Talk:Von Neumann universal constructor

message: He observed that -
This citation is probably best derived from the writing contained within the text due Jeffress, Cerebral Mechanisms in Behavior - The Hixon Symposium: pages 30-31 contain the text "typical traits which appear in connection with mutation, leathally as a rule, but with a possibility of continuing reproduction with a modification of traits."  Clearly, the italicised portion of this quote is a satisfactory definition for the term open-ended evolution.  William R. Buckley 20:17, 11 March 2007 (UTC)
thread_title:  Citation 

message: What is this? Is this a turing-machine in a celular automata? Could someone explain this further? 84.59.213.173 (talk) 01:34, 31 January 2008 (UTC)
replies: text: It is not a TM in a CA.  Rather, it is supposed to be a UC in a CA.  In point of fact, it is a capable constructor, though not a UC.  It is also not a self-replicator.  For more information, see Nobili's website: http://www.pd.infn.it/~rnobili/   William R. Buckley (talk) 19:28, 1 March 2008 (UTC)

text: You might also review the proceedings for Automata 2008, which is searchable on Amazon.  William R. Buckley (talk) 23:23, 16 June 2008 (UTC)
thread_title:  Nobili-Pesavento 29-state 

message: These two articles ought to be merged because they both discuss the same subject matter.  —Preceding unsigned comment added by Maverick1701 (talk • contribs) 17:42, 1 March 2008 (UTC)
replies: text: Thes two articles should not be merged, and for the same reason as not merging with the *Self-replicating machine* article.  Universal assembler is one case, while the von Neumann universal constructor is another case.  Further the vN UC is like the Turing TM (both abstract, formal concepts), while the universal assembler (however vaguely described) is expectedly a real (physical) device.  William R. Buckley (talk) 19:09, 1 March 2008 (UTC)

text: As no further discussion has been observed, I am removing the flag.  William R. Buckley (talk) 17:48, 26 May 2008 (UTC)
thread_title:  Merging 

message: Ferkel: Is there no means to obtain better quality images; something that shows individual cells sufficient to determine state?  William R. Buckley (talk) 03:37, 16 August 2008 (UTC)
thread_title:  PNGs 

message: In your work on Pesavento, has it occurred to you that other, quite simple means exist to both render the design a self-replicator, and without need to rely upon collision of the construction arm with tape as a means to avoid the otherwise troublesome matter of constructing a certain cell?  Indeed, all one need do is to extend by quite some time the delay observed by the auto-retract signal, such that it is serviced after service of the corresponding construction signal; alter the visitation order of these signals upon the construction arm, and the problem disappears.  I think this is more elegant a mechanism, than is the mechanism which the Pesavento design employs.  William R. Buckley (talk) 03:48, 16 August 2008 (UTC)
thread_title:  More on Pesavento 

message: It should be noted that the reasoning for the declaration in Mange et al. is that the configuration there mentioned as being *consistent with the design of von Neumann* is so judged because it uses only the 29-states of von Neumann.  William R. Buckley (talk) 04:44, 16 August 2008 (UTC)
thread_title:  Mange: JvN Consistent Configuration 

message: Declaring NP32 the first universal constructor is perhaps going a bit too far, though it may require a bit of clever wording to correct.  My complaint is that NP32 is the first implemented UC for a CA.  It may be that other programs have expressed universal construction, though the fact is not recognised.  I am thinking of compilers, and viruses, etc.  William R. Buckley (talk) 04:52, 16 August 2008 (UTC)
thread_title:  Implementation 

message: It will require great care to properly handle the misconceptions implied by the simple definition of universal construction.  Part of the reason is that no vNCA Garden of Eden configuration is passive.  The best analogy comes from Douglas Hofstadter, who in Godel, Escher, and Bach: An Eternal Golden Braid mentions the phonograph player, which cannot play all possible phonographs: at least some of those phonographs will cause the player to break (think of standing waves in the player, whose energy increases by constructive interference with the waves emitted by the phonograph upon scratching it with a needle); there is no phonograph player that can play all possible phonographs.  Similarly, there is no universal constructor; all constructors are limited in their ability to construct, and this includes configurations which are not GoE's.  The key element in constructibility is the presence and nature of signal which is external to the constructor.  William R. Buckley (talk) 18:10, 17 August 2008 (UTC)
thread_title:  Simple Definition 

