C L Stevenson: the Emotive Meaning of Ethical Terms

C. L. Stevenson: The Emotive Meaning of Ethical Terms
Stevenson claims that before we can hope to answer ethical questions, we must first try to understand exactly what is being asked. In light of this, he examines the question: what does it mean to call something good? According to interest theories, to say that something is good is simply to say that it is approved of or desired, either by the speaker or by some group of people. Stevenson denies that such theories can fully capture what it means to call something good, and sets out to provide a more satisfying theory. He claims that any such theory must account for three things: (i) people may sensibly disagree about what is good, (ii) goodness has a "magnetism" in that judgments about goodness motivate us to act, and (iii) claims about goodness are not empirically verifiable. Stevenson believes his theory, emotivism, meets these requirements. According to emotivism, ethical claims are not simply attempts to describe the world, but are primarily used to influence others. As Stevenson puts the point, "ethical terms are instruments used in the complicated interplay and readjustment of human interests."
Stevenson maintains that ethical terms have emotive meanings, in the sense that they tend to produce affective responses in people. We use these emotive meanings to try to influence others to approve or disapprove of certain things. Thus, on Stevenson's view, to claim that something is good is both to express one's own approval of the thing, as well as to encourage one's audience to join in approving of it. Moral disagreements are therefore not mere disagreements in belief, in which one person believes a proposition and the other one disbelieves it. Rather, in ethical disagreements, one person has a favorable attitude toward something, whereas the other has an unfavorable attitude, and neither is content to let the other's attitude remain.
-What account does Stevenson give of the nature of ethical disagreements? How does ethical disagreement differ from scientific disagreement, on his view? To what extent does he think it is possible to argue about ethics?