Talk:Constructor theory

This article is garbage.

The claim is made prominently that:"...a drop of dye can dissolve in water but thermodynamics shows that the reverse transformation, of the dye clumping back together, is not possible." This is false. However, for the purposes of this article, I merely DEMAND a (very) good reference, one from the thermodynamics literature rather than from the disciples of "Constructor Theory". In point of fact, many introductory courses (and a fair number of books) discussing diffusion of gasses state that it IS possible (although very unlikely) that the gas in a room will congregate in one corner of the room (thus causing all sorts of unfortunate side-effects in the room's occupants). This is no different, essentially, to diffusion in liquids: it IS possible but very unlikely. (Perhaps requiring many trillions of years (or more) to happen randomly.) Given that this is claimed to be a core motivation for the idea, I submit that the subject of this article either has no scientific merit, or has been greatly misunderstood by the editor(s) of this article. {It is both true that classical physics and quantum physics assume all (micro) changes are time symmetric (reversible), I don't believe anyone who has learned either could misunderstand that}173.189.73.230 (talk) 20:38, 26 November 2014 (UTC)

The fact that thermodynamics has an "arrow of time", while quantum mechanics and relativity do not, is a well-known conundrum. The dissolution of dye is an example that is traditionally used to illustrate the principle. Any "garbage" here is in the eye of the beholder. — Cheers, Steelpillow (Talk) 21:21, 26 November 2014 (UTC)

I read the edge.org article (now added to the External links section), but could not understand the supposed merit of "constructor theory". I googled, came here, and I still don't understand it. Maybe the article does not explain it well? Then I saw what Luboš Motl had to say about it. I always thought Motl was a huge blowhard, but maybe he has a point here. GregorB (talk) 12:41, 23 February 2015 (UTC)

"Unhelpful rant"

Um, Steelpillow - how exactly is The Edge article an "unhelpful rant"?[1] It is a description of the theory straight from Chiara Marletto, its codeveloper. And Edge.org is not some crackpot website either... GregorB (talk) 19:35, 23 February 2015 (UTC)

I owe you a sincere apology. I got muddled and thought you had posted the same link you give just above here. I have now restored your edit. While I'm here, I guess too there is a distinction between a lousily-written article and the lousy idea it is trying to explain. Since I too struggled to understand the theory, that is perhaps reflected in my poor presentation of it. I am not yet sure what to make of it, but Motl is certainly off-beam when he accuses Deutsch of not being smart. — Cheers, Steelpillow (Talk) 20:10, 23 February 2015 (UTC)

No problem at all. Motl's post could indeed be described as a rant (many of his posts are), and yes, it would be safe to say Deutsch is not an idiot either.

I mentioned Motl's post not because I agreed with everything he said, but rather to illustrate the impression I had, i.e. that the theory apparently makes no usable predictions or explanations and that its scientific merit is unclear, so maybe it's closer to philosophy of science than physics, and that's what makes it hard(er) to explain. GregorB (talk) 20:27, 23 February 2015 (UTC)

I suspect you are right about its foundational concepts being philosophical, although it seems more intended to help unify disparate areas of physics. Having physicists coin the jargon for a philosophical concept is perhaps unfortunate. — Cheers, Steelpillow (Talk) 22:25, 23 February 2015 (UTC)

Fringe theory

I added the {{Fringe theories}} template to the top of the article. According to WP:FRINGE, this article should make it clear what the subject's relationship is to current mainstream ideas. Most of the current sources in this article are written by proponents of this theory. The best sources to use when describing fringe theories, and in determining their notability and prominence, are independent reliable sources. In particular, the relative space that this article devotes to different aspects of the Constructor theory should follow from consideration primarily of the independent sources. Points that are not discussed in independent sources should not be given any space in this article (see WP:FRIND). Independent sources are also necessary to determine the relationship of this theory to mainstream scholarly discourse. --Dodi 8238 (talk) 23:27, 8 January 2016 (UTC)

I guess I prompted this. Fair enough about you, dropping my addition of "constructor theory of life" from the "See also". I admit I read upon (at the time, but not the "life" version) the "constructor theory" that it builds upon.

"The theory was developed by physicists David Deutsch and Chiara Marletto.[2]" with Deutch the pioneer of quantum computation (I guess quantum information, that he now regards "a special case of superinformation", his new idea). Yes, this is a relatively new theory (in that sense all are "fringe") and not yet mainstream, while I wasn't familiar with Marletto ("red linked", so maybe not as known) and "Chiara Marletto's constructor theory of life".

I'm looking into https://en.wikipedia.org/wiki/Wikipedia:Requests_for_arbitration/Homeopathy and putting a "fringe" label on at least the main theory seems harsh, when it's not put on such stuff and e.g. Water memory.. comp.arch (talk) 14:28, 9 January 2016 (UTC)

I am not saying that Constructor theory is pseudoscience or that it should be labeled as such. Alternative theoretical formulations from within the scientific community are not pseudoscience, but part of the scientific process (see WP:FRINGE/PS). My concern is rather that this article, in its current form, does not conform to Wikipedia's guidelines when it comes to new theories. Wikipedia is meant to be a tertiary source of information, summarizing the information gleaned from secondary sources, and in some cases from primary sources. Primary sources about research and investigations should only be used to verify the text and should not be relied on exclusively as doing so would violate Wikipedia's policies on original research.

