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4.42 With regard to the agreement and disagreement of a proposition with the truth-possibilities of n elementary propositions there are <math>\sum_{k=0}^{K_n} \binom{K_n}{k} = L_n</math> possibilities. | 4.42 With regard to the agreement and disagreement of a proposition with the truth-possibilities of n elementary propositions there are <math>\sum_{k=0}^{K_n} \binom{K_n}{k} = L_n</math> possibilities. | ||
Agreement with the truth-possibilities can be expressed by co-ordinating with them in the schema the mark "T" (true). | |||
Absence of this mark means disagreement. | |||
4.431 The expression of the agreement and disagreement with the truth-possibilities of the elementary-propositions expresses the truth-conditions of the proposition. The proposition is the expression of its truth- conditions. | |||
(Frege has therefore quite rightly put them at the beginning, as explaining the signs of his logical symbolism. Only Frege's explanation of the truth-concept is false: if "the true" and "the false" were real objects and the arguments in ~''p'' etc., then the sense of ~''p'' would by no means be determined by Frege's determination.) | |||
4.44 The sign which arises from the co-ordination of that mark "T" with the truth-possibilities is a propositional sign. | |||
4.441 It is clear that to the complex of the signs "F" and "T" no object (or complex of objects) corresponds; any more than to horizontal and vertical lines or to brackets. There are no "logical objects". | |||
Something analogous holds of course for all signs, which express the same as the schemata of "T"and "F". | |||
4.442 Thus e.g. | |||
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is a propositional sign. | |||
(Frege's assertion sign "<math>\vdash</math>" is logically altogether meaningless; in Frege (and Russell) it only shows that these authors hold as true the propositions marked in this way. | |||
"<math>\vdash</math>" belongs therefore to the propositions no more than does the number of the proposition. A proposition cannot possibly assert of itself that it is true.) |