How to Read Moore's "Proof of an External World"


  • Kevin Morris Tulane University
  • Consuelo Preti The College of New Jersey



We develop a reading of Moore’s “Proof of an External World” (PEW) that emphasizes the connections between this paper and Moore’s earlier concerns and strategies. Our reading has the benefit of explaining why the claims that Moore advances in “Proof of an External World” would have been of interest to him, and avoids attributing to him arguments that are either trivial or wildly unsuccessful. Part of the evidence for our view comes from unpublished drafts which, we believe, contain important clues concerning Moore’s aims and intent. While our approach to PEW may be classified alongside other broadly "metaphysical" readings, we believe that a proper recognition of the continuity in Moore’s philosophical concerns and strategies across his philosophical career shows that the customary distinction between "epistemological" and "metaphysical" interpretative approaches to PEW is at best superficial.

Author Biographies

Kevin Morris, Tulane University

Assistant Professor

Consuelo Preti, The College of New Jersey



Ambrose, Alice. 1942. Moore’s Proof of an External World. In Schlipp (ed.) 1942.

Ambrose, Alice and Lazerowitz, M. (eds.) 1970. G.E. Moore: Essays in Retrospect (Muirhead Library of Philosophy, ed. H.D. Lewis). London: George Allen & Unwin.

Baldwin, Thomas. 1990. G.E. Moore (Arguments of the Philosophers). London: Routledge.

Baldwin, Thomas. (ed.). 1993. G.E. Moore: Selected Writings. London: Routledge.

Baldwin, Thomas and Preti, C. 2011. G.E. Moore: Early Philosophical Writings. Cambridge, UK: Cambridge University Press.

Braithwaite, R.B. 1961. George Edward Moore 1873 – 1958. The Proceedings of the British Academy 47. Reprinted in Ambrose and Lazerowitz (eds.) 1970.

Coliva, Annalisa. 2004. “Proof of an External World”: Transmission-Failure, Begging the Question or Dialectical Ineffectiveness? Moore, Wright, and Pryor. In Wittgenstein Today. A. Coliva and E. Picardi (eds.). Padova: Il Poligrafo.

Coliva, Annalisa. 2010. Moore and Wittgenstein: Skepticism, Certainty, and Common Sense. Palgrave Macmillan.

Ducasse, C.J. 1942. Moore’s Refutation of Idealism. In Schilpp (ed.) 1942.

Ewing, A.C. 1934. Idealism: A Critical Survey. Methuen & Co.

Ewing, A.C. 1970. Moore and Metaphysics. In Ambrose and Lazerowitz 1970.

Forster, Paul. 2008. Neither Dogma Nor Common Sense: Moore’s Confidence in His ‘Proof of an External World’. British Journal for the History of Philosophy 16: 163 – 195.

Griffin, Nicholas. 1991. Russell’s Idealist Apprenticeship. Oxford: Oxford University Press.

Hicks, G. Dawes. 1904-5. Idealism and the Problem of Knowledge and Existence. Proceedings of the Aristotelian Society (new series) 5: 136 – 178.

Hylton. Peter. 1990. Russell, Idealism, and the Emergence of Analytic Philosophy. Oxford: Clarendon Press.

Klemke, E.D. 2000. A Defense of Realism: Reflections on the Metaphysics of G.E. Moore. New York: Humanities Books.

Lycan, William. 2001. Moore Against the New Skeptics. Philosophical Studies 103: 35 – 53.

Mackenzie, J.S. 1906. The New Realism and the Old Idealism. Mind (new series) 15:308 – 328.

Malcolm, Norman. 1942. Moore and Ordinary Language. In Schilpp (ed.) 1942.

Moore, G.E. 1899. The Nature of Judgment. Mind (new series) 8: 176 – 93. Reprinted in Baldwin (ed.) 1993.

Moore, G.E. 1901-02. Mr. McTaggart’s “Studies in Hegelian Cosmology”. Proceedings of the Aristotelian Society (new series) 2: 177- 214. Reprinted in Regan (ed.)1986b.

Moore, G.E. 1903a. Principia Ethica. Cambridge: Cambridge University Press.

Moore, G.E. 1903b. The Refutation of Idealism. Mind (new series) 12: 433 – 53. Reprinted in Baldwin (ed.) 1993.

Moore, G.E. 1903-04. Kant’s Idealism. Proceedings of the Aristotelian Society (new series) 4: 127-140. Reprinted in Regan (ed.) 1986b.

Moore, G.E. 1907. Mr. Joachim’s Nature of Truth. Mind (new series) 16: 229 – 35.

Moore, G.E. 1916-17. Are the Materials of Sense Affections of the Mind? Proceedings of the Aristotelian Society (new series) 17: 418 – 29.

