Nam Nguyen wrote: > On 19/10/2013 11:54 AM, Peter Percival wrote: >> Nam Nguyen wrote: >>> On 19/10/2013 5:23 AM, Peter Percival wrote: >>>> Nam Nguyen wrote: >>>> >>>>> What definition of "invalidity" were you referring to _here_ ? Mine? >>>> >>>> If you use the word "invalidity" is newsgroups called sci.logic and >>>> sci.math then it should probably be with its usual technical >>>> meaning. If >>>> you use it in another sense you should probably say what sense that is >>>> right from the start. >>> >>> I already did in this very thread define one or two forms of invalidity >>> for meta statements. If you don't remember then say so and I'll try to >>> cite the post for you. >>> >>> In any rate, one of the forms is that: >>> >>> H => C >> >> And is => the truth-functional if-then? If not, what is it? >> >>> where it's impossible to know the truth value of H given all available >> >> And impossibility and knowing are governed by what modal and epistemic >> logics? If none, how are we to understand "impossible to know"? >> >>> definitions, permissible reasoning methods within the underlying logic >>> framework [FOL(=) in this case.] >> >> In FOL(=) there are no binary connectives that aren't truth functional, >> so I'm going to suppose that => is the truth-functional if-then. Nor >> are there any modal or epistemic operators, so I'm still in the dark >> regarding "impossible to know". > > Why don't you comment about my definition of "impossible to know" > in this context? > > (It has to do with a collection of truths in meta level).
Done elsewhere. And why don't _you_ answer my points above? One rule for Nam and another for his interlocutors (at least so Nam hopes).
-- The world will little note, nor long remember what we say here Lincoln at Gettysburg