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The big question: how long is a piece of string theory? (can we ever understand the universe?)
Sydney Morning Herald ^ | February 25, 2004

Posted on 02/24/2004 6:38:39 AM PST by dead

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Comment #21 Removed by Moderator

To: onmyfeet
I suspect a statement that is undecidable by basic mathematics would be incomprehensible to most -- probably including me.

"There is a set of numbers 'smaller' than the reals and 'bigger' than the natural numbers" (aka the Continuum Hypothesis) is undecidable but is easily grasped by most with a short explanation of what 'bigger' and 'smaller' mean in this context.

22 posted on 02/24/2004 8:52:44 AM PST by edsheppa
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Comment #23 Removed by Moderator

To: dead
There is a lot of math that describes nothing in nature. Who says math describes the universe?
24 posted on 02/24/2004 9:16:34 AM PST by RightWhale (Theorems link concepts; proofs establish links)
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To: longshadow
Gödel showed that there will exist some statements derivable in a mathematical system which can't be decided based on the axioms of that system.

There is an important assumption that is often overlooked: the methods of proof in the system must be "finitistic." IOW if you allow something like transfinite induction then you can prove completeness and consistency.

Of course then the question is, is a method like transfinite induction intuitively obvious?

25 posted on 02/24/2004 9:17:30 AM PST by edsheppa
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To: Physicist
I do disagree with Davies, however, that Gödel's theorem has anything to do with physics.

It seems intuitively clear to me if you make the assumption that people (i.e. beings capable of formulating number theory) are a natural consequence of physical law.

I'll grant you what's not clear is whether the incompleteness theorem has anything interesting to do with physics.

26 posted on 02/24/2004 9:26:45 AM PST by edsheppa
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To: onmyfeet
A little hairy for me

Actually section 1 (esp. 1.1) of that page is pretty short and easy-to-read and the rest is not material to understanding CH.

27 posted on 02/24/2004 9:43:11 AM PST by edsheppa
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To: old-ager
I'm not PH, and so I can't claim to speak for him, but I believe that it's because the Evolution pings are for more than just crevo threads. Discussions of scientific discoveries of this nature are also typically of interest to those on the Evolution ping list.
28 posted on 02/24/2004 10:35:30 AM PST by Dimensio (I gave you LIFE! I -- AAAAAAAAH!)
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To: edsheppa
It seems intuitively clear to me if you make the assumption that people (i.e. beings capable of formulating number theory) are a natural consequence of physical law.

It's not clear to me at all. Number systems, formal as they are, were arrived at via human reasoning, which is not a formal system. Human reasoning is, I maintain, complete, in that all possible truths are in principle available to it, including the truth or falisity of formally undecidable Gödel statements. The price paid for this is inconsistency: some wrong statements will seem to be true, and vice-versa. I don't think I need to make a case that human reasoning is inconsistent.

29 posted on 02/24/2004 11:07:56 AM PST by Physicist
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To: Dimensio
Thanks Dimensio. I appreciate your response.
30 posted on 02/24/2004 11:35:51 AM PST by old-ager
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To: longshadow
What is the 'precision of the axioms'? Oh forget it! my head is spinning also.
31 posted on 02/24/2004 11:41:53 AM PST by Eighth Square (All the people, all of the time!)
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To: Eighth Square
What is the 'precision of the axioms'?

Nothing more than the fact that the precise mathematical statement of the axioms gives a rigorous definition of a topological space. The moment one tries to water that down to a layman-level understanding, one sacrifices rigor (or "precision") for understandability.

Sorry about the headache....

32 posted on 02/24/2004 2:44:19 PM PST by longshadow
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To: edsheppa; Doctor Stochastic
"There is a set of numbers 'smaller' than the reals and 'bigger' than the natural numbers" (aka the Continuum Hypothesis) is undecidable....."

Caution must be execised to avoid confusing "undecided" hypotheses from "undecideable" hypotheses; the CH is undecided -- that is, we don't know if it is true or not, and it also makes no difference to standard set theory whether it is true or false (IOW, standard set theory is independent of the CH), but no one to my knowledge has demonstrated the CH can NEVER be decided. IOW, no one has shown the CH is a Gödel statement.

33 posted on 02/24/2004 3:13:44 PM PST by longshadow
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To: Physicist
"Any given mathematical statement (eg, 11 is a prime number) must either be true or false, right? Wrong!"

IMO, this is a very, very horrible way to get the idea across. For starters, it's flat out false. It makes the claim in an even more positive fashion than I put it, and is just going to end up confusing a lot of people, despite his rather insufficient attempt later to correct himself. I do agree with everything else you've said, Physicist -- no argument there -- but I guess I just don't think it's a good idea to make false statments, as he's done here. It only adds to the confusion, skepticism and ignorance. We can almost guarantee there are going to be people running around after reading this article claiming that math is a joke, very likely including NEA types who think there are no "right" answers anyway.

34 posted on 02/24/2004 3:53:07 PM PST by LibWhacker
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To: LibWhacker
Indeed, well written. Clear and concise.
35 posted on 02/24/2004 4:09:47 PM PST by MHGinTN (If you can read this, you've had life support from someone. Promote life support for others.)
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I use the 'flatland story', personally, when asked to explain manifolds.
36 posted on 02/24/2004 4:10:36 PM PST by MHGinTN (If you can read this, you've had life support from someone. Promote life support for others.)
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To: longshadow
Thanx!
37 posted on 02/24/2004 4:40:57 PM PST by Eighth Square (All the people, all of the time!)
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To: Eighth Square
Thanx!

You're most welcome. But I hope you were talking notes, because there will be a "pop" quiz next period!

;-)

38 posted on 02/24/2004 4:59:14 PM PST by longshadow
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To: longshadow
talking , er "taking"
39 posted on 02/24/2004 5:00:40 PM PST by longshadow
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To: LibWhacker
For starters, it's flat out false.

I think you're misreading it, but let's be explicit: what is wrong about that statement, in your reading?

40 posted on 02/24/2004 5:05:19 PM PST by Physicist
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