Bloomsbury Encyclopedia of Philosophers - Moore, George Edward (1873–1958)
The Dictionary of Twentieth-Century British Philosophers


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Moore, George Edward (1873–1958)

Moore, George Edward (1873–1958)
DOI: 10.5040/9781350052437-0294

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G.E. Moore was born in the London suburb Upper Norwood on 4 November 1873 and died in Cambridge on 24 October 1958. He was the son of Daniel Moore, MD and Henrietta Sturge. Daniel Moore worked as a doctor until he devoted himself full-time to the education of his eight children. In 1892 Moore began his undergraduate studies at Trinity College, Cambridge, focusing primarily on classical literature. It was during his first year there that he met Bertrand Russell . At Russell’s encouragement, Moore turned his attention to philosophy. As young students, Russell and Moore were both admirers of absolute idealism, then championed most prominently by the philosophers John McTaggart – at Cambridge, a teacher of Moore – and the Oxford Professor F.H. Bradley . Following his undergraduate studies, Moore applied for, and on his second attempt was awarded, a fellowship at Trinity. During the two years prior to his fellowship, Moore had begun to turn away from idealism in favour of what we might call his ‘Common Sense Realism’. As a fellow of Trinity, Moore gave his first lectures on ethics at the Passmore Edwards Settlement in London and completed his first book and most wellknown work, Principia ethica, in 1903. When his fellowship ended after six years, Moore spent approximately three and a half years in Edinburgh with his close friend, Alfred R. Ainsworth, before moving to London with two of his sisters. During this time, he did not take up academic duties. In 1911 Cambridge offered Moore a lectureship in moral sciences. He began teaching courses on philosophical psychology, and in 1925, succeeded James Ward as Professor of Mental Philosophy and Logic, a position Moore held until 1939. During World War II, at the urging of close friends and colleagues, Moore travelled to the United States, giving lectures and teaching courses at various institutions; in 1944 he returned to England. During his professorship at Cambridge, Moore succeeded G.F. Stout as the editor of the journal Mind, and held that position from 1921 to 1947. In 1951 he was appointed to the Order of Merit. Moore died in Cambridge in 1958.

Within the professional discipline of academic philosophy, Moore was among the most influential British philosophers of the early twentieth century. He is well known for his contributions to ethics and the theory of knowledge. His emphasis on common sense and the analytic method in attempting to solve philosophical problems exerted a substantial influence on the general character of what is now one of the most prominent traditions in academic philosophy: the analytic, or Anglo-American, tradition. He was closely associated with, and exerted not a little in the way of influence on, some other members of this elite group, most notably Bertrand Russell, Ludwig Wittgenstein and F.P. Ramsey . Outside professional academic philosophy, Moore exerted an important influence on the Bloomsbury Group, who based many principles they held in common somewhat loosely on Moore’s ethical philosophy. It is frequently held that the actual details of Moore’s philosophy were much less influential on the Bloomsbury Group than were the strength and charisma of his character.

Moore was interested in a wide range of philosophical topics, most notably, the nature of goodness, the integrity of our knowledge of the external world, and the right way to conduct philosophical inquiry. In an illuminating remark, Moore explains what drew him to philosophical reflection: ‘I do not think that the world or the sciences would ever have suggested to me any philosophical problems. What has suggested philosophical problems to me is things which other philosophers have said about the world or the sciences’ (Levy, p. 14).

Not surprisingly, Moore characterized his approach to philosophical issues as a commitment to common sense. Here, Moore suggests that there is a stock of commonly held propositions – things that most rational agents know – that provide the background against which we perform both our ordinary and our philosophical reflections. Examples of such propositions include ‘there now exists a living human body’, ‘there are many living humans populating the earth’, ‘at some point in the past, this human (me) was born’, ‘this human has, at various times, occupied different locations relative to the other things populating the earth’, and so on. These sorts of proposition, Moore thinks, cannot be seriously disputed. While he does not claim that it is necessarily incoherent to deny such propositions (and their implications), he does suggest that most philosophical discussions are implicitly premised on the truth of these background ‘common sense’ claims.

