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G. E. Moore

Analytic · Europe · 1873 to 1958

English philosopher who defended common sense against doubt, and who held that "good" is a simple quality we see directly.

What it is

G. E. Moore (1873 to 1958) was a British philosopher who spent most of his career at Cambridge. He is known for two things, a theory of ethics in which "good" is a simple quality that cannot be defined, and a defence of common sense against philosophers who doubt that we know ordinary things.

Moore was born in London and went to Trinity College, Cambridge. The influence of J. M. E. McTaggart and Bertrand Russell drew him to philosophy. He was a fellow of Trinity from 1898 to 1904, returned to Cambridge in 1911, became editor of the journal Mind in 1921, and was a professor from 1925. At Cambridge he worked in the same years as Russell and later Wittgenstein, in a period often called a golden age of philosophy there. He was also close to the friends known as the Bloomsbury group. He died in Cambridge in 1958.

The main ideas

  • Against idealism. For a short time he was drawn to British idealism, which held that reality is at bottom mental. He soon turned against it. His paper "The Refutation of Idealism" (1903) is a famous attack on it.
  • Good cannot be defined. In Principia Ethica (1903) he argued that goodness is simple and not a natural quality like pleasure or the object of desire. Because it is simple, it cannot be broken down into parts or defined in other terms.
  • The open question. To test any proposed definition, ask whether the thing offered is really good. If we offer pleasure, it still makes sense to ask, is pleasure good? That the question stays open shows, he said, that good and pleasure are not the same.
  • The naturalistic fallacy. He gave this name to the mistake of treating good as the same as some other notion, such as pleasure or desire. He held that any definition of good in natural terms makes this mistake.
  • A defence of common sense. In 1925 he listed truisms he claimed to know for certain, such as that the earth had existed for many years. He argued that philosophers who deny such things, or deny that we can know them, are in the wrong.
  • Clear questions. Analysis played a central part in his way of working: he took narrow problems and asked exactly what a claim means before deciding whether it is true.

What it looks like in practice

Imagine someone who says that being good just means being what the majority approve of. Moore would ask her, is what the majority approves always good? If she can still wonder about that, he would say, then the two words do not mean the same thing. This is an illustration of the question he asked, not a passage from his writing.

Books and moments

  • Principia Ethica (1903) is his main work on ethics and shaped moral philosophy for decades; it also appealed to the Bloomsbury group.
  • The Refutation of Idealism (1903) is a paper against the view that the world is mind-dependent.
  • A Defence of Common Sense (1925) gathers his case for the plain things we know.
  • Editor of Mind. From 1921 he edited a leading philosophy journal.

Questions and criticism

  • How do we know good? If good cannot be defined or measured, it is fair to ask how we recognise it. Some readers describe his answer as a kind of intuitionism, in which good is known directly.
  • What does non-natural mean? It is fair to ask what Moore meant by calling good non-natural.
  • Does the open question work? It is fair to ask whether the fact that a question feels open really shows that two terms differ in meaning.

Close neighbours

The pages on Russell and Wittgenstein cover the two other Cambridge philosophers with whom he is grouped. The page on Mill covers a utilitarian thinker, for comparison on what makes things good.

Written by epchē in our own words, and checked against independent sources on 29 October 2026. The sources are listed below.

Who they connect to

Influenced

  • Ludwig Wittgenstein · Wittgenstein studied at Cambridge when Moore taught there, and later cited his defence of common sense. (scholars disagree about this link)

Other Analytic thinkers

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