[FOM] Post Completeness and Conservative Extensions

Harry Deutsch hdeutsch at ilstu.edu
Mon Apr 7 21:57:59 EDT 2014

Doesn't it follow from the fact that classical propositional logic is 
Post complete--meaning that no non-theorem in the language of classical 
PC can be added consistently--that any consistent extension of classical 
PC (classical quantification theory, for example) is conservative over 
PC?  Is this known, say, in the exercises in logic books?


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