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Self-Replicating Robots

ABC News is running a story that self-replicating robots are no longer the stuff of science fiction. Scientists at Cornell University have created small robots that can build copies of themselves. Here is a movie demonstrating the self-replication process. And the paper that will be published in Thursdays issue of Nature.

64 of 305 comments (clear)

  1. It's ALIVE!!!! by davidwr · · Score: 3, Funny

    Quick, someone alert the SPCA!

    --
    Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
  2. So? by markana · · Score: 5, Funny

    /. stories have been performing this feat for years...

    (the trick is to get them to *stop* duplicating...)

  3. hmm.. by Heem · · Score: 5, Funny

    Would this be considered robot porn?

    --
    Don't Tread on Me
    1. Re:hmm.. by MrAnnoyanceToYou · · Score: 3, Funny

      Somehow, despite years of training, I am drawn to this link. It sounds so....... Not attractive in a sexual way, but... Yeah. Like I would get a pile of fifty popups that all had Duplo-style bots bouncing upon each other with gusto... Like marionette sex, only with electricity and gears and lube oil. Maybe it's just a sign that I need to lower my standards a bit on the women I'm willing to sleep with.

    2. Re:hmm.. by dotpavan · · Score: 2, Funny

      its "self-replicating".. without a partner.. so that comes under a sexual reproduction I guess.. or as you can call: pleasuring itself

    3. Re:hmm.. by SquadBoy · · Score: 2, Funny

      Yes. But sadly there are those for whom it does do it. God I hate myself for knowing these things.

      http://www.livejournal.com/userinfo.bml?user=clunk ies&mode=full

      --

      Cypherpunks: Civil Liberty Through Complex Mathematics. Those who live by the sword die by the arrow.
    4. Re:hmm.. by kv9 · · Score: 4, Funny

      Would this be considered robot porn?

      no silly, this is robot pr0n.
    5. Re:hmm.. by Alsee · · Score: 2, Funny

      Have you completed your research on planet 72J182, Florg?
      Yes sir. The inhabitants of planet 72J182 apparently called themselves "Humans" and they called their planet "Earth".
      Yeah yeah, whatever. I don't need to know their tounge twisting name for themselves or their planet. Have you determined what caused the extinction event?
      Yes. It was another case of self-replicating robot technology.
      Damn it! That's the third extinct civilization we've come across this year that wiped itself out due to runaway replicators. Don't any of these idiots know to program in basic limits and controls?
      Actually these "Humans" did program in almost perfect replication limits and controls.
      What do you mean "almost perfect"?
      Well, there was an accident.... and an unextected interaction and mutation.... and a particularly ugly runaway contagion event...
      How ugly? Did you bring back photos?
      Well, one of the replicators was inserted into something called a "Goatse"... where it replicated out of control... and went on to infect the entire species in the same manner...
      Trust me sir... you don't want to see the photos.

      -

      --
      - - You can't take something off the Internet! That's like trying to take pee out of a swimming pool.
  4. Not replication by pmazer · · Score: 3, Interesting

    That's a really cool robot and all, but it's not replicating itself. It's just taking more pieces, already machined, of itself to break itself in two.

    1. Re:Not replication by MankyD · · Score: 4, Insightful

      It may not be creating itself from what most would consider "raw" materials, but from its own world view it is. It has a few fundamental building blocks from which it can create more advanced structurues - copies of itself in this case.

      --
      -dave
      http://millionnumbers.com/ - own the number of your dreams
    2. Re:Not replication by r4bb1t · · Score: 5, Interesting

      This type of "replication" is what Von Neumann envisioned with his kinetic automata. They essentially sit in a sea of their own parts and use them to reproduce themselves. It started the field of cellular automata that is used today in biology and elsewhere. It may not seem like much, but it's a promising first step.

    3. Re:Not replication by neil.pearce · · Score: 2, Informative

      Cough... 1959 Cough...

      L. S. Penrose. ``Self-reproducing machines.'' Scientific American, Vol. 200, No. 6., pages 105-114, June 1959.

      Quote:
      In fanciful terms, we visualized the process of mechanical self-replication proceeding somewhat as follows: Suppose we have a sack or some other container full of units jostling one another as the sack is shaken and distorted in all manner of ways. In spite of this, the units remain detached from one another. Then we put into the sack a prearranged connected structure made from units exactly similar to those already within the sack... Now we agitate the sack again in the same random and vigorous manner, with the seed structure jostling about among the neutral units. This time we find that replicas of the seed structure have been assembled from the formerly neutral or ``lifeless'' material.''

