G. E. Moore
1873–1958
George Edward Moore
The open question argument and the naturalistic fallacy in ethics; the defence of common sense against scepticism.
- 1873LifeBorn
- 1903EventPrincipia Ethica (1903) argues that "good" cannot be defined in terms of any natural property — pleasure, survival, what is desired.
- 1939EventIn Proof of an External World (1939) he held up one hand, then the other, and concluded that two external objects exist.
- 1958LifeDies
G. E. Moore (1873–1958) was a Cambridge philosopher who, with Bertrand Russell, broke English philosophy away from idealism and helped establish the analytic tradition. He worked by taking ordinary claims seriously and asking exactly what a philosophical thesis would require.
The naturalistic fallacy
Principia Ethica (1903) argues that "good" cannot be defined in terms of any natural property — pleasure, survival, what is desired. His test is the open question argument: for any proposed definition, asking whether the thing so defined is actually good remains a sensible question. If "good" simply meant "pleasant", asking whether pleasure is good would be as empty as asking whether a bachelor is unmarried, and it is not.
He concluded that good is simple and indefinable, known directly. The label "naturalistic fallacy" for the error of defining it otherwise passed into general use, and the argument remains a standard obstacle for naturalistic theories in ethics. It is related to, and distinct from, Hume's is-ought gap.
Defense of common sense
Moore's later work defends ordinary beliefs against philosophical arguments that contradict them. In Proof of an External World (1939) he held up one hand, then the other, and concluded that two external objects exist.
The move looks facetious and is not. His point concerns the comparison of certainties: any premise in a skeptical argument is less certain than the claim that he has hands, so the argument gives better reason to reject its premise than to accept its conclusion. This inverts the usual direction of philosophical argument and remains a live response to skepticism.
Wittgenstein spent his final notebooks, published as On Certainty, working through what Moore's proof does and does not establish.
Concept web
Open the full webQuestions
Who was G. E. Moore?
A Cambridge philosopher (1873–1958) who helped found the analytic tradition. He is known for the open question argument in ethics and for his defense of common sense against skeptical arguments.
What is the naturalistic fallacy?
Moore's name for the error of defining 'good' in terms of a natural property such as pleasure. His open question argument holds that asking whether the defining property is itself good always remains meaningful.
What is Moore's proof of an external world?
An argument that holding up one hand and then the other demonstrates that external objects exist. The point is that this claim is more certain than any premise a skeptical argument could use against it.