Re: Is Validity Just a Hypothetical or Conditional Characteristic?



galathaea wrote:

there is a class of formulas
in intuitionist predicate calculus
that are admissible but not derivable

when you say that valid arguments
" To entertain the premises of a valid argument
is already to have entertained the conclusion. "
how does this entailment associate
in these nonstandard cases?

i mean
if derivation is the application of known truth preservation rules
what does only admissible validity _mean_?


I don't know. Ask an intuitionist.

I guess that's kind of flip. Sorry.

I'm posting a sketch of my proof for classical propositional calculus.

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galathaea: prankster, fablist, magician, liar

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hz
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