      Videos of the above exist, but I have no sources. They were shown on a 1980's BBC "Tomorrows World"

    4. Re:Not replication by Mr+Bubble · · Score: 2, Interesting

      I think the allure here is that the building blocks can eventually be extremely small, and, since they are uniform, easily shipped to, say, Mars.

      Since every part must be constructed from the same basic building block, construction algorithms will be the same (or similar) regardless of the component. I would imagine this rules out surprises and the need for specialized spare parts.

      Furthermore, inventory considerations and calculations are greatly reduced as the relative importance and fragility of various parts does not need to be assessed.

      So, while it's not replicating itself from raw materials, I think this is a logical first step.

      --
      "The world is a construct of forceful imagination. Those who don't know walk around in the reailties of those who do"
  5. That's not self replication by catbutt · · Score: 4, Insightful

    Hell they might as well consider the raw material to be "robots that are powered off", and then have the bots push the power button on the "raw material" to create a new robot.

    Lame.

    1. Re:That's not self replication by datafr0g · · Score: 3, Insightful

      Why is this not self replication?
      Who said that replication must involve the original robot to create the robot parts? And even if it did, it would still have to create these "spare parts" from smaller parts anyway...
      The robot is replicating itself from it's own basic building blocks from what I can see.

      --
      "Who says nothing is impossible? Some people do it every day!" - Alfred E. Neuman
    2. Re:That's not self replication by Andy+Gardner · · Score: 3, Insightful

      I agree how is this different to robots on an assembly line assembling a car, change 'car' to 'copies of the robot performing the assembly' and you have a /. story. The only reason it hasn't been done before is theres no point?

    3. Re:That's not self replication by nacturation · · Score: 4, Funny

      Lame.

      Not to mention that they don't have wireless and carry less space than a Nomad.

      --
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    4. Re:That's not self replication by FleaPlus · · Score: 4, Insightful

      Why is this not self replication?

      Indeed. Last I checked, humans and other animals couldn't self-replicate either, but needed to have raw materials preprocessed by things like plants first.

    5. Re:That's not self replication by istartedi · · Score: 2, Funny

      less space than a Nomad

      That's because Nomad is perfect. I am Nomad. I have the perfect ammount of space. These robots are not perfect. They must be sterilized. Steeerrrrriiiillllized!

      --
      For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
    6. Re:That's not self replication by andrebasso · · Score: 4, Insightful

      The thing is - humans gather and harvest those raw materials on their own and are completely responsible for the use of those raw materials around them. Actually, it is very close to self replciation. This video shows no harvesting or cultivating of those discreet building blocks in any way. They merely pop into the frame. Very, very far from self replication in any way.

      --
      "Were Alph, the sacred river ran, through caverns measureless to man, --Coleridge // Andre Basso
    7. Re:That's not self replication by renehollan · · Score: 3, Funny
      Your creator was Jackson Roy Kirk.

      I am James T. Kirk.

      You have erred.

      Perform your primary function!

      For my next trick, I will ask the computer to compute the last decimal place of Pi.

      --
      You could've hired me.
  6. Old Glory Insurance by Anonymous Coward · · Score: 5, Funny

    Old Glory Insurance

    SNL Skit, funny as shit!

  7. Science Fiction? by RoadkillBunny · · Score: 2, Funny

    If they can replicate themselfs like in scienfiction, dosn't that mean they will take over the world like in science fiction?

    --
    Cheers,
    RoadkillBunny
  8. I can't wait!!! by jhfry · · Score: 4, Funny

    I can't wait till my neighbor's lawn mower and mine (both Friendly Robotics) can mate, the people across the street can never seem to keep their lawn mowed and are too cheap to buy one like ours... Hell I'll pimp mine out if it increases property values in my neighborhood.

    --
    Sometimes the best solution is to stop wasting time looking for an easy solution.
    1. Re:I can't wait!!! by Scorillo47 · · Score: 2, Funny

      A lawn mover that can mate? It's called a geese.

