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==Article for deletion? ==
I dunno, this article just sounds plain old confused and wrong to me; I'm tempted to suggest deletion. Arguing that a hung gate is a form of quantum indeterminacy is certainly a novel idea, but I think a whole lotta work would need to be done to prove this, in particular, ruling out purely classical explanations like [[ground bounce]] and what not. I doubt that anyone who actually designs real transistors for a living would agree with such an assessment. I'd need to see something other than handwaving to believe this. [[User:Linas|linas]] 04:19, 16 September 2005 (UTC)
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This is indeed curious. First of all the above abstract talks about synchronizers instead of arbiters. Does the article explain the difference? Not much confusion exists about the practical importance of metastability for arbiters. Conventional arbiters unavoidably show metastable behavior in principle and also in practice, if properly designed. The metastability of properly designed arbiters has been measured and well qualified many times in the literature. Is this article informed about the literature? Has anyone ever cited this article? Thanks,--[[User:CarlHewitt|Carl Hewitt]] 21:09, 4 October 2005 (UTC)
Indeterminacy seems to be suggested by Godel's proof that mathematical systems cannot prove themselves. This occurs in practice where diagnosis of a failing machine is extremely difficult without an external system of test intruments. And the nature of information being entropy, a purely statistical measure, suggests that one of the reasons computer software fails particularly when it is very large programs, is that the meaning of one bit in the context of the whole must be close to perfectly consistent with the whole when the whole system exists in a thermodynamic environment in which entropy is also an important measure. Seems best to leave the article simply described as controversial. <small>—The preceding [[Wikipedia:Sign your posts on talk pages|unsigned]] comment was added by [[User:67.136.147.134|67.136.147.134]] ([[User talk:67.136.147.134|talk]] • [[Special:Contributions/67.136.147.134|contribs]]) 04:41, 1 July, 2006 (UTC{{{3|}}})</small>
==POV label==
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:::::::Thanks for your comments. I have further clarified the article. Please see what you think. Thanks,--[[User:CarlHewitt|Carl Hewitt]] 23:07, 6 December 2005 (UTC)
== Kinds of indeterminacy ==
Quantum indeterminacy is usually mentioned when one is concerned with the predictability or nonpredictability of events. For example, predictability explicitly arises in the earlier physical theory now known as [[classical mechanics]], which lead to a philosophical position of [[Scientific determinism]]. Some philosophers have tried to identify the basic types of indeterminacy that underly the inability of humans to predict the future. Four types of indeterminacy are:
* quantum indeterminacy, built into the structure of physical reality.
* indeterminacy due to chaos as described in [[chaos theory]] ("Sensitive dependence on initial conditions").
* indeterminacy caused by limited powers of [[observation]] and integration of the facts.
* limitations due to the nature of human [[memory]] and thought processes. <small>—''The preceding [[Wikipedia:Sign your posts on talk pages|unsigned]] comment was added by'' [[User:24.23.213.158|24.23.213.158]] ([[User talk:24.23.213.158|talk]] • [[Special:Contributions/24.23.213.158|contribs]]) 22:36, 28 February 2006 (UTC{{{3|}}})</small><!--Inserted with Template:Unsigned2-->
:I'm not sure what you're referring to, but my assertion is that the system described is not predictable because of external inputs, not because of "quantum indeterminacy", or any other kind of indeterminacy. [[User:Arthur Rubin|Arthur Rubin]] | [[User_talk:Arthur_Rubin|(talk)]] 02:24, 1 March 2006 (UTC)
::The consensus in the scientific literature is that outcome of the operation of an Arbiter is indeterminate once it has become metastable. Do you know of any literature to the contrary? <small>—''The preceding [[Wikipedia:Sign your posts on talk pages|unsigned]] comment was added by'' [[User:24.23.213.158|24.23.213.158]] ([[User talk:24.23.213.158|talk]] • [[Special:Contributions/24.23.213.158|contribs]]) 05:22, 1 March 2006 (UTC{{{3|}}})</small><!--Inserted with Template:Unsigned2-->
::: Hello Carl (welcome back!) ;) --[[User:CSTAR|CSTAR]] 05:55, 1 March 2006 (UTC)
::: The consensus in '''your''' writings is such -- I have doubts about the scientific literature in general. But that has nothing to do with my assertion -- the nonpredictability is not due to indeterminancy, but due to external inputs. -- [[User:Arthur Rubin|Arthur Rubin]] | [[User_talk:Arthur_Rubin|(talk)]] 17:42, 1 March 2006 (UTC)
