Argument

Moore's paradox

Overview

Moore's paradox concerns the apparent absurdity involved in asserting a first-person present-tense sentence such as "It is raining, but I do not believe that it is raining" or "It is raining, but I believe that it is not raining." The first author to note this apparent absurdity was G. E. Moore. These "Moorean" sentences, as they have become known, are paradoxical in that while they appear absurd, they nevertheless

Can be true;

Are (logically) consistent; and

Are not (obviously) contradictions.

The term "Moore's paradox" is attributed to Ludwig Wittgenstein, who considered the paradox Moore's most important contribution to philosophy. Wittgenstein wrote about the paradox extensively in his later writings, which brought Moore's paradox the attention it would not have otherwise received.

Moore's paradox has been associated with many other well-known logical paradoxes, including, though not limited to, the liar paradox, the knower paradox, the unexpected hanging paradox, and the preface paradox.

There is currently not any generally accepted explanation of Moore's paradox in the philosophical literature. However, while Moore's paradox remains a philosophical curiosity, Moorean-type sentences are used by logicians, computer scientists, and those working with artificial intelligence as examples of cases in which a knowledge, belief, or information system is not modified in response to new data.

Overview adapted from Wikipedia (CC BY-SA 4.0; see the article history for authors).

Possible passages

Found by search and not yet checked by a person; they may only mention the idea in passing.

1. That gives rise to these eternal, and usually mistaken, contentions on necessity and contingency, on the possible and the impossible. But provided that it is understood that necessity and possibility, taken metaphysically and strictly, depend solely upon this question, whether the object in itself or that which is opposed to it implies contradiction or not; and that one takes into account that contingency is…

   Gottfried Wilhelm Leibniz, Theodicy Essays on the Goodness of God, the Freedom of Man and the Origin of Evil

   States what Moore's paradox is.

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2. In this case, however, the predicate and subject are not merely reversed, but one of them is changed. Instead of [A] and [B], the terms of the new proposition are [a thing which is not B], and [A]. The original proposition, Some A _is not_ B, is first changed into a proposition æquipollent with it, Some A _is_ "a thing which is not B;" and the proposition, being now no longer a particular negative, but a particular…

   John Stuart Mill, A System of Logic

   States what Moore's paradox is.

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3. This is less to be regretted because this account is completely a corollary from the nature of thinking and ideas. If the view held as to the latter is understood, the conception of truth follows as a matter of course. If it be not understood, any attempt to present the theory of truth is bound to be confusing, and the theory itself to seem arbitrary and absurd. _If_ ideas, meanings, conceptions, notions, theories…

   John Dewey, Reconstruction in Philosophy

   States what Moore's paradox is.

   Read the chapter · Open in the reader

Philosophers who discussed Moore's paradox

• G. E. Moore

Related ideas

• Belief
• Artificial intelligence
• G. E. Moore
• Jaakko Hintikka
• Ludwig Wittgenstein
• Liar paradox
• Philosophical Investigations
• Paradox
• Computer scientist
• Paul Grice
• Mind (journal)
• Speech act
• Logic
• On Certainty
• Contradiction
• Proposition
• David M. Rosenthal (philosopher)

Place in the tradition

Part of British philosophy.

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