lies in an appeal to a still higher tribunal, to that of the all-seeing Judge of the world, whose eye can never be deceived, and whose judgments can never be perverted” (125).