What we mean by good › What a definition would establish

Suppose someone tells you that a good life is a pleasant life. They might be making a claim about what gives a life value, or they might be proposing a definition: by "good," they mean "pleasant." Those are different claims. We could agree about what pleasure is and still ask whether a pleasant experience is worth having.

G.E. Moore builds Principia Ethica, first published in 1903, around that distinction. He argues that goodness cannot be defined by identifying it with pleasure, desire, or another property. His argument matters because a definition can appear to settle an ethical dispute before the substantive question has been considered. Calling something pleasant supplies a description; whether its pleasantness makes it good requires an argument.

The book also asks which things have intrinsic value and how judgments about value bear on what we ought to do. Moore's answer is not exhausted by a theory of moral language. His discussions of friendship, beauty, consequences, and the value of complex wholes give content to the distinction with which he begins.

Moore distinguishes a question about the meaning or nature of goodness from a question about which things possess it. If someone asks whether pleasure is good, an answer about pleasure's value does not automatically tell us what goodness is.

A useful comparison is a definition of a triangle. Explaining a triangle as a three-sided plane figure analyzes the relevant concept through its components. Moore asks whether goodness permits an analysis of this kind. His answer is that it does not: goodness is simple rather than composed of more elementary concepts (Principia Ethica, sections 6–8).

His comparison with yellow is meant to clarify simplicity. Someone who understands yellow can recognize what we are referring to, although listing its conceptual parts will not explain it as the definition of a triangle explains a triangle. Moore thinks goodness is similarly resistant to analysis. The comparison concerns their being simple notions; it does not make goodness a color or a property detected by eyesight.

This leaves room for several kinds of explanation. We can give examples, distinguish goodness from neighboring ideas, and discuss the circumstances in which something is good. What Moore denies is that these explanations amount to an analysis of goodness into something else. Indefinability therefore does not mean that ethical discussion has to stop.