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Constructor Theory Solves the Riddle of Life
- pizza 11y agoSome reading that disagrees with Constructor Theory: http://motls.blogspot.com/2014/05/constructor-theory-deutsch-and-marletto.html http://motls.blogspot.com/2014/05/constructor-theory-deutsch... Looking forward to reading comments that disagree with this disagreement.
- Xcelerate 11y agoLubos is normally a little too ornery for me, but I thoroughly enjoyed that post. Constructor theory (or at least that article about it), seems like superficial nonsense. Kind of in the same way that programming languages become bloated with concepts like "Object Factory Factories" and "Singletons" and delegates, etc.
- jerf 11y agoWell... it may solve the riddle of life, but that article sure doesn't explain how at all. This is a criticism of the article, not the theory, as my point is that the article is not describing this well enough to be critical of a theory that I still don't have any idea about.
- scrumper 11y agoI wasn't left that much the wiser after reading this either. In short, I think "constructor", "recipe", "knowledge" are some pretty heady concepts which could use a lot more explanation. I think what it's trying to say is that constructors are resilient (i.e. long lived, through virtue of replication) 'structures' expressed in matter capable of stably holding and repeatably acting on digital information. And once you have a basic constructor, assemblages of these can provide successively higher levels of organizational power. Their digitally error-corrected resilience differentiates them from flash-in-the-pan analog chemistry, and once you have that longevity of structure you can start to have life. I think. I don't know. I mean, yes, intuitively, life as an emergent property of recursive layers of self-organizing structures makes more sense than life as the continuation of a random walk through chemistry, but whatever constructor theory is, it's not deeply explained here. What are its implications? How does it actually compare to alternative theories?
- powera 11y agoThis article begs the question on "Biological replication and self‑reproduction are in fact such stupendously well‑orchestrated physical transformations that one must explain how they are possible under the simple, no‑design laws of physics such as ours. This additional explanation, which was not included in the theory of evolution, is essential for that theory to properly explain how living things arise without intentional design – to close the explanatory gap." From my point of view, chemistry more or less explains how cells work, and we don't need a quasi-platonic explanation of how the universe is designed to allow for a grass-eating goat machine to explain this at all.
- o_nate 11y agoExplaining how a cell works is not the same as explaining how cells first came to exist. Once a cell exists, given certain conditions, it can replicate itself - we can explain each step in the process with reference to laws of chemistry. However, a different question is: How did this process get started? That's the question this article is addressing.
- trhway 11y ago>Explaining how a cell works is not the same as explaining how cells first came to exist to me it became much clearer when i read somewhere (just dont' remember where) along these lines - imagine a "stick" shaped pretty simple organic molecules with one end being hydrophobic and the other hydrophilic (there are a bunch of such molecules known in organic chemistry). Having a soup of those molecules in water, some of the molecules would naturally clump together with hydrophilic ends outside and