On Thu, 20 Jul 2006 17:19:22 -0600, Virgil <firstname.lastname@example.org> wrote:
>In article <email@example.com>, > Lester Zick <DontBother@nowhere.net> wrote: > >> >> >Zick has presented no "exhaustive alternatives", he merely keeps talking >> >> >as if there were some. >> >> >> >> And Verge keeps talking as if there were none. >> > >> >I am talking as if it has not been established whether there are any, at >> >least until one has assumed something on which to base distinguishing >> >alternatives. >> >> Assumed the truth of something used to establish the truth of what is >> assumed. > >I am familiar with assuming something true in order to show that it is >actually false, but have never seen any assumption successfully used to >prove itself true.
One doesn't. One initially assumes something true and then uses its tautological alternative to show that the tautological alternative is absolutely false which proves that the initial assumptions is necessarily and universally true by inference.
I assume initially but can't prove "A" is universally true.
I then examine "not A" to see whether it's universally false. If so the universal truth of "A" is demonstrated because the tautological proposition "A, not A" is exhaustive of all possibilities for truth.
>As usual, I request an example of Zick's alleged assumption used to >prove itself true.
Well perhaps the general claim is too obscure.
>And as usual, Zick will not provide one.
See the example of the reasoning involved above. The initial assumption "A" is just an assumption and does not and cannot be used to prove itself. That should go without saying. However we can recognize the fact of self contradiction in "not A" if it is present and if present we can assume "not A" is universally false from that and infer that "A" must be universally true because its tautologically exhaustively alternative is always false.
The fact of universal self contradiction is not necessarily obvious in examples like "not A" because there is nothing apparent in the example to indicate it. But in an example like "not not" the fact of self contradiction is obvious and we infer with confidence that "not" must be absolutely and universally true because its tautological alternative "not not" is obviously and necessarily self contradictory and hence false and the tautological combination (not, "not not") exhausts all possibilities for truth.