message: there are some assertions that VN's machine guarantees the possibility of mutation and evolution by natural selection. this seems like a pretty silly claim ... although a replicator with a changeable information component is necessary for evolution, it seems quite reasonable to suppose you can have a brittle self-replicator that won't function with any changes. The important fact seems to be that VN has proved the possibility of self-replicators at all, and the dubious assertion that this is a robust replicator capable of evolution, while interesting, seems to detract from the important point rather than improve the article. comments? 131.172.99.15 (talk) 03:02, 21 August 2008 (UTC)
replies: text: I mention this earlier on this Talk page, under the title Citation.  Von Neumann himself gave the argument, noting that arbitrary mutation would likely be lethal but that there was also a chance for evolutionary change; see the quote above.  (I argue that upon this expectation alone, von Neumann would have rejected any configuration which does not fulfill the behaviors of tape replication, configuration construction, controlled relative placement of these, starting of the construct, and a return to initial conditions - or some other means of repetitive replication; anything less is not a self-replicator - at best, just a constructor).  He tended to confine that change to the tape, the obvious means to heritability.  This does not imply that von Neumann excluded consideration of other mutation, such as that which might occur during construction of the daughter configuration, as opposed to the daughter tape.  The brittleness of one instantiation says nothing about other instantiations; there likely exist computational models which are not brittle; the classic complaint is that vNCA are brittle.  The proof of self-replicators is visible for all to see: biological organisms; machine self-replication follows directly.  What von Neumann did was show how to build such machines, by denoting both the logical requirements, and a set of suitable parts; indeed, for parts he did this twice (kinematic and tesselation), and toyed (TinkerToys, actually) with a third.  I agree most with your mention of the environment; the locus of the constructor.  However, that some construction occurs by interaction with the environment in no way implies that living systems (open-ended evolvers) cannot thereupon exist.  William R. Buckley (talk) 04:00, 21 August 2008 (UTC)
thread_title:  evolution 

message: It is interesting that while the concept of configuration size minimisation is discussed, especially considering the emphasis given Run-Length Limited encoding, yet it seems that such mechanisms do not yield the smallest configurations, nor the shortest tapes.  NCA configurations having 3343 cells, a tape of  44,150 cells, for 8830 5-bit instructions, and 3574 cells in the configuration, 37,780 cells in the tape, for 9445 4-bit instructions are known.  William R. Buckley (talk) 05:54, 15 September 2008 (UTC)
thread_title:  Configuration Size 

message: It is incorrect to call the NP29 configuration a universal constructor.  Indeed, none of the published *self-replicators* for vNCA (29 states)and NCA (32 states) is a universal constructor.  Not one of them can construct, for instance, the Real-Time Crossing Organ, as given by Gorman.  Properly, these configurations are all general constructors; they may construct any passive configuration.
Not only have I given two vNCA configurations which are self-replicators, I have also given a total of four NCA configurations which are also self-replicators; one of the latter is the quickest self-replicator for NCA, which has both nearly smallest corpus (a sister configuration is about 100 - 200 cells smaller) and the shortest tape yet given.  Use of Golly will quickly reveal the two flathead designs.  I am still waiting for a reply from Nobili, as to whether or not he can give a smaller configuration, or a shorter tape; one expects that time to self-replication is dependent upon these two parameters.
:On this point, neither of the vNCA configurations are the partial constructor.  In truth, I have published three vNCA self-replicators; two are holistic, and one is a partial constructor.  William R. Buckley (talk) 19:01, 19 February 2009 (UTC)
replies: text: As to the correctness of dates of publication, the partial constructor is the product of my graduate work, and was completed in December, 1999, when I submitted the corresponding documentation (a mix of thesis and project) in consideration of the award of master of science in computer science, January, 2000.  Hence, it is incorrect for other editors of this Wikipedia article to assert by text therein that Renato Nobili's works demonstrate a return to initial condition prior to such demonstration by my works; a minor point, but incorrect.  William R. Buckley (talk) 19:01, 19 February 2009 (UTC)

text: The two flathead designs given with the Golly 2.0 distribution are two of a set of three NCA self-replicators.  These three designs are at a sweetspot of the intersection between data and process (something that would be investigate-able were an algebra of algorithms available).  The simplest design has the smallest configuration size, and the longest tape.  The most complex design has the smallest tape, the largest configuration size, and the shortest time to self-replication.  All the configurations are of size less than 4000 cells, sans tape.  William R. Buckley (talk) 19:01, 19 February 2009 (UTC)
thread_title:  Article Misrepresentations as of 20081115 