Based on my searches, I can only identify three reliable secondary sources that are not self-published blogs. Two articles in New Scientist [2][3] and one in Scientific American [4]. Only one of them is currently used in this article.

I think that this article needs to be rewritten so that secondary sources (like the ones above) serve as the main sources of information about the subject. Also, the current level of acceptance among the relevant academic community should be clearly documented (see WP:FRINGELEVEL). --Dodi 8238 (talk) 16:27, 9 January 2016 (UTC)

I have now rebooted the article based on the reliable independent secondary sources that I have found. Feel free to expand the article based on information that can be directly attributed to reliable independent secondary sources (see WP:FRIND). --Dodi 8238 (talk) 13:27, 11 January 2016 (UTC)

A. First I want to say if you look at the official site you'll see: 1. "The Philosophy of Constructor Theory" (but clicking the link leads to "Constructor Theory" published[5] at Synthese: An International Journal for Epistemology, Methodology and Philosophy of Science "Volume 190, Issue 18 , pp 4331-4359"), that seems to be peer-reviewed (as it lists "paper", not just "pre-print"). Then there are (all only listed as pre-prints, but see below): 2. "The Constructor Theory of Information" (note this is the same as the former, so I assume we can say peer-reviewed?), 3. "The Constructor Theory of Life", 4. "The Constructor Theory of Probability" (new from last year, but brand-new revision this year, it seems not peer-reviewed).

About 2. and 3. being not peer-reviewed (based on "pre-print" and/or ArXiv, is the official site just out-of-date?). Do I read to much into "publishing" (and "Ed Board" as in peer-review) for 2. http://rspa.royalsocietypublishing.org/content/471/2174/20140540 and 3. http://rsif.royalsocietypublishing.org/content/12/104/20141226 ?

B. In case citations have any meaning, as [a substitute for] peer-review, I see, for 1.: 8 (6 excl. theirs) citations (latest last month)[6], 2.: 4 cit. (3 excl. theirs), 3.: 2 cit., one of from Journal of The Royal Society Interface.

C. I added the Medium's article (that is readable, the first one I read)[7], the first time I edited this article[8] and took out "notability"-banner. You may have taken it out, because it was only listed as "Arxiv Blog"? I do not know who wrote it, but based on the text: "That goal may now be a step closer thanks to the work of David Deutsch and Chiara Marletto at the University of Oxford in the UK." I assume it's not the authors. Anyway, the https://medium.com/the-physics-arxiv-blog seems to be writeup on a selection of [what I must conclude, the most] interesting articles, can't be on all of the pre-prints published. I think it should stay in, and similarly the "Scientific American Guest Blog"-article, that is under a name (and I guess, not anyone can publish at SciAm, even if they have a blog, its not some random "self-published" source). Also, while you say "Two articles in New Scientist" you dropped one of them[9].

D. I also think 1., 2., 3. and 4. should be linked to, as a service to the reader (not just the official link, that implies there might be only one theory/paper). Note 1. and 2. (the only one I've read) are for sure on the same theory or discussion of the same thing (at a different level). Just as they say quantum mechanics (an relativity) are "subsidiary theories" (and by extension biology (from memory also mentioned), then 3. is of course related). Nr. 3. seems however best viewed as a separate theory, and while notability has not been established separably, I just boldly added it here at the time. Isn't that ok, since(?) peer-reviewed and co-author of other paper? Her other paper 4. "The Constructor Theory of Probability" (also unread), seems also interesting: "I shall recast that problem in the recently proposed constructor theory of information - where quantum theory is represented as one of a class of 'superinformation theories', which are non-probabilistic theories conforming to certain constructor-theoretic conditions. I characterise the unpredictability of measurement outcomes exactly in constructor theory, showing that it necessarily arises in superinformation theories because of the impossibility of cloning certain sets of states. Then I explain how the appearance of stochasticity in (finitely many) repeated measurements arises under superinformation theories." My reading, "constructor theory" is not probabilistic (unlike major interpretations of quantum mechanics) with this new paper 4. explaining (presumably) how quantum mechanics arises. [See also QBism (that I'm just reading on, that might have similar/compatible ideas and Time Reborn: From the Crisis in Physics to the Future of the Universe, that I've read, and is very interesting, hopefully compatible.. while he lists Deutsch's older book/and the multiverse as the wrong idea.]

David Deutsch [10.22.12] (in "Interview"[10]) wrote (and I guess "The theory was developed"[11] in the WP article was based on that, while it got changed to "The theory was developed"): "In the case of constructor theory, how this is going to develop totally depends on what the theory turns out to say and even more fundamentally, whether it turns out to be true. If it turns out to be false that one cannot build a foundation to physics in the constructor theoretic way, that will be extremely interesting because that will mean that whole lines of argument that seemed to make it inevitable that we need a constructor theory are actually wrong, and whole lines of unification that seem to connect different fields don't connect them and yet, therefore, they must be connected in some other way, because the truth of the world has to be connected."