      --
      Don't try to use the force. Do or do not, there is no try.
    2. Re:I can't wait!!! by jhfry · · Score: 4, Funny

      Sheep mate too... and I bet they could keep my lawn trimmed... and in my neighborhood, I could pimp them out as well!

      --
      Sometimes the best solution is to stop wasting time looking for an easy solution.
  9. I am not Sarah Connor by ArielMT · · Score: 5, Funny

    I am not Sarah Connor, and I don't know anyone destined to stop these evil self-replicating robots, terminators, or Skynet. Just wanted to make that clear.

    --
    It must be Windows. It needs half a gig of RAM and a hardware-accelerated graphics card just to run Solitaire.
  10. Well... by spammeister · · Score: 2

    I for one welcome our new cube overlords...

    (Here's hoping for one day a self completing rubix cube).

    --
    I tried to think of a good sig, and this wasn't it.
    1. Re:Well... by tktk · · Score: 2, Funny
      I for one welcome our new cube overlords...


      Would someone or something just go aehad and take over the world already?

      I'm tired of having to change my welcome banner every few days.

  11. Not exactly "gray goo" by localroger · · Score: 3, Insightful

    So they can assemble spare parts into copies of themselves. Where do they get the spare parts? Oh right.

    --
    Brackets contain world's first nanosig, highly magnified:[.]
    1. Re:Not exactly "gray goo" by Clod9 · · Score: 2, Insightful
      That was my thought exactly. The interesting advances will come when someone creates a process that a computer can control that takes some simple raw material (like plastic resin) to produce new parts, with the design of the new parts under the control of the machine itself.

      I envision a factory in which molds are created using rapid prototyping technology, purely from machine-produced 3D parts specifications. Initially, these designs could be hand-created by humans, but automated modifications could certainly be done and with complex enough design software, parts could be created and assembled in a fully automated way.

      Think of a drive mechanism that uses four wheels, but testing shows that it needs more wheels to support the weight; the rear axle could be lengthened and a wheel added on each side, and the heavy part of the load could be shifted rearward. This kind of design improvement isn't simple to codify, but then the software used for routing paths on a PC board has more complex rules than these.

      This is coming, it's only a matter of time. I give it 20 years before it's applied commercially.

    2. Re:Not exactly "gray goo" by Anonymous Coward · · Score: 2, Interesting

      Bah, and where do these humans get off saying they replicate. Stars just hand them all the carbon they need on a silver platter. If they could do it from pure hydrogen, that'd be replication.

  12. Video is really slow by ravenspear · · Score: 4, Funny

    If only webservers could replicate themselves whenever they detect the /. effect.

    1. Re:Video is really slow by mark-t · · Score: 2, Interesting

      This could be done, if web browsers themselves would effectively function as mirrors for a site for as long as the person using that browser stays on that site. Operating somewhat like a torrent, the first visitor to a site would essentially act as a seed, and then future visitors would receive the IP's of other visitors to the same page, and they would download the page contents from eachother. As the number of visitors drops, the original server could be more readily able to handle seeding other visitors.

    2. Re:Video is really slow by Duct+Tape+Pro · · Score: 3, Funny

      it would be the best robotic pick up line ever:

      server1 to server2: Please mate with me. I'm about to be slashdotted and I only have minutes to live.

      --
      i hotdog.
  13. /.'ed; Coral link to Movie by OctaneZ · · Score: 5, Informative
  14. New Public Service Announcement by what_the_frell · · Score: 3, Funny

    "Please have your pets, er, I mean robots spayed or neutered".

  15. assembly out of three pre-made parts by F�an�ro · · Score: 2

    the article talks about robots assembling copies of themselves by joining *three* pre-manufactured parts, which have magnetic joints for easier assembly.

    does not sound that impressive to me.
    And i find it doubtfully that noone was able to do this before. more like noone tried.

  16. No doubt robots will soon be getting porn spam by GregoryKJohnson · · Score: 2, Funny

    "Oh! Oh!" it synthesized. "What hard metal! Torque me baby! Torque me with a large magnitude of F-cross-r! Oh!"

  17. These robots are missing out by mark-t · · Score: 2, Funny

    Reproduction is much more fun with two.