::::The citations in [[Arbiter (electronics)]] support the view that Arbiters once they have gone metastable have indeterminate behavior. Do you have any references to back up '''your''' personal view? <small>—''The preceding [[Wikipedia:Sign your posts on talk pages|unsigned]] comment was added by'' [[User:24.23.213.158|24.23.213.158]] ([[User talk:24.23.213.158|talk]] • [[Special:Contributions/24.23.213.158|contribs]]) 23:09, 1 March 2006 (UTC{{{3|}}})</small><!--Inserted with Template:Unsigned2-->
::::: The <U>article</U> [[Arbiter (electronics)]] supports my view. "Even synchronous computers need Arbiters to deal with input from outside the clock ___domain of the central processing unit: from keyboards, networks, disks, etc. " It's the external input which causes the nonpredictability, with Arbiters partially mitigating that unpredictablitility. [[User:Arthur Rubin|Arthur Rubin]] | [[User_talk:Arthur_Rubin|(talk)]] 23:16, 1 March 2006 (UTC)
::::::It is ''not'' the external input which cause the indeterminacy. According to the literature, it's the metastability which results in the indeterminate outcomes. Coming from the outside, inputs are unpredictable. If the external inputs cause metastability in an Arbiter then the outcome is indeterminate. <small>—''The preceding [[Wikipedia:Sign your posts on talk pages|unsigned]] comment was added by'' [[User:24.23.213.158|24.23.213.158]] ([[User talk:24.23.213.158|talk]] • [[Special:Contributions/24.23.213.158|contribs]]) 05:41, 2 March 2006 (UTC{{{3|}}})</small><!--Inserted with Template:Unsigned2-->
::::::The nonpredictability is called by outside inputs. You're the one calling it "indeterminacy" in this context. (Oh, and sign your comments. It's a separate violation of Wikipedia conventions, in addition to the violation if you edited any of the articles related to your research. — [[User:Arthur Rubin|Arthur Rubin]] | [[User_talk:Arthur_Rubin|(talk)]] 07:24, 2 March 2006 (UTC)
:::::::'''So it seems that you do not have any references to support your personal views on this matter?''' Is there not a Wikipedia policy against insisting on pushing your personal research point of view?
:::::::My browser says "You are not logged in. Your IP address will be recorded in this page's edit history."
:::::::<small><span class="autosigned">—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:24.23.213.158|24.23.213.158]] ([[User talk:24.23.213.158|talk]] • [[Special:Contributions/24.23.213.158|contribs]]) 08:13, March 2, 2006</span></small><!-- Template:Unsigned -->
:Back to one ":", or we're going to find ourselves all the way across the page.
:'''Your''' references and the articles you wrote do '''not''' support your theory that the nonpredictability is caused by indeterminacy. If you couldn't demonstrate it, it probable isn't supportable.
:As for signing -- your IP address is recorded in the history, but you still should record it on the talk page by ending your comments with "<nowiki>~~~~</nowiki>". — [[User:Arthur Rubin|Arthur Rubin]] | [[User_talk:Arthur_Rubin|(talk)]] 08:18, 2 March 2006 (UTC)
::The references in [[Arbiter (electronics)]] support the thesis that the outcome of an Arbiter is indeterminate once it becomes metastable. Note that there are several different kinds of indeterminacy from [[Talk:Indeterminacy in computation#Kinds of indeterminacy]] above.
::'''By your response you have confirmed that you do not have any references to support your personal views on this matter.''' This is against Wikipedia policy on pushing your personal research point of view. [[User:Anonymouser|Anonymouser]] 08:29, 2 March 2006 (UTC)
:::Apparantly you're too close to the issue, and are not allowed to edit the article in question, Carl. I'm willing to submit the issue of whether you've established '''your''' point and whether I've established mine to peer review -- remembering that it's our peers on Wikipedia rather than your peers in theoretical computation theory nor mine in mathematical logic. — [[User:Arthur Rubin|Arthur Rubin]] | [[User_talk:Arthur_Rubin|(talk)]] 15:57, 2 March 2006 (UTC)
:::: Please see [[Wikipedia talk:Requests for arbitration/Carl Hewitt/Workshop#The use of indeterminacy]] for an extended discussion of indeterminacy in arbiters, including a variety of references. --[[User:Allan McInnes|Allan McInnes]] <small>([[User talk:Allan McInnes|talk]])</small> 02:16, 8 March 2006 (UTC)
Has anyone thought that the indeterminacy is due to ''noise'' once the arbiter becomes metastable? [[User:24.23.213.158|24.23.213.158]] 23:03, 2 March 2006 (UTC)