message: I excised this phrase "and its offspring are not self-replicable" because it is ambiguous.
One may construct a tape of the 29-state configuration, and then the statement makes sense.
Except in the following case.  It is possible to construct a description (D) for machine A, which includes a description of the tape which machine A needs in order to self-replicate.  In that case, construction from D does not constitute self-replication.  This is true even if machine A is the machine which constructs according to the instructions in D.  Here, the offspring may well be self-replicable, even if their construction does not constitute an act of self-replication.  The reason is that machines derived from D will inherit tape A, not tape D.
The words *offspring* *daughter* and *construct* are synonyms for the product of construction.  I would suggest that the phrase is better expressed as "and its replicants are not self-replicable" to distinguish the nature of the construct - does it describe the machine which interprets the tape, or a machine other than the one which interprets the tape (which would be a construct).
The language for this distinction in cellular automata is not well developed.  William R. Buckley (talk) 23:13, 22 August 2009 (UTC)
thread_title:  Excised Detail - Capabilities of NP29 Configuration 

message: From my vague memories of a class in Artificial Life I took almost a decade ago, I understood this construction of von Neumann to be an attempt to produce a self-replicating Turing machine; this article appears to support that view. Could the wiki article detail how accurate that description is, i.e. how well did von Neumann fare in his attempt? Pcap ping 23:12, 1 September 2009 (UTC)
replies: text: If you look at the last theorem in that article (Smith, 1968), it's clearly possible to have a CA that is self-reproducing and computes any μ-recursive function, i.e. equivalent to a Turing machine. I've not read the article closely enough to tell if that is possible using von Neumann's construction or if substantial modifications are required. But this wiki article needs updating as it's missing a major aspect from the discussion. Pcap ping 23:24, 1 September 2009 (UTC)
replies: text: I will argue that Arbib is wrong, if indeed he states that von Neumann was interested in modeling a Turing machine.  It is clearly the case that von Neumann's cellular automata are capable of representing a Turing machine.  However, and this point is mentioned by von Neumann in Hixon, the Turing machine was simply a point of reference, a hint as to the nature of a machine which is capable of self-replication.  The important point is not computation, but construction.  Von Neumann modeled his notion of universal construction upon Turing's notion of universal computation.  In my view, no further claim should be made.  William R. Buckley (talk) 11:26, 24 November 2009 (UTC)
thread_title:  Clarification needed 

message: It is not exactly true to state that the traditional view of von Neumann's work in machine self-replication is that of the logical requirements for same.  Indeed, it is generally understood that Hixon addressed the logical requirements for non-trivial self-replication.  The opening paragraph of the section Purpose is therefore poorly constructed; Codd retained this orientation (as I recall, it is explicitly stated in his doctoral thesis), and the works of later researchers (such as Langton) were intended to address the minimisation of configuration, and simplification of underlying cellular automata, with the concomitant retention of non-triviality.  After all, one can go all the way to Ulam to see that self-replication is trivially achieved in some systems.  William R. Buckley (talk) 11:18, 24 November 2009 (UTC)
thread_title:  Traditional View 

message: Where do the numbers in the Table - Comparison of implementations - and in particular the number of time-steps for different implementations come from? Are there any peer-reviewed publications associated with these? The publications of Pesavento and Nobili that are linked from the article do not discuss practical implementations from what I can see. 
Alvis Brazma (brazma@ebi.ac.uk)  — Preceding unsigned comment added by 193.62.194.241 (talk) 10:33, 7 October 2013 (UTC)
thread_title:  time-steps for replication references 

message: Can somebody provide a download for phi9.rle and codon3.rle?
76.232.22.106 (talk) 18:43, 8 July 2018 (UTC)
thread_title:  Downloads 