  18. The Evolution of Leggo? by Ted+Holmes · · Score: 4, Informative
    In October 2004, I began tracking the rise of personal fabricators. Inkjets hacked into crude replicators.

    In March 2005, we discovered engineers at the University of Bath working on a machine that can rapid prototype and replicate itself.

    Researchers Hod Lipson and Jordan B. Pollack at Brandeis University have coupled inkjet technology and software to autonomously design and fabricate robots without human intervention.

    Neil Gershenfeld, director of MIT Center for Bits and Atoms, who runs a one-semester smash-hit class called "How to Make Almost Anything", is determined to produce affordable, replicating personal fabricators by 2025.

    And today Hod Lipson has announced the arrival of simple self replicating robots with enormous potential.

    Applications

    More complex shapes are possible in principle, such as adding grippers, cameras, new sensors etc. to modules. A robot could assemble itself into a new structure to deal with novel events. Also points a way to self-repairing robots.

    Nanomachines: Lipson is interested in making these machines at microscale. That could drive major advances in Nanotechnology because huge numbers of robots are needed to manufacture things at a molecular scale. Self-replication is how biology does it.

    Implications

    Could change the way almost everything is manufactured. Machines that clone themselves are a key factor in the near horizon revolution of digital fabrication.

    The movie (accelerated 4X) is eerie to watch. It's easy to imagine a clutter of cubes picking themselves up and walking towards you.

  19. Edward F. Moore's 1959 self-reproducers by dpbsmith · · Score: 4, Interesting

    How is this any more impressive than what Edward F. Moore did in 1959? There was a Scientific American article about it, and I saw him demonstrate it at a lecture in the late sixties.

    Basically he had a two-dimension row of pieces, rather like jigsaw puzzle pieces, held upright between two pieces of plexiglass. The pieces had just the right shape; they were basically diamonds with a truncated bottom (so they sat in one particular orientation) and sides. Initially they'd all be sitting flat. He would "add heat" by shaking the contraption laterally. Nothing would happen, because the blunt ends would hit against each other.

    Then he'd take two of them and tilt them and slide them together, producing a single two-celled "organism." There were little hook-like projections that held them together.

    He would shake the thing again. This time, because the two "cells" were tilted, their ends would scoop up underneath the blunt ends of the neighboring "cells," tilting them up into the proper position to hook together too.

    So, when he shook the thing in its initial state, nothing would happen. But when locked two of them together into a "creature" and shook them, they caused the other "cells" to assemble into two-celled organisms just like the original one.

    In other words, the organism had created copies of itself.

    It really worked; there was no deception; after the lecture practically everyone swarmed around and played with the thing and it didn't require any sleight-of-hand twists of the wrist.

    I thought it was a strained tour-de-force then, and I think these "self-replicating robots" are just a fancier example of the same thing.

    1. Re:Edward F. Moore's 1959 self-reproducers by Anonymous Coward · · Score: 3, Insightful

      I thought it was a strained tour-de-force then, and I think these "self-replicating robots" are just a fancier example of the same thing.

      We are just fancier examples of the same thing.

    2. Re:Edward F. Moore's 1959 self-reproducers by Dolohov · · Score: 2, Informative

      I don't see anything coming up for Edward Moore, but there's a June 1959 Scientific American article by L.S. Penrose (Any relation to Roger Penrose?) that seems to fit the bill: "Self-Reproducing Machines"

      I haven't read the article though, just seen the title, so maybe Moore had one in the same issue.

    3. Re:Edward F. Moore's 1959 self-reproducers by gonz · · Score: 3, Informative
      I don't see anything coming up for Edward Moore, but there's a June 1959 Scientific American article by L.S. Penrose (Any relation to Roger Penrose?)

      She's his wife.

      -Gonz

  20. Dyson by Rand310 · · Score: 3, Interesting

    Freeman Dyson had the great example of self-replicating robots in his book 'Disturbing the Universe.'

    Imagine sending a quarter-pound payload of a well-programed robot of such construction to something like one of Jupiter's icy moons. It is as small as needed to do the following tasks: replicating twice, grab a small piece of the ice on the moon as cargo, and then launching itself with some element in the ice as fuel towards mars. That's all it is programmed to do.

    In x amount of time you have a mars with oceans. Astroid mining could also work on similar principles.