:The noise argument looks very strong. If the inputs are the same within the noise bands, then what is the argument that the outcome depends on the input? Doesn't the outcome depend on the noise in the arbiter? <small>—''The preceding [[Wikipedia:Sign your posts on talk pages|unsigned]] comment was added by'' [[User:67.134.140.2|67.134.140.2]] ([[User talk:67.134.140.2|talk]] • [[Special:Contributions/67.134.140.2|contribs]]) 09:12, 8 March 2006 (UTC{{{3|}}})</small><!--Inserted with Template:Unsigned2-->
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==Introduction line==
Currently reads "Indeterminacy in concurrent computation is concerned with the effects of indeterminacy in concurrent computation" - so it's concerned with the effects of itself, nice. Surely someone can think of a better intro than that. [[Special:Contributions/82.39.140.240|82.39.140.240]] ([[User talk:82.39.140.240|talk]]) 22:36, 1 June 2009 (UTC)
:The line actually reads as follows: "Indeterminacy in concurrent computation is concerned with the effects of [[indeterminacy]] in [[concurrent computation]]." where the links provide additional meaning. But you are right that we should word it better.[[Special:Contributions/67.169.49.29|67.169.49.29]] ([[User talk:67.169.49.29|talk]]) 14:45, 2 June 2009 (UTC)
== Sense and nonsense ==
I'm sorry to be frank, but this section is nonsensical:
:Prolog-like concurrent systems were claimed to be based on mathematical logic
:Keith Clark, Hervé Gallaire, Steve Gregory, Vijay Saraswat, Udi Shapiro, Kazunori Ueda, etc. developed a family of Prolog-like concurrent message passing systems using unification of shared variables and data structure streams for messages. Claims were made that these systems were based on mathematical logic.[citation needed] This kind of system was used as the basis of the Japanese Fifth Generation Project (ICOT).
:Carl Hewitt and Gul Agha [1991] argued that these Prolog-like concurrent systems were neither deductive nor logical: like the Actor model, the Prolog-like concurrent systems were based on message passing and consequently were subject to the same indeterminacy.
The mathematical properties of a formal system has *nothing* to do with the physical implementations of it. One can formalize a programming language using a multitude of mathematical tools (such as, er, a logic..), but this unfortunately does not affect its physical realization.
To be clear: prolog *was* formalized (see http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.40.954 and its citations). This is a mathematical, abstract property, that *does not affect* the indeterminacy a physical system that implements prolog might have (other than the semantics of the language itself).
(Also, please note that many languages has been formalized with some 'logic', even the ones that does not favor the 'logic programming' paradigm) --[[Special:Contributions/187.40.172.119|187.40.172.119]] ([[User talk:187.40.172.119|talk]]) 03:25, 20 August 2010 (UTC)
The hard part is formalizing concurrency. The formalization of [http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.40.954 ISO Prolog] does not have any concurency. The physical indeterminacy of hardware used in the implementation of concurrent programming languages results in indeterminacy in the behavior of programs. It is well known that concurent programs cannot be reduced to pure logic (see [http://arxiv.org/abs/0812.4852 Common sense for concurrency and inconsistency tolerance using Direct Logic(TM) and the Actor Model]). [[Special:Contributions/64.134.238.26|64.134.238.26]] ([[User talk:64.134.238.26|talk]]) 20:54, 20 August 2010 (UTC)
== Indeterminacy definition is looped ==
The word "indeterminacy" is linked to some pages - which bring you back to here! <span style="font-size: smaller;" class="autosigned">— Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/142.167.186.3|142.167.186.3]] ([[User talk:142.167.186.3|talk]]) 01:17, 29 May 2012 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->
== Recommend this Article be Deleted ==
This article reads as if it were written by someone related to [[Carl Hewitt]] who is apparently on probation at Wikipedia. The text is mainly focused on the [[Actor model]] and [[Logic Programming]], there is very little about the general topic. When I googled " Indeterminacy in concurrent computation" on 16 April 2013, the hits I found on the first few pages of results seemed to be either directly derived from this article, or in recent articles by Carl Hewitt himself. Hence, I don't believe that Indeterminacy in concurrent computation is a worthy topic for Wikipedia.
Just to double check, I just googled "indeterminacy"+"concurrent computation", even when the two phrases are separated all the hits on the first few pages seemed to be derived from this article or the recent works of Carl Hewitt.
