"However unwillingly a person who has a strong opinion may admit the possibility that his opinion may be false, he ought to be moved by the consideration that, however true it may be, if it is not fully, frequently, and fearlessly discussed, it will be held as a dead dogma, not a living truth."

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The trouble is that the expression 'material thing' is functioning already, from the very beginning, simply as a foil for 'sense-datum'; it is not here given, and is never given, any other role to play, and apart from this consideration it would surely never have occurred to anybody to try to represent as some single kind of things the things which the ordinary man says that he 'perceives.

— J. L. Austin