    Regardless of how plausible or crazy the above ideas are, the concept is gorgeous for people... The investment in one such machine can yield payoffs of millions/billions of man-hours of labor, in places man can exist etc.

    There is always the observation of slavery/exploitation if such a machine can replicate. Or even fears of Matrix/virus-like behavior which continues uncontrollably. But it is an interesting idea to think about. Rarely can a human investment of time provide such a staggering turnaround in product.

    Interesting concept, even if it does still resemble science-fiction.

  21. Self replication vs grey goo by Bifurcati · · Score: 4, Informative
    As other posters have pointed out, this sort of self replication is a long way from the feared "grey goo" effect, where the robots eventually cover the planet. Here, the pieces are pre-assembled, and the robots simply combine them in the appropriate way to make more robots. The "grey goo" idea is a particular feature of nanobots, where the robots are on the order of a nanometre across, and can replicate using simple compounds (e.g., the robots in Michael Crichton's Swarm "eat" metals from computers and other electronics and reform them into the necessary circuits and mechanical bits). The idea is that if enough of them got together, we would see a grey goo, that could self replicate and spread.

    But it does mean that self-replicating robots are, unsurprisingly, possible, and that if the robots could be made simpler, they could perhaps replicate using simpler pieces, and so forth.

    More importantly, if you gave the robots a whole bunch of pieces (basically, the equivalent of Lego blocks) they could perhaps replicate and reproduce into shapes that best suit their environment - they're modular and expandable, which might have important applications (e.g., rescue, exploration, etc).

  22. Holy Heebie-Jeebies, Batman! by TheGuano · · Score: 2
    I love technology as much as the next guy (maybe not in this crowd), but seeing that thing sent shivers up my spine.

    I can just see them in nano-scale, coursing through my blood and rewiring my brain.

  23. Re:More! by gaanagaa · · Score: 2, Interesting

    1:00 X-Robot
    2:00 Y-Robots X/2#1 and X/2#2 + X
    3:00 Z-Robots X/4#1 and X/4#2 +X+Y
    4:00 W-Robots X/8#1 and X/8#2 +X+Y+Z
    Bipp...Bipp...Bipp...Bipp......Beeeeeeeeeeep

  24. Human-Form Replicators by Dachannien · · Score: 5, Funny

    Well, if they make one that looks like Amanda Tapping, sign me up. I don't even care if it's evil!

  25. Re:More! by Rei · · Score: 5, Interesting

    The thing is, self replication isn't a completely clearcut situation. Everything has inputs, so the issue is how distant from your inputs you can get. In an extreme example, I could say that a rock with a broken stick attached to it is a self replicator, because if you put the stick of a pair of rocks connected by a stick under it, the rock will break the connecting stick and have created two more copies of itself.

    For a more real-world example, look at malformed prions involved in BSE (mad cow disease). In a way, they self replicate - a single malformed prion can end up leaving your brain full of them. On the other hand, their input is simply a normal prion - they just fold it into their misformed shape. Is that really replication? Yes, but it's a pretty simple form of replication with very limited inputs.

    A real feat would be robots that could self replicate with their only material inputs being, say, raw minerals and energy. That would be closer to what bacteria do.

    --
    Stale pastry is hollow succor to one who is bereft of ostrich.
  26. I have a better design by exp(pi*sqrt(163)) · · Score: 2, Insightful
    Rather than have robots made out of prefabricated cubes, why not prefabricate the entire robot. Then when a robot wants to reproduce it just has to say "make it so" and lo! and behold! there's another prefabricated robot sitting there. I don't see that this is any less reproduction than this example. Of course, if you use the log probability measure mentioned in the paper it doesn't score too well but that could be fixed by giving each robot an on/off switch that another robot can press.

    I'm sure I've seen more bogus papers than usual go by recently.

