From: Virgil on
In article <45745E74.5070401(a)et.uni-magdeburg.de>,
Eckard Blumschein <blumschein(a)et.uni-magdeburg.de> wrote:

> On 12/1/2006 9:46 PM, Virgil wrote:
> > In article <456FEEEF.5070409(a)et.uni-magdeburg.de>,
> > Eckard Blumschein <blumschein(a)et.uni-magdeburg.de> wrote:
> >
> >> On 11/30/2006 1:32 PM, Bob Kolker wrote:
> >> > Eckard Blumschein wrote:
> >> >
> >> >>
> >> >>
> >> >> I consider Dedekind wrong, and he admitted to have no evidence in order
> >> >> to justify his basic idea.
> >> >
> >> > What sort of evidence? Surely not empirical evidence. Mathematics done
> >> > abstractly has no empirical content whatsoever.
> >> >
> >> > Bob Kolker
> >>
> >> Serious mathematicans have to know the pertaining confession. Dedekind
> >> wrote: "bin ausserstande irgendeinen Beweis f�r seine Richtigkeit
> >> beizubringen". In other words, he admitted being unable to furnish any
> >> mathematical proof which could substantiate his basic assumption.
> >
> > That conclusion assumes something not in evidence, that no one else has
> > been able to do what Dedekind said he had not done.
>
> Yes. It is about as impossible as to get younger.
>
>
> >> Consequently, any further conclusion does not have a sound basis.
> >> Dedekind's cuts are based on guesswork.
> >
> > So are everyone else's equally based on "guesswork", as without ASSUMING
> > something, one cannot deduce anything.
>
> The ideas by Archimedes and Aristotele, by Galilei and Spinoza, and by
> many others have proven very fruitful

in each case, they started with a system of assumptions, which, if all
those assumptions were made explicit, in mathematics would be called an
axiom system. But none of them made all their assumptions explicit.
From: Virgil on
In article <4574755B.4070507(a)et.uni-magdeburg.de>,
Eckard Blumschein <blumschein(a)et.uni-magdeburg.de> wrote:

> On 12/1/2006 4:56 PM, Tony Orlow wrote:
> > Eckard Blumschein wrote:
>
> >> In case of two finite heaps of size a and b of numbers, a=b/2 implies a<b.
> > Generalize where possible. Why is this not true in the infinite case?
>
> 2*oo is not larger than oo. Infinity is not a quantum but a quality.

Which "infinity" is that?
From: Virgil on
In article <45747E16.6020904(a)et.uni-magdeburg.de>,
Eckard Blumschein <blumschein(a)et.uni-magdeburg.de> wrote:

> On 12/1/2006 12:57 PM, Bob Kolker wrote:
> > Eckard Blumschein wrote:>
> >> Serious mathematicans have to know the pertaining confession. Dedekind
> >> wrote: "bin ausserstande irgendeinen Beweis f�r seine Richtigkeit
> >> beizubringen". In other words, he admitted being unable to furnish any
> >> mathematical proof which could substantiate his basic assumption.
> >> Consequently, any further conclusion does not have a sound basis.
> >> Dedekind's cuts are based on guesswork.
> >
> > Dedikind cuts are well defined objects which have exactly the algebraic
> > properties one wishes real numbers to have. So it is quite sensible to
> > identify the cuts with real numbers.
> >
> > We can define addition, mutliplication, subtraction and division for
> > cuts and the cuts satisfy the postulates for a an ordered field.
> > Furthermore every set of cuts (identified with real numbers) with an
> > upperbound has a least upper bound. Bingo! Just what we want.
>
> No wonder. Exactly this selfdelusion was the intention of dedekind.


Which is a great improvement on the manifold self delusions of EB.
From: David Marcus on
Eckard Blumschein wrote:
> On 11/30/2006 4:41 AM, zuhair wrote:
> > Six wrote:
>
> > and I think it was the
> > idea before Cantor showed that there can be infinite sets of different
> > sizes,
>
> He did not! Not! Not! He just misinterpreted uncountable as mor than
> countable. Is incorrect more than correct?

Are you saying that the cardinality of the reals is not greater than the
cardinality of the integers?

--
David Marcus
From: cbrown on

Lester Zick wrote:
> On 4 Dec 2006 11:29:33 -0800, cbrown(a)cbrownsystems.com wrote:
>
> >
> >Lester Zick wrote:
> >> On 3 Dec 2006 11:22:56 -0800, cbrown(a)cbrownsystems.com wrote:
> >>
> >> >Tony Orlow wrote:
> >> >> cbrown(a)cbrownsystems.com wrote:
> >> >> > Tony Orlow wrote:
> >> >> >
> >> >> > <snip>
> >> >> >
> >> >> >> Anyway, ala Leibniz, each object IS the set of properties which it
> >> >> >> possesses, so any two objects with the exact same set of properties are
> >> >> >> the same object.
> >> >> >
> >> >> > But this begs the question: what do we mean, exactly, by a SET of
> >> >> > properties? What exactly are we trying to say when we say "This set of
> >> >> > properties is the same as this other set of properties"?
> >> >> >
> >> >> > Cheers - Chas
> >> >> >
> >> >>
> >> >> Well, what we really mean is that there is a set of universal
> >> >> properties, each of which is a set of values, and that each object is
> >> >> defined by a set of values, one from each set of property values, such
> >> >> that any two distinct objects differ in at least one property value. Was
> >> >> that specific enough?
> >> >
> >> >Well, you used the term "set" four times in your above definition of
> >> >what we mean by a "set". That's why I said "this begs the question,
> >> >what do we mean, exactly, by a set of properties?".
> >> >
> >> >There's something that we intuitively seem to think of as a "set"; but
> >> >unless such a thing is carefully defined, we end up with the
> >> >contradictions of naive set theory:
> >>
> >> I think the more basic question is whether non naive sophisticated set
> >> "theory" represents all of mathematics...
> >
> >Of course it doesn't; "all of mathematics" is an extremely broad range
> >of discourse.
>
> So when mathematikers conflate mathematical ignorance with set
> "theory" ignorance they are being extremely overly broad?
>

Not all of Italian cooking involves sauteeing things in olive oil;
however it is somewhat bizzare for someone to claim to be a
knowledgeable Italian cook without knowing how to sautee things in
olive oil.

> >> and whether it has any pre
> >> emptive prerogative to the definition of terms such as "cardinality"
> >> etc. in mathematics generally?
> >>
> >
> >The reason why "cardinality" has the general definition you refer to is
> >because it is generally useful to have a term with that definition. We
> >could call it anything; but "cardinality" is the word used for this
> >term, for mostly historical reasons.
>
> Oh I don't much care what we call it. Mathematikers are the ones who
> insist definitions are only abbreviations. And I agree empirical
> utility is a cachet of modern mathematical significance. I just don't
> agree that empirical definitions are particularly true.
>

So be it then. Each to their own.

Cheers - Chas