Moore, G.E. 1917-18. The Conception of Reality. Proceedings of the Aristotelian Society 18: 101- 120.

Moore, G.E. 1918-19. Some Judgments of Perception. Proceedings of the Aristotelian Society 19: 1 – 29.

Moore, G.E. 1920-21. The Character of Cognitive Acts (Symposium with J. Laird, C.D. Broad, and G.D. Hicks). Proceedings of the Aristotelian Society (new series) 21: 132-140.

Moore, G.E. 1922. External and Internal Relations. In Philosophical Studies. London: Keegan Paul Trench Trubner & Co. Reprinted in Baldwin (ed.) 1993.

Moore, G.E. 1925. A Defense of Common Sense. Contemporary British Philosophy (second series). J.H. Muirhead (ed.). George Allen & Unwin: London. Reprinted in Baldwin (ed.) 1993. References are to the reprinted version.

Moore, G.E. 1939. Proof of an External World. Proceedings of the British Academy 25: 273 – 300. Reprinted in Baldwin (ed.) 1993. References are to the reprinted version.

Moore, G. E. 1942. A Reply to My Critics. In Schilpp (ed.) 1942.

Moore, G.E. 1959. Certainty. In Philosophical Papers. London: George Allen & Unwin. Reprinted in Baldwin (ed.) 1993.

Moore, G.E. 1953. Some Main Problems in Philosophy. London: George Allen & Unwin.

Moore, G.E. 1962. Commonplace Book 1919 – 1953. C. Lewy (ed.) London: George Allen & Unwin.

Moore, G.E. 1966. Lectures on Philosophy. C. Lewy (ed.). George Allen & Unwin: London.

Moore, G.E. 1992. Lectures on Metaphysics 1934-35. From the notes of A. Ambrose and M. Macdonald. A. Ambrose (ed). Peter Lang Publishing: New York.

Moore, G.E. Unpublished drafts of “Proof of an External World”: Cambridge University Library, Manuscripts. Add. 8875 15/3/1-6.

Nuccetelli, Susan and Seay, G. 2007a. Introduction. In Nuccetelli, S. and G. Seay (eds.) 2007b.

Nuccetelli, Susan. and Seay, G. (eds.). 2007b. Themes from G.E. Moore. In Oxford: Oxford University Press.

O’Connor, David. 1982. The Metaphysics of G.E. Moore. Dordrecht, Holland: D. Reidel Publishing.

Regan, Tom. 1986a. Introduction. In Regan (ed.) 1986b.

Regan, Tom. (ed.) 1986b. G.E. Moore: The Early Essays. Philadelphia: Temple University Press.

Russell, Bertrand. (1903) 1964. The Principles of Mathematics. London: Allen and Unwin.

Russell, Bertrand. 1959. My Philosophical Development. London: Allen and Unwin.

Russell, Bertrand. 1967. The Autobiography of Bertrand Russell, Vol. 1. London: Allen and Unwin.

Pryor, James. 2000. The Skeptic and the Dogmatist. Nous 34: 517 – 549.

Pryor, James. 2004. What’s Wrong with Moore’s Argument? Philosophical Issues 14: Epistemology: 349 – 378.

Schlipp, P.A. (ed). 1942. The Philosophy of G.E. Moore (Library of Living Philosophers, Volume IV). La Salle, IL: Open Court.

Soames, S.. 2003. Philosophical Analysis in the Twentieth Century, Volume 1: The Dawn of Analysis. Princeton: Princeton University Press.

Sosa, Ernest. 1999. How to Defeat Opposition to Moore. Philosophical Perspectives 13: Epistemology: 141 – 153.

Sosa, Ernest. 2007. Moore’s Proof. In Nuccetelli and Seay (eds.) 2007b.

Stace, W.T. 1934. The Refutation of Realism. Mind (new series) 43: 145 – 55.

Strong, C.A. 1905. Has Mr. Moore Refuted Idealism? Mind (new series) 14: 174 - 189.

Stroud, Barry. 1984. The Significance of Philosophical Skepticism. Oxford: Oxford University Press.

Warnock, G.J. 1958. English Philosophy Since 1900. London: Oxford University Press.

Wilson, Fred. 1996. Moore’s Refutation of Idealism. In Current Issues in Idealism. P. Coates and D. Hutto (eds.). Bristol: Thoemmes Press.

Wittgenstein, Ludwig. 1969. On Certainty. Trans. D. Paul and G.E.M. Anscombe. G.E.M. Anscombe and G.H. von Wright (eds). New York: Harper & Row.

Worrell, Franklin. Unpublished manuscript. Reconsidering Moore’s Realism and the Proof of an External World.

Wright, Crispin. 2002. (Anti-)Sceptics Simple and Subtle: G.E. Moore and John McDowell. Philosophy and Phenomenological Research 65: 330 – 348.