Moore's paradox
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G. E. Moore remarked once in a lecture on the absurdity involved in saying something like "It's raining outside but I don't believe that it is." This paradox, sometimes known as Moore's paradox, might well have been forgotten if not for the fact that Ludwig Wittgenstein is reported to have considered it to be Moore's most important contribution to philosophy.
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[edit] Elaboration
Moore himself presented the paradox in two ways.[1] The first more fundamental way of setting the problem up starts from the following three premises:
So I can say that it is raining, or instead, I can say that I do not believe that it is raining. If I say both, I am contradicting myself. But, it is perfectly possible for it to rain, and for me not to believe it. So it appears we have a peculiar situation: I can contradict myself by saying something which, in itself, is not contradictory. How can this be so?
Moore presented the problem in a second way: first, there is nothing absurd — i.e. nothing wrong — with the past-tense counterparts to Moore's sentences, e.g. Someone asserting:
Second, there is nothing absurd with the second- or third-person counterparts to Moore's sentences. For example, someone asserting:
An alternate form results by moving the negation, for instance, "Elvis is dead, but I believe that he's not." Roy Sorensen popularised the terms omissive for sentences of the form p, but I don't believe p, and commissive for sentences of the form p, but I believe not-p[2]; the terms relate to whether the sentence involves an error of omission or of commission.
In addition, many commentators hold that Moore's Paradox arises not only at the level of assertion but also at the level of belief; it is not only absurd to assert "It is raining but I don't believe it is" but also to believe it.
[edit] Commentary
Most commentators take it as a condition on a satisfactory explanation of the peculiar absurdity involved in asserting or believing Moore's sentences that it explains the contradictory-like quality of using tokens of the omissive and commissive sentence-types. It is important to emphasize that what is absurd is not, prima facie, the sentence-type but using their tokens in the way that one does when one asserts or believes them.
While in more traditional philosophical circles, Moore's Paradox has perhaps been seen as a philosophical curiosity, Moore's sentences have been used by logicians, computer scientists, and those working in the artificial intelligence community, as examples of cases in which a knowledge, belief or information system is unsuccessful in updating its knowledge/belief/information store in the light of new or novel information. [3] Philosophical interest in Moore's Paradox has recently undergone a resurgence, starting with Jaakko Hintikka,[4] continuing with Roy Sorensen,[2] David Rosenthal[5] and the impending first publication of a collection of articles devoted to the problem.[6]
[edit] Proposed Explanations
There have been several proposed constraints on a satisfactory explanation in the literature, including (though not limited to):
The first two conditions have generally been the most challenged, while the third appears to be the least controversial. Some have claimed that there is no problem in believing the content of Moore's sentences, while others hold that an explanation of the problem at the level of belief will automatically provide us with an explanation of the absurdity at the level of assertion. Some have also denied that a satisfactory explanation to the problem need be uniform in explaining both the omissive AND commissive versions.
[edit] Expansive
The most popular explanation to Moore's Paradox appeals to variations of the view that assertion implies or expresses belief in some way so that if someone asserts that p they imply or express the belief that p. On one of these views, if someone asserts p and conjoins it with the assertion (or denial) that he does not believe that p, then he has in that very act contradicted himself, for in effect what the speaker says is: I believe that p and I do not believe that p. Several versions of this expansive view ("expansive" since it replaces "p" with "I believe that p") exploit elements of speech act theory, distinguished according to the particular explanation given of the link between assertion and belief. Whatever version of this view is preferred, whether cast in terms of the Gricean intentions (see Paul Grice) or in terms of the structure of Searlean illocutionary acts (see speech act), it does not obviously apply to explaining the absurdity of the commissive version of Moore's Paradox.
[edit] Minimalizing
An alternative minimalizing view (minimalizing because it replaces the "I believe that not-p" with "not-p") often controversially attributed to Wittgenstein, is that the assertion "I believe that p" often (though not always) functions as an alternative way of asserting "p", so that the semantic content of the assertion "I believe that p" is just p: it functions as a statement about the world and not about anyone's state of mind. Accordingly what someone asserts when they assert "p and I believe that not-p" is just "p and not-p" Asserting the commissive version of Moore's sentences is thus assimilated to the more familiar (putative) impropriety of asserting a contradiction (e.g. either asserting everything or asserting nothing, depending on one's views on the content of a contradiction).
Moore's Paradox forces us to think about such diverse topics as, among other things, the relation between assertion and belief, content and expression, the nature of belief, knowledge and rationality. There is, as yet however, no generally accepted explanation to Moore's Paradox in the literature.
