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Topic:
How do you prove that 2+2=4? Is it enough to consider 2 objects,
then 2 more then put them together and count them and get 4, or do you have
to resort to fancy-schmancy methods?
Replies:
8
Last Post:
Nov 18, 2012 7:45 PM
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Re: How do you prove that 2+2=4? Is it enough to consider 2 objects, then 2 more then put them together and count them and get 4, or do you have to resort to fancy-schmancy methods?
Posted:
Nov 16, 2012 12:33 AM
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In article
<17eeb626-2a35-4177-ad68-92cf18be577b@c16g2000yqe.googlegroups.com>,
Charlie-Boo <shymathguy@gmail.com> wrote:
> On Nov 15, 11:22 pm, donstockba...@hotmail.com wrote:
> > Just askin.
>
> Principia Mathematica BS says it takes 100 pages. I don't know
> anybody who has tried to explain what is going on there (everyone just
> sits in awe at the number of pages), but Peano Arithmetic proves it in
> a few steps where 2 is 0'' and 4 is 0'''', based on the axioms x+0=x
> and x+y' = (x+y)' where x' is x+1 ("successor of x").
>
> C-B
You can view "Prinicpia Mathematica" at the link:
http://archive.org/stream/PrincipiaMathematicaVolumeI/WhiteheadRussell-Pr
incipiaMathematicaVolumeI#page/n95/mode/2up
More is being done than just proving that "2+2=4". For example, logical
propositions like "q implies (p implies q)" are being proved.
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