CONSIDER three statements, each of which, in its different way, expresses a view that moral opinions, or moral judgements, or moral outlooks are ‘merely subjective’:

1. (a) A man's moral judgements merely state (or express) his own attitudes.

2. (b) Moral judgements can't be proved, established, shown to be true as scientific statements can; they are matters of individual opinion.

3. (c) There are no moral facts; there are only the sorts of facts that science or common observation can discover, and the values that men place on those facts.

The three statements come very close to one another, and in discussions of subjectivism and objectivism one often finds versions of the three being used virtually interchangeably. They are, indeed, genuinely related to one another. Yet they are significantly different. The first, (a), expresses what might be called in a broad sense a logical or linguistic view: it purports to tell us something about what moral remarks are or do. The second, (b), introduces a set of notions not present in the first, notions connected with the concept of knowledge, and may be taken to express an epistemological view about moral judgements. The third statement, (c), is the vaguest and least tangible of the three, and shows on its surface the danger of collapsing, partly or completely, into one or other of the first two: which is what many philosophers would claim it must do.