[FOM] Re: consistency and completeness in natural language

[Torkel Franzen]

Hartley Slater says:

  >Trivially, and vacuously, one can replace the used 
  >sentence, P, on the right-hand side of a reflection principle, with 
  >TP, where 'T' is a truth operator (i.e. the null or identity operator 
  >in the modal system T), but my interest starts from the recognition 
  >that the reflection principles Tennant is concerned with have 
  >abandoned entirely any truth-predicate. 

  To be sure, the reflection principle does not use any truth predicate,
but neither does "S is consistent", and since "if S is consistent then G"
is provable in S itself, any "need" for a truth predicate to convince
ourselves of the truth of G would appear only in establishing the
reflection principle, or in establishing "S is consistent". What,
specifically, in Tennant's paper do you find clarifying as regards
such a possible need for a truth predicate? You have in mind, perhaps,
his discussion of "showing" vs "saying", and of prosentential
interpretations, on p 574f?

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Torkel Franzén, Luleå University of Technology