Value Theory (Axiology)

Core Idea

Axiology, or value theory, investigates the nature, types, and relationships among values. The central distinction is between intrinsic value (what is valuable for its own sake) and instrumental value (what is valuable as a means to something else). G.E. Moore argued that intrinsic value is a simple, non-natural property known by intuition; others ground it in desires, rational endorsement, or objective features of the world. Value monists (like hedonists) hold that there is one ultimate intrinsic value; value pluralists (like W.D. Ross or Isaiah Berlin) maintain that there are multiple irreducible intrinsic goods—justice, knowledge, beauty, friendship—that cannot all be reduced to a single currency. The problem of incommensurability arises when goods cannot be ranked on a single scale: is a life of artistic achievement better or worse than a life of scientific discovery, or are they simply incommensurable? This question has implications for consequentialism (which needs to compare outcomes) and for rational choice theory.

How It's Best Learned

Read Moore's Principia Ethica (chapter 1) on the naturalistic fallacy and intrinsic value, then read Christine Korsgaard's "Two Distinctions in Goodness" for a clear taxonomy. Construct examples of things that are instrumentally but not intrinsically valuable, intrinsically but not instrumentally valuable, and both. Then consider whether pleasure, knowledge, and justice are commensurable.

Common Misconceptions

• Intrinsic value does not mean "valuable regardless of context"; it means valuable for its own sake rather than as a means. Whether something has intrinsic value may still be debatable.
• Value pluralism is not the same as moral relativism; a pluralist can hold that there are objective values while maintaining that these values are irreducibly multiple and sometimes conflict.

Explainer

From your study of metaethics, you know that moral philosophy operates at two levels: the normative (what should we do?) and the metaethical (what is the nature of moral claims?). Value theory, or axiology, sits at the intersection of both. It asks: what actually makes things good? The most fundamental distinction the field draws is between intrinsic value — what is good in itself, for its own sake — and instrumental value — what is good because it leads to something else. Money has instrumental value almost universally; almost no one thinks dollar bills are intrinsically good. But what about pleasure? Knowledge? Friendship? These are candidates for intrinsic value — things whose goodness doesn't depend on what they lead to.

G.E. Moore made the question precise and difficult simultaneously. He argued that intrinsic value is a simple, non-natural property — it cannot be defined in terms of natural facts about the world. Attempts to equate "good" with natural properties like "pleasant" or "desired" commit the naturalistic fallacy: they confuse what good things happen to be like with what goodness itself is. Whatever you think of Moore's conclusion, his argument forces a choice: either intrinsic value is irreducible to natural facts (Moore's view), or we need a better naturalistic account than we've been given.

The next question is whether there is one intrinsic value or many. Value monists say one: classical hedonists say it's pleasure (or pleasure minus pain), preference utilitarians say it's satisfied preferences, Kantians ground value in rational agency. Value pluralists — following W.D. Ross or Isaiah Berlin — argue that knowledge, friendship, beauty, justice, and flourishing are each intrinsically valuable in their own right, not derivable from a single master value. Pluralism has intuitive appeal: it seems obvious that a world containing great art is better than an otherwise identical one without it, even if no one experiences the art. But pluralism raises a pressing problem — if there are multiple irreducible values, how do we choose between them?

This is the problem of incommensurability: when two goods cannot be ranked on a common scale, rational choice seems to break down. Is a life of artistic genius better than a life of scientific discovery, or are they incommensurable — neither better than the other, yet not equal? If incommensurability is real, consequentialism faces deep trouble, because it needs to compare and aggregate outcomes. Rational choice theory faces trouble too, because standard decision theory assumes all values can be quantified and traded off. Axiology thus reaches into ethics, economics, and decision theory — its questions about what has value, and how values relate to each other, constrain what any practical theory can coherently say.