Moore is especially influential as a paradigm for what became the characteristic ‘method’ of Anglo-American philosophical inquiry: conceptual analysis, or what was sometimes referred to as ‘ordinary language philosophy’. Basically, the strategy is to defend philosophical claims by careful attention to our conceptual intuitions. These intuitions are revealed to us by attending, in turn, to our instincts about when terms are appropriately applied in particular cases (imaginary or real). For example, Moore defends the claim that we in fact employ distinct concepts of certainty. He accomplishes this by noticing that what we mean when we use the term differs depending on how we use it. Compare the expressions ‘it is certain that p’ and ‘I feel certain that p’. While it is logically possible that both I feel certain that p and p be false, it makes no sense to suppose that p could be false if it is certain that p. Hence, the term ‘certain’ in the two sentences above clearly picks out a distinct concept in each case.

In the area of epistemology, or the theory of knowledge, Moore is concerned to defend the closely related claims that we do in fact have knowledge of the external world and that when we know something, we are in fact certain that it is true. In keeping with his common sense approach, Moore famously addressed sceptical challenges to the existence of the external world. Descartes, for example, had raised the threat of scepticism in his Meditations when he pointed out that how things appear to us in our perception of the external world is equally consistent with both the possibility that those perceptions correctly represent the world, and the possibility that, as a result of a radical deception by a malevolent, all-powerful, demon, we are completely mistaken about the character and existence of the external world. More recently, the same point is made by entertaining the possibility that I might actually be a disembodied brain in a vat, hooked up to a supercomputer aimed at constructing an illusion of an external world. Sceptical hypotheses of this sort seem to make it impossible to have any knowledge about the external world. Since my perception of the world around me is equally consistent with both the actual existence of that world and the deceptive supercomputer, I cannot be certain that I am not a brain in a vat. Yet if I do not know whether I am a brain in a vat, then clearly I cannot be certain of the ordinary things perception tells me – such as, ‘I have two hands’ or ‘I am sitting at my desk typing’.

Moore turns the sceptical argument on its head. He offers what he calls a ‘proof’ of the external world, one that is aimed at ensuring our knowledge and certainty of its character and existence. We might summarize Moore’s proof as follows: ‘Here is one hand. Here is another. Hence, there are two human hands. Hence, external things do in fact exist.’ Moore’s proof gives us reason to reject the premise with which the sceptic begins, since it follows, a fortiori, from the various conclusions of this type of argument that I am not a brain in vat. And so we have before us two types of proof, Moore’s and the sceptic’s. Moore’s next step is to give reasons for thinking that his proof of the external world better meets the criteria for what makes a proof satisfactory. Among other things, a good proof must be such that it takes us from more obvious premises to a less obvious conclusion. In this respect, Moore’s proof has an apparent advantage over the sceptics; for, after all, what could be more obvious than the premises ‘here is one hand’ and ‘here is another’? Moreover, Moore insists that he is not required to give a further proof of these premises, just as the sceptic is not required to give a proof of his premises (and in turn proofs for the premises of that proof, and so on). The buck stops somewhere, and for Moore, ‘here is one hand’ is an excellent place to stop.

Next, in opposition to what is presently the received view, Moore claims that knowing that p implies being certain that p is true. Moore’s argument for this thesis appears to rely primarily on linguistic facts about the contexts of our utterances. At present, I am in a sitting position, typing. This, it appears, is something I know to be true. Moore suggests that in ordinary circumstances, it would not make sense to claim that I know that I am now in a sitting position (and not standing) and yet also claim that I cannot be certain that I am sitting. If the evidence of my senses confirms that I am sitting (and not standing), then it would be a mistake for me, in those circumstances, to deny that it is certain. Finally, Moore holds that we can be certain that a proposition is true even if that proposition is contingent – that is, even if it might have been the case that the proposition was false.

Two points are important here. First, in places, Moore seems to be thinking of the expression ‘the evidence of my senses confirming that p’ as a success concept. In other words, if the evidence of my senses confirms a proposition, then that proposition is true. The evidence of my senses confirming the truth of some proposition p must therefore be distinguished from it appearing as though p is true. Second, Moore distinguishes between different orders of knowledge. Specifically, while I may know that p, it need not follow necessarily from that fact that I know that I know that p. In short, higher-order levels of knowledge are not implied by the possession of first-order knowledge. This is important, since philosophers are apt to argue against the possibility of knowledge of the external world by showing that we cannot confirm that I know what I think I know. Moore suggests that this is a mistake since one might know that he is not dreaming even though he can’t prove that he’s not (and thus, know that he knows he’s not dreaming).