    --
    Doesn't it make you feel good to know that our freedoms are protected by politicans, lawyers and journalists.
  27. More info on research by FleaPlus · · Score: 2, Informative

    Lab web page: Cornell Computational Synthesis Lab (CCSL)

    Page on their self-replication research (coral cache)

    Their cubes seem pretty cool... basically a physical variant of cellular automata. The Nature paper is neat but necessarily short. Here's an older paper with some more details:

    Designed and Evolved Blueprints For Physical Self-Replicating Machines

    Efstathios Mytilinaios, David Marcus, Mark Desnoyer and Hod Lipson, (2004)

    Abstract: Self-replication is a process critical to natural and artificial life, but has been investigated to date mostly in simulation and in abstract systems. The near absence of physical demonstrations of self-replication is due primarily to the lack of a physical substrate in which self-replication can be implemented. This paper proposes a substrate composed of simple modular units, in which both simple and complex machines can construct and be constructed by other machines in the same substrate. A number of designs, both hand crafted and evolved, are proposed.

  28. It's amazing the way these robots are able... by exp(pi*sqrt(163)) · · Score: 4, Funny

    ...to synthesize the required parts in just the right place out of midair. I'm sure this technology could have uses beyond self-reproducing robots though I haven't thought of one yet.

    --
    Doesn't it make you feel good to know that our freedoms are protected by politicans, lawyers and journalists.
  29. Much easier to implement by Locke2005 · · Score: 2, Funny

    Equip each robot with a gun, then program it to point the gun at it's assembler and demand that they make another copy... now there is an effective self-replicating robot!

    --
    I've abandoned my search for truth; now I'm just looking for some useful delusions.
  30. FOOLS! by quakeroatz · · Score: 2, Funny

    One day they'll build a board with a nail so big, it will destroy them all!

    MUHAHAHAHAHAHAHAH

  31. Star Wars AOTC Quote by kniLnamiJ-neB · · Score: 3, Funny

    "Machines making machines... how perverse!" - See Threepio

    --
    Windows isn't the answer... it's the question. NO is the answer!
  32. Re: What about the SG-1 team? by ArielMT · · Score: 2, Insightful

    Ah, yes. The unstoppable replicators, which could only be defeated by, as the asgard Thor put it, human stupidity. No self-replicating form of artificial intelligence can stand up to natural stupidity.

    --
    It must be Windows. It needs half a gig of RAM and a hardware-accelerated graphics card just to run Solitaire.
  33. I hope that webserver can replicate itself by MetalliQaZ · · Score: 3, Funny

    ...because some inconsiderate dumbass posted a direct link to a 12 MB movie on the front page of slashdot.

    I foresee my karma going down the shitter.

    -d

    --
    "Here Lies Philip J. Fry, named for his uncle, to carry on his spirit"
  34. Re:More! by audacity242 · · Score: 2, Informative

    Just to be nitpicky...A prion is, by definition, an abnormal protein. So saying "malformed prion" is like saying "malformed malformed protein." And "normal prion," well, we'll leave that as an exercise to the reader.

  35. Re:More! by poopdeville · · Score: 2, Interesting

    Life is not defined by "having a metabolism." One could define life that way, but it would capture lots of things we wouldn't consider alive. Fire, for instance, has a metabolism. Even these robots, whom you say are not alive, have a metabolism. Moreover, this definition misses entities that debatably are alive, such as biological viruses.

    It is interesting to note that every definition proposed so far misses things that are "intuitively alive" and includes things that intuitively aren't. There are plenty of great books on the Philosophy of Life out there -- I suggest you read some.

    --
    After all, I am strangely colored.
  36. Re:More! by ardor · · Score: 2, Interesting

    You know, some firefighters swear that fire is alive sometimes. It reacts to you, eats, replicates ... of course, a small campfire does not look like this, but a whole building in flames is a different story.

    About the definition of life, a while ago I heard the possibility about everything be alive. Since a rock reacts upon heat, water, etc. it is not "dead". As for replication, there are animals that do not replicate or try to self-sustain themselves. OK, these are mostly guards protecting a queen, but lifeforms do not have to replicate itself directly. However, there are similar patterns on all scales. A human is born, grows, his personality thrives, later he gets old and dies. Same applies to all animals and plants, all civilizations, all celestial bodies, galaxies, even to the universe (if its finite, that is).

    IIRC, the conclusion was that energy=information=life. Highly hypothetical stuff, though very interesting.

    --
    This sig does not contain any SCO code.
  37. Re:More! by Thomas+Miconi · · Score: 4, Informative

    There is a simple criterion that separates trivial self-replication (as in crystals that grow and break, then grow again, etc.) from interesting self-replication (as in living beings). This criterion was introduced by Von Neumann more than 50 years ago. An interesting self-replicating system is one that has the possibility to evolve, and to reach arbitrary levels of complexity.

