Talk:No-go theorem

Uncertainty and incompleteness
Both theorems are among the strongest in science and mathematics. How did they end up in here? 93.173.147.108 (talk) 06:23, 8 April 2009 (UTC)


 * The Heisenberg uncertainty theorem and Godel's incompleteness theorem are both good examples of no-go theorems, by the definition given on the page. They are results which prove that something is impossible - which is exactly what a no-go theorem is. The other theorems, which you didn't object to, are also similar - well-understood and strongly proven results that prove that something is impossible. -dmmaus (talk) 00:28, 9 April 2009 (UTC)
 * The problem is that the terminology is not used in mathematics. The extension to mathematics appears to be original research by WP standards (which of course is completely different from being either "original" or "research" in ordinary usage). --Trovatore (talk) 02:12, 9 April 2009 (UTC)
 * Ah, fair enough to remove Arrow's and Godel's then. But Heisenberg is definitely physics and a good example. -dmmaus (talk) 07:26, 9 April 2009 (UTC)

Heisenberg's uncertainty principle is never called a no-go theorem. To qualify as a no-go theorem, it should satisfy two criteria: 1) It should be a theorem. That is it must be a precisely stated and nonobvious mathematical result following from a reasonably rigorous proof. This should be contrasted with a physical insight or the result of some calculation. 2) The theorem must prove that some theoretical construction which was widely believed, or at least reasonably speculated, to be possible is in fact not possible. Both of these criteria could apply to results in mathematics, but as far as I know the term is only widely used in theoretical physics. I'm not sure who coined the term, but I would not be surprised if it was Sidney Coleman. Would be interested to find out. — Preceding unsigned comment added by 157.82.60.173 (talk) 14:52, 8 March 2013 (UTC)

Notable?
I'm not sure this page meets WP:NOTABLE. It has been flagged for additional cites for the last 5 years, and it's not clear the existing two sources even refer to the concept of no-go theorems at all. I don't have access to them but I suspect they may be being used merely as references to Bells etc in QM, and not specifically to Bells as a no-go theorem. The above discussion on Uncertainty and Incompleteness reflects the problem. One IP user comments that Heisenberg "is never called a no-go theorem", and gives two precise criteria for something being no-go. However, if those are source-able assertions surely they should be in the main article, along with their sources? The same user speculates that the term was coined by Sidney Coleman, but acknowledges that it is only speculation. Again, shouldn't we expect to have that kind of info in the article itself, and with a WP:RS? Like many, I am well aware of the notion of the no-go theorem, and would quickly cite Bell as an example. But is that any more than tribal knowledge for the time being; does it merit being in WP yet? If the answer is, it does, then we need not just more citations, we need *any* cites (since as I say, I doubt the two already there are actually there in support of the no-go theorem concept itself). Sleety Dribble (talk) 01:49, 7 April 2017 (UTC)
 * Actually, a quick Google shows plenty of non-WP uses of the term, so I think we're good on the notability side of things. We just need to fix the WP:RS problem. I'm half inclined to remove the two existing cites, so we can upgrade the current to a full-blown  . A mere  is masking the extent of the problem I think. In fact, at very least I'm going to add a  (that usually requires the sources to be checked, but I have no access to them and I'm fairly sure, from their titles and dates, that they're providing support only for the QM concepts being mentioned, not the no-go theorem concept specifically). Sleety Dribble (talk) 02:02, 7 April 2017 (UTC)
 * I'm sorry, but what do you mean when you write "it's not clear the existing two sources even refer to the concept of no-go theorems at all"? – Tea2min (talk) 06:51, 7 April 2017 (UTC)
 * Sorry, after reading what you wrote again I see that it actually is clear what you mean when you write "it's not clear the existing two sources even refer to the concept of no-go theorems at all". The two sources strictly discuss the no-go theorems that rule out certain hidden-variables interpretations of quantum mechanics. (Chapter 2 of Bub's "Interpreting the Quantum World" is titled "Bell's 'no go' theorem", chapter 3 is ""The Kochen and Specker 'no go' theorem". I don't have access to Holevo's "Probabilistic and Statistical Aspects of Quantum Theory" anymore.) So, yes, you are right, the article really does not provide any sources that would discuss the term "no-go theorem" as it is more generally used by the theoretical physics community. – Tea2min (talk) 08:45, 7 April 2017 (UTC)

remember...
no-go today, is go tomorrow :) 88.108.241.37 (talk) 15:42, 17 June 2017 (UTC)