Moore’s magnus opus is the Principia ethica, in which he takes up questions concerning how we should properly understand our ethical, or ‘normative’, concepts, in particular the concept ‘good’. In the course of his investigation, Moore offers some of his most important insights, describing the ‘naturalistic fallacy’ and the ‘open question’ argument.

The naturalistic fallacy is the mistake of interpreting attributive claims about moral values as definitions of those values. (And, as the name of the fallacy suggest, these abortive attempts at definitions typically happen to involve natural properties as the defining terms.) Moore held that the naturalistic fallacy was common in ethical theorizing and his discussion is an attempt to warn us away from this mistake. We can make Moore’s discussion of this fallacy clearer as follows. Start by noticing two important distinctions – the distinction between (1) attributions and definitions, and (2) between complex and simple concepts. Compare the following two sentences:

‘Daisies are yellow.’

‘Triangles are three-sided figures, the sum of the interior angles of which is 180°.’

These sentences differ importantly, despite some grammatical similarities. The first sentence merely attributes a property to its subject – it tells us that, among the many things that daisies are and might be, they are yellow. The second sentence purports to give a definition or analysis of the concept ‘triangle’ – it tells us what the term ‘triangle’ means. It is easy to see that it would be a terrible confusion to suppose that the first sentence was giving a definition rather than merely attributing a property, for that would imply that the person uttering the sentences is suggesting that the correct definition of the property of being a daisy is the properly of being yellow. That claim would be clearly false – ‘being a daisy’ just does not mean ‘being yellow’, even though daisies are in fact yellow.

Next, Moore distinguishes between complex and simple properties. If it is possible to analyse a property, then the property is complex. On the other hand, Moore claims that some concepts are simple: they are indefinable or unanalysable. This is not to say that one could not give a lexical definition of a simple concept – it is always possible, in other words, to say something in aid of helping one arrive at the correct understanding to a term; this is, after all, the job of a dictionary. Moore’s claim, rather, is that in the case of simple concepts, even the best lexical definition fails to be a complete analysis of the concept: the definition, while pushing one towards an understanding of the concept, does not exhaustively capture the meaning of the concept as a complex of other concepts. The meaning is rather grasped by the understanding as a simple whole. Take, for example, the concept of ‘triangle’ and the concept ‘yellow’ (the latter is an example borrowed from Moore). ‘Triangle’, as we have already seen, is a complex concept – the meaning of the term is exhaustively described by a complex string of further concepts, which include the ideas of a figure, an angle and a sum. The meaning of the term ‘yellow’, Moore claims, is simple – there are no further concepts that make up the meaning of ‘yellow’. If a person understands what it means for something to be yellow, then the idea of ‘yellow’ is grasped by that individual as a simple whole.

Applying these insights to ethical matters, Moore insists that the concept ‘good’ is a simple concept. Thus, no sentence purporting to give an analysis of ‘good’ could possibly be correct; since ‘good’ is simple and indefinable. Despite this fact, many philosophers have unhappily treated some of the attributive claims they defend concerning the concept ‘good’ as definitions of that concept. Moore explains that these claims, while perhaps true under a different interpretation, cannot be definitions. Thus, the naturalistic fallacy involves interpreting such claims as definitions when they are in fact mere attributions. In other words, it is the mistake of confusing claims involving ‘good’ that attribute this property with claims that define the property. Moore gives the following example to demonstrate his point. Suppose I hold that pleasure is good. If my claim here is that good is properly defined as pleasure – that good is actually nothing more than pleasure and that ‘good’ merely means ‘pleasure’ – then I fall prey to the naturalistic fallacy. The claim ‘pleasure is good’ could never correctly mean that good really just boils entirely down to pleasure, even if it is nevertheless a fact that both pleasure is always good and is the only thing that is good. In other words, even if pleasure turns out to be the only intrinsically good thing in the universe, it would still be a mistake to infer that ‘good’ merely means ‘pleasure’. To think otherwise is to commit the naturalistic fallacy.