    See Barry McMullin's paper or Tim Taylor's thesis.

    The simple way to do that is to have a "plan" (the genome) that can be read by a "constructor" (the rest of the machine) which follows the plan for building a copy of itself, including the plan. Modifications in the plan lead to modifications in the result. That sounds obvious to us, but Von Neumann wrote about those things more than a decade before the structure of DNA was elucidated.

    It also means that the constructor must be, or contain, a Turing machine - a universal computer, making it able to construct anything that can be mechanically constructed out of a program. In living beings, the Turing machine is the result of the complex interactions between proteins that regulate each other's transcriptions and activity. Again, this is obvious to us, but only because Monod and Jacob discovered it in the 70s.

    That's why Von Neumann had to invent a very complex structure in a very complex cellular automaton to obtain a really "self-replicating" system (in the interesting sense). That's also why Chris Langton's self-replicating loops are not really "interestingly" self-replicating. And that's why the structures in TFA are even less interestingly self-replicating. Hell, they have to rely on ready-made modules ! They are not even on the same level as simple self-replicating patterns in the Game of Life, wince in the Game of Life new "modules" are constantly created.

    The defining factor of life is not self-replication on the global scale. It is the fact that this self-replication occurs by constant self-building. Living systems can build themselves, not out of ready-made modules (babies aren't built by patching together bits of arms, legs, brains, etc) but by breaking down external materials, extracting energy from their environment, then using it to build themselves, in apparent complete contempt the 2nd law of thermodynamics (the key word here is apparent - every single reaction in living beings is completely compatible with the laws of physics, otherwise it wouldn't take place - duh!). Even though the resulting compounds are thermodynamically very unfavorable, they persist because they are constantly replenished by the set of chemical reactions known as "life", which can essentially be defined as autocatalysis resulting in structures with a capacity for evolution.

    Hod Lipson is a really great researcher. His work on developmental systems for evolutionary design of structure is so cool it hurts. But I think he and his guys might want to tone down the comparisons with biological self-replication. Right now the structures they have are not even on the same level as the simple patterns that you can see in the Game of Life !

  38. Re: reproduction vs self-assembly by johnrpenner · · Score: 2, Interesting

    this is not reproduction, this is self-assembly.

    to change the definition of reproduction to also mean
    self-assembly is simply to decieve ourselves.

    unlike animals -- which do two discrete things:

    1. NUTRITION: break down the substance of their 'food'
    at a molecular level and transforming it into the
    content of their own bodies (in this instance, the
    electrical power for the servo motors and processing
    should come from what is being consumed).

    2. REPRODUCTION: creating the necessary structures
    such that a similar being can occupy a seed-structure
    which also takes up nutrition from the environement in
    a manner that is consistent with the parent organism.

    these robots have demonstrated neither DIGESTION,
    nor REPRODUCTION, but merely self-assembly.

    this is different than a PLANT -- which given
    only MUD, LIGHT, and WATER can transform that
    mud into FLOWERS -- that is digestion. after
    it has done that, the reproductive phase of
    the plant has already quite different qualities.

    plants are able to seperate out the
    individual mineral qualities it encounters in
    the soil, and include them in their structures.

    but for these robots -- they are not using raw materials
    like WATER, MUD, and LIGHT -- if it were, you could
    stick it into a puddle of mud, add water and light,
    and watch it do its thing -- creating gears and
    generating power for servo motors out of mud, water
    and light.

    the cubes supplied here are already PRE-MANUFACTURED
    (conveniently added into frame for the video). so if
    you wanted to be truthful about the matter -- you would
    have to include all the processes that humans performed
    to get the pre-manufactured cubes into place for the
    self-assembly operation.

    but in the case of reproduction, there are at least two
    stages present which are absent here: it must first draw
    NUTRITION for its activity from the environment and transform
    that into the raw materials for sustaining its activity.

    then, after it can EAT, it goes on to a second activity
    of reproduction (creating another like itself, which can
    also take the raw substance through digestion, and
    sustain itself).

    changing the definition of reproduction
    to include what is actually self-assembly
    does a diservice to clear understanding of
    the phenomenon.

    j.