In article <email@example.com>, Lester Zick <DontBother@nowhere.net> wrote:
> On Sun, 23 Jul 2006 01:25:46 -0400, firstname.lastname@example.org wrote:
> >> > > >> >No. P may be false and validly imply true q. > >> > >> I don't follow this. If P is false then any Q demonstrated of P is > >> false too. > > > >Let P = Margaret Thatcher is a man, and all men are politicians. > >Let Q = Margaret Thatcher is a politician. > > > >P is false, and validly implies Q, which is true. > > Well sure but you're using compound predicates which are false to > begin with and don't really imply Q except to the extent they're > false.If I were simply to say "Margaret Thatcher is a male politician" > the effect would be exactly the same.
Not to anyone who knows anything about logic.
> The proposition is just false. Q > may or may not be true but not because P is false.
It is the compound proposition "If P then Q" whose truth is under consideration, and for the P and Q given, "If P then Q" is true.
Zick always misrepresents things when they show him wrong. This particular form of fallacious argument is more formally called the fallacy of the straw man. Zick pretends that what shows him wrong says something other that what it actually says.
Watch him do it again.
> > In the > >case of mathematical axioms, it could be argued that the axioms > >are stipulative, > > Of course they're stipulative. The difficulty is that they're assumed > true.
Not by mathematicians. Only by klutzes such as Zick.