|Law of the Excluded Middle: an assertion is either true or false. "There is no third possibility."See also bivalence, anti-realism, multivalued logic.|
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Sentence of the excluded middle/"not"/negation/negative sentence/representation/Millikan: thesis: the sentence of the excluded middle does not apply to simple representative negative sentences. E.g. besides the possibility that a predicate and that its opposite is true, there is the possibility that the subject of the sentence does not exist. And that is precisely the possibility that the sentence does not have a certain Fregean sense.
"P or non-p": only makes sense if "p" makes sense.
Negation: its function is never (in the context of representative sentences) to say that the sentence has no sense.
Sense/Millikan: whether a sentence has meaning, cannot be known a priori.
Negation/representation/Wittgenstein/MillikanVsWittgenstein: his error in the Tractatus, was to believe that when everyone sees that "x" in "x does not exist" has a sense, then the negative sentence is a negative representation.
Rationalism/Millikan: the rationalistic belief that one might know the difference between sense and non-sense a priori.
R. G. Millikan
Language, Thought, and Other Biological Categories: New Foundations for Realism Cambridge 1987