[[User:Pmokeefe|Pmokeefe]] ([[User talk:Pmokeefe|talk]]) 17:35, 16 April 2013 (UTC)
:Merge to [[Carl Hewitt]]? It ''might'' still be notable, even if it's his entirely his not-entirely-accepted theory. — [[User:Arthur Rubin|Arthur Rubin]] [[User talk:Arthur Rubin|(talk)]] 22:02, 16 April 2013 (UTC)
: I deprodded because at first glance, there are references independent of Hewitt. Merge sounds like a good idea if these independent refs turn out to be bogus. Feel free to bring this to AfD if notability is a concern. But non-neutrality of the prose by itself is a cause for editing and balancing, not deletion, if the sources are there to improve it. --[[User:Mark viking|Mark viking]] ([[User talk:Mark viking|talk]]) 22:19, 16 April 2013 (UTC)
::But what is written here is incoherent. I can't even figure out the point that is trying to be made here. There are a variety of theories in comp sci that describe non-determinism; none I know of are mentioned here. For example, the [[history monoid]] and the [[trace monoid]] explicitly describe non-determinism as the commuting portions of communicating systems. What the heck does the stuff here have to do with that, or, e.g. the [[calculus of communicating systems]] (CCS)? Or any of the text-book notions of reduction and [[confluence (computer science)]], which is how non-determinism is normally talked about? No one has re-rewritten or improved this article in 11 years, because no one can even figure out where to start, aside from deleting it entirely, and starting from scratch? Sorry to be so harsh, but I've read the text three times, and I can't quite figure out what it's trying to say.
::For example, lets look at the first three sentences of the current article:
:::''Patrick Hayes [1973] argued that the "usual sharp distinction that is made between the processes of computation and deduction, is misleading". Robert Kowalski developed the thesis that computation could be subsumed by deduction and quoted with approval "Computation is controlled deduction." which he attributed to Hayes in his 1988 paper on the early history of Prolog. Contrary to Kowalski and Hayes, Carl Hewitt claimed that logical deduction was incapable of carrying out concurrent computation in open systems[citation needed].''
:: The first two sentences seem to suggest that Hayes, Kowalski were ignorant of the [[Curry-Howard correspondence]] ?? Maybe in 1973, this was still an obscure, unknown thing? Or does "processes of computation and deduction" mean something else? WTF does this sentence even mean? Third sentence: "''logical deduction was incapable of carrying out concurrent computation in open systems''" Huh??? Does he mean that logic cannot be used to reason about open systems? Is this some arcane statement about [[Kripke semantics]]? What does this sentence refer to? what does it mean? OK, so next paragraph:
:::''Hewitt [1985] and Agha [1991], and other published work argued that mathematical models of concurrency did not determine particular concurrent computations''
::First reaction is: no-shit, sherlock, indeterminancy is a fundamental property of concurrent computation, and this would have been equally "obvious" by 1985 and 1991, so surely Hewitt and Agha are saying something more subtle than that. So it seems that sentence can be discarded, or re-written.. Next sentence: ''"The Actor model makes use of arbitration ..."'' but non-determinism is not specific to the actor model. Its made explicit in notions such as confluence, or the partially-commutative monoids, in general. So can we delete "Actor" from that paragraph? If this is done, what's left doesn't seem to say anything .. noteworthy.
::Then we move onto this sentence: ''Therefore mathematical logic can not implement concurrent computation in open systems.'' Huh? Mathematical logic, here, refers to what? [[Propositional logic]]? [[predicate logic]]? [[First-order logic]]? [[Higher order logic]]? [[Topoi]]? [[type theory]]? Is it trying to say that CCS and monoids and [[term rewriting]] aren't "mathematical logic"? What does the word "implement" mean? Does it mean "isomorphic" or "homomorphic"? Does it mean [[elementary extension]]? Does it mean something else? The trace monoids do provide a language for talking about homomorphisms of systems of concurrent computation; at least some of what [[model theory]] does has been extended to concurrent systems, its used in semiconductor design these days ([[boolean SAT]] and [[SMT]] solvers). So WTF? Can we scratch this sentence? One can proceed through this entire article, and tag it with ''dubious-discuss'' tags on every single sentence. I'd re-write this myself, except I can't figure out what the article is supposed to be about. [[Special:Contributions/67.198.37.16|67.198.37.16]] ([[User talk:67.198.37.16|talk]]) 04:27, 20 January 2017 (UTC)
== AfD candidate surely (or prompt rescue project) ==
Uh, someone knowledgeable needs to decide whether it's tendentious overreach to motivate an entire typology of concurrent computation on the seldom-observed [[Buridan's ass]] (see specifically [http://research.microsoft.com/en-us/um/people/lamport/pubs/buridan.pdf Buridan's Principle]) and ''then'' this article needs to be made comprehensible in a proper Wikipedia idiom, or it needs to die in a fire, with no in between. — [[user:MaxEnt|MaxEnt]] 22:58, 22 February 2016 (UTC)
:The irony is, of course, that this article is stuck in a meta-stable state between re-writing and deletion. Maybe, like Schroedinger's cat, it's both dead and alive.[[Special:Contributions/67.198.37.16|67.198.37.16]] ([[User talk:67.198.37.16|talk]]) 05:24, 20 January 2017 (UTC)
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