E. I'm not sure what and if the "Relationship Map"[12] tells you anything. comp.arch (talk) 16:17, 11 January 2016 (UTC)

Scientific American piece: [13] may provide some useful independent comment. — Cheers, Steelpillow (Talk) 16:39, 11 January 2016 (UTC)

Thanks, I may look into that. I de-rebooted, most of the article, thinking rebooting was (mistakenly) done because of perceived non-peer-review. Is it not ok, to leave some of primary source text in, as it is about what is claimed – even if it turns out to be false – as the article says "candidate", based on the theory not proven? That should clear that up? It's not like string theory has any proof.. either. What anyone says there is just commentary on math..

What I've looked into so far of non-author (or medium.com's) articles, the New Scientist one: "And for now, the new paper on Constructor Theory is only a statement of intent, says Vedral" [also at Oxford] and "Deutsch’s vision can be seen as a generalisation of the second law of thermodynamics, says Vlatko Vedral". Is there some rule about not relying on some people, such as at Oxford (I do not know any other connection, or familiar with that person)? Seth Lloyd also has comments in that article. comp.arch (talk) 17:44, 11 January 2016 (UTC)

Just realised that SA article was already linked to further up, silly me. I do think the reboot was an over-reaction: no doubt some content is questionable but the independent sources do cover a lot more ground than the current citations might suggest. This article needs evolution, not revolution. Oxford academics are perfectly acceptable sources here although, like anybody else, if their comments have not been reviewed by a reliable media editor then they must be treated with caution. — Cheers, Steelpillow (Talk) 19:17, 11 January 2016 (UTC)

Returning to the original topic of this discussion, I agree that the theory is very much on the fringe and we should mark it as such, but I am not sure how that is best done. — Cheers, Steelpillow (Talk) 19:20, 11 January 2016 (UTC)

From the Physics ArXiv blog:[14]. Not sure how reliable a source it is, though. — Cheers, Steelpillow (Talk) 20:35, 11 January 2016 (UTC)

progress in ergodic theory

The article currently includes this statement:

For example, a drop of dye can dissolve in water but thermodynamics shows that the reverse transformation, of the dye clumping back together, is effectively impossible. We do not know at a quantum level why this should be so.[1]

This jumps out at me because it apparently ignores 3 or 5 decades of research into ergodic theory. Now, I'm not saying there's a clean answer to this, but we did have people writing letters to PRL and writing PhD dissertations on exactly this topic a few decades ago. Mathematicians have even gotten prizes for clarifying aspects of this; Don Ornstein comes to mind. I'm not fixing this cause I'm a little burned out right now, but this should be corrected. 67.198.37.16 (talk) 22:56, 20 May 2021 (UTC)

Entire ”theory“ built on a very basic fallacy?

First of all, the article does not mention any predictions. So if that’s the case, it does not satisfy the basic definition of being science, as in, a hypothesis, let alone a theory.

Next, the article bases the reasoning for the entire thing on this false statement:

For example, a drop of dye can dissolve in water but thermodynamics shows that the reverse transformation, of the dye clumping back together, is effectively impossible. We do not know at a quantum level why this should be so.

Quantum mechanics, and indeed even classical mechanics does have a very simple explanation for it, that in my experience, everyone in the scientific community knows:

Given all the possible velocities of all the particles in the system, with equal probability, the subset where said reverse transformation happens is just very very small. So a growth of entropy is merely a very natural, obvious result of that.

In short: Unlikely ≠ impossible. Nothing in physics forbids it. It is not ”impossible“. Not even ”effectively“. In fact, given the size of the universe, it is pretty much guaranteed to happen somewhere. See also: The Boltzmann brain. The laws of thermodynamics are merely emergent properties. Not fundamental in themselves.

So it is pretty shocking, that there are people out there, who still don’t know this, yet consider themselves experts enough, to form such ”theories“. In terms of lack of scientificness, this seems to be somewere between string ”theory“ and ”electric universe“/”time cube“ nonsense. And if it isn’t, this article even more desperately needs a complwte rewrite.

— 2001:4DD1:13E4:0:6938:9E4:5C04:8EC7 (talk) 12:18, 28 October 2021 (UTC)

nonetheless it is notable and is being observed with interest by the professional and general community —¿philoserf? (talk) 13:45, 28 October 2021 (UTC)

Impossible?

"In constructor theory, a transformation or change is described as a task. A constructor is a physical entity that is able to carry out a given task repeatedly. A task is only possible if a constructor capable of carrying it out exists, otherwise, it is impossible."

So vaporizing Hiroshima with an atomic bomb was impossible?

- It certainly seems to have been a transformation.

- It seems to be impossible to have carried out the task repeatedly, therefore there was no constructor.

- Therefore the task was impossible.

Or am I misunderstanding?

Paul Magnussen (talk) 01:20, 30 October 2021 (UTC)

Von Neumann

I am quite certain that John Von Neumann's ideas concerning the universal constructor were an important influence upon Marletto and Deutsch. It may be wise to insert something about it in the page. Gandalf 1892 (talk) 03:41, 8 April 2022 (UTC)