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Show Chapter II. Reason in the Structure of the Self 58 and second, it must preserve force, or freestanding sense. For Brandom the latter determines what uttering the sentence commits one to; and this, in turn determines the former, i.e. what the utterance means (MIE 348, 353). Brandom then uses this Fregean principle of semantic invariance under substitution as a platform to launch a decompositional methodology based on the reasoning that, just as content-preserving substitution in multi-sentential inferences enables us to fix the conceptual content of single sentences, and just as content-preserving substitution in freestanding compound sentences enables us to fix the sentential content of its sentential ingredients, similarly content-preserving substitution in a simple sentence enables us to fix the content of the singular terms and predicates that are its strictly subsentential components: This same substitutional path that leads from inference to sentential conceptual content leads as well from the possession of freestanding inferential content by compound sentences to the possession of component-inferential content by embedded ingredient sentences and, … from sentential content to the content of subsentential expressions (MIE 354). …Once this sort of ingredient content has been introduced into one's semantic theory, however, it becomes available to be associated also with expressions that (unlike sentences) can occur only as parts of assertible sentences … such as singular terms and predicates, to which the concept of freestanding content does not apply (MIE 359). Following this line of reasoning, strictly subsentential categories of linguistic expression can be defined using Frege's notion of substitutional invariance: two strictly subsentential expressions are of the same grammatical category if and only if substituting one for the other preserves the sentential status of the well-formed sentence in which one of them occurs. Two strictly subsentential expressions have the same semantic content if and only if substituting one for the other preserves the "pragmatic potential" - that is, the inferential force of the sentence in which one of them occurs (MIE 368). Singular terms are then distinguished from predicates by the directionality of the substitution inferences which substitutional invariance yields. Substituting one singular term for another with the same semantic content in a sentence yields a symmetric inference from the truth of the original sentence to the truth of the sentence containing the substituted term: "Benjamin Franklin invented bifocals" is true if and only if "The first postmaster general of the United States invented bifocals" is also true. By contrast, substituting one predicate for another with the same semantic content in a sentence yields an asymmetric inference from the truth of the first to the truth of the second: If "Benjamin Franklin walked" is true, then "Benjamin Franklin moved" is also true; but not vice versa. So singular terms © Adrian Piper Research Archive Foundation Berlin |