message: I am constructing a machine that is capable of constructing any passive configuration and computing any μ-recursive function. I have estimated that it will take at least 1.3 million cells, not including any tapes. It is not an attempt to create the smallest universal computer-constructor. A configuration this large would take inordinate amounts of time and space to replicate, not to mention that it has 4 tapes. Here’s how it might replicate:
# Seek the first tape mark on data tapes 1 and 2, moving the construction arm to the right position.
# Seek the beginning of data tapes 1 and 2, ignoring all instructions.
# Seek the end of data tapes 1 and 2, ignoring all instructions, and extending the construction arm by 1 cell every time the tape head moves right by 1 cell.
# Seek the beginning of data tapes 1 and 2, copying the entirety of data tape 1 using the construction arm.
# Seek the first tape mark on data tapes 1 and 2, ignoring all instructions.
# Seek the second tape mark on data tapes 1 and 2, moving the construction arm to the right position.
# Seek the beginning of data tapes 1 and 2, ignoring all instructions.
# Seek the end of data tapes 1 and 2, ignoring all instructions, and extending the construction arm by 1 cell every time the tape head moves right by 1 cell.
# Seek the beginning of data tapes 1 and 2, copying the entirety of data tape 2 using the construction arm.
# Seek the second tape mark on data tapes 1 and 2, ignoring all instructions.
# Seek the end of data tapes 1 and 2, passing construction and articulation instructions to the signal discriminator and the construction arm, constructing the daughter automaton, including the program and marker tapes, then initializing and starting the daughter automaton, and finally returning the construction arm to it’s initial state.
# Seek the beginning of data tapes 1 and 2, ignoring all instructions.
# Reset the machine, and halt.
The tape uses full run-length encoding, *NOT* run-length *limited* encoding. This is mostly to minimize the length of the tape, because an overly long tape can cause slowdown. I might make a smaller one later. 76.232.22.106 (talk) 16:08, 25 August 2018 (UTC)
thread_title:  Universal computer-constructor 

message: Note: May include unreliable information
implementation         	source                        	ruleset             	rectangular area        	number of cells	length of tape	ratio  	timesteps for replication	tape code compression                                                  	tape code length                 	tape code type	replication mechanism	replication type	growth rate
Nobili-Pesavento, 1995 	tape.evn                      	Nobili 32-state     	97 × 170      	6,329          	145,315       	22.96  	6.34 × 1010              	none                                                                   	5 bits                           	binary        	holistic constructor 	non-repeatable  	linear
Nobili, 2007           	SR_CCN_AP.EVN                 	Nobili 32-state     	97 × 100      	5,313          	56,325        	10.60  	9.59 × 109               	run-length limited encoding                                            	5 bits                           	binary        	holistic constructor 	repeatable      	super-linear
Buckley, 2008          	codon5.rle                    	Nobili 32-state     	112 × 50      	3,343          	44,155        	13.21  	5.87 x 109               	auto-retraction                                                        	5 bits                           	binary        	holistic constructor 	repeatable      	linear
Buckley, 2008          	replicator.mc                 	von Neumann 29-state	312 × 132     	18,589         	294,844       	15.86  	2.61 × 1011              	auto-retraction                                                        	5 bits                           	binary        	holistic constructor 	repeatable      	linear
Buckley, 2008          	codon4.rle                    	Nobili 32-state     	109 × 59      	3,574          	37,780        	10.57  	4.31 x 109               	auto-retraction/bit generation                                         	4 bits                           	binary        	holistic constructor 	repeatable      	linear
Buckley, 2009          	codon3.rle                    	Nobili 32-state     	116 × 95      	4,855          	23,577        	4.86   	1.63 x 109               	auto-retraction/bit generation/code overlay                            	3 bits                           	binary        	holistic constructor 	repeatable      	super-linear
Buckley, 2009          	PartialReplicator.mc          	von Neumann 29-state	2063 × 377    	264,321        	NA            	-      	~1.12 x 1014             	none                                                                   	4 bits                           	binary        	partial constructor  	repeatable      	linear
Goucher & Buckley, 2012	phi9.rle                      	Nobili 32-state     	122 × 60      	3957           	8920          	2.25   	-                        	auto-retraction/bit generation/code overlay/run length limited         	3+ bits                          	ternary       	holistic constructor 	repeatable      	super-linear
76.232.22.106, 2018    	Unknown, project not completed	von Neumann 29-state	~2,000 × 1,500	~1,300,000     	Unknown       	Unknown	Unknown                  	none(program), auto-retraction/bit generation/run-length encoding(data)	5+ bits (program), 5+ bits (data)	binary        	holistic constructor 	repeatable      	linear
76.232.22.106 (talk) 16:43, 25 August 2018 (UTC)
thread_title:  My comparison of implementations 

message: I removed the "Constructor theory" wikilink from the See Also section. There is no published evidence of any connection between the Deutsch/Maletto Constructor Theory and von Neumann's Universal Constructor, or indeed any other concept in the field of cellular automata. If an editor wishes to add it back in, a reliable reference is needed to comply with Wikipedia policies, principally WP:NOR. David Spector (talk) 18:54, 12 September 2022 (UTC)
thread_title:  Removed "Constructor theory"