(Finally, it is worth noting that Moore calls the fallacy ‘the naturalistic fallacy’ because it mistakenly attempts to define good as a natural thing – as, say, pleasure – and in doing so, attempts to analyse a non-natural property specifically, an evaluative or normative property – in terms of the natural world. This feature of Moore’s discussion, however, should not obscure the fact that the central mistake of the fallacy is to suppose that ‘good’, as a simple property, could be analysed: see ‘The Refutation of Idealism’, p. 65.)

Turning now to Moore’s ‘open question’ argument, we see him attempting to argue for his premise that the concept ‘good’ is in fact simple and indefinable. Moore claims that for any possible proposed definition of ‘good’, it is intelligible to ask whether the analysing properties proposed by the definition really are, in fact, good. For example, if I try to define good as pleasure, I am still faced with the fact that it is very much an open question whether pleasure is good. The fact that one’s understanding continues to be faced by the open question shows that the concepts involved in the purported definition are distinct from each other, distinct in the understanding. Thus, in the case of pleasure, while it may turn out that ‘pleasure is not good’ is false, it is nevertheless an intelligible question, since the concepts ‘good’ and ‘pleasure’ are not the same. And since, in the case of the concept ‘good’, there are no concepts that, by themselves or taken as a group, are immune to the open question, good must be indefinable.

Ultimately, Moore held that our understanding of the concept ‘good’ is direct and intuitive. Moreover, Moore’s own contribution to the basic task of ethical theory – that is, the task of making interesting generalizations about ethic properties such as ‘good’ and ‘right’ – includes his claim that there are only two things that are intrinsically good: friendship and the pleasure we experience in our contemplation of the beautiful.


Prindpia ethica (Cambridge, 1903; rev. edn, 1993).

‘The Refutation of Idealism’, Mind, vol. 12 (1903), pp. 433–53 ; repr. in Philosophical Studies.

‘Kant’s Idealism’, Proceedings of the Aristotelian Society, vol. 4 (1903–1904), pp. 127–40 ; repr. in Philosophical Studies.

‘The Nature and Reality of Objects of Perception’, Proceedings of the Aristotelian Society, vol. 6 (1905–1906), pp. 68–127 ; repr. in Philosophical Studies.

‘The Subject-Matter of Psychology’, Proceedings of the Aristotelian Society, vol. 10 (1909–10), pp. 36–62 .

Ethics (New York and London, 1912).

‘The Conception of Reality’, Proceedings of the Aristotelian Society, vol. 18 (1917–18), pp. 101–20 ; repr. in Philosophical Studies.

‘Some Judgments of Perception’, Proceedings of the Aristotelian Society, vol. 19 (1918–19), pp. 1–29 ; repr. in Philosophical Studies.

‘External and Internal Relations’, Proceedings of the Aristotelian Society, vol. 20 (1919–20), pp. 40–62 ; repr. in Philosophical Studies.

Philosophical Studies (New York and London, 1922).

‘A Defence of Common Sense’, Contemporary British Philosophy, edited by J.H. Muirhead (1925), pp. 193–223 ; repr. in Philosophical Studies.

‘Proof of an External World’, Proceedings of the British Academy, vol. 25 (1939), pp. 272–300 ; repr. in Philosophical Studies.

‘An Autobiography’, in Schilpp (ed.), The Philosophy of G. E. Moore, pp. 3–39 .

‘A Reply to My Critics’, in Schilpp (ed.), The Philosophy of G. E. Moore, pp. 535–677 .

Some Main Problems of Philosophy (New York and London, 1953).

Philosophical Papers (New York, 1959).

Elements of Ethics , ed. Tom Regan (Philadelphia, 1991).

Further Reading

Levy, Paul, Moore: G. E. Moore and the Cambridge Apostles (New York, 1979).

Schilpp, Arthur (ed.), The Philosophy of G. E. Moore (Chicago, 1942).

Soames, Scott, Philosophical Analysis in the Twentieth Century , vol. 1, The Dawn of Analysis (Princeton and Oxford, 2003).

Stroll, Avrum, Moore and Wittgenstein on Certainty (New York and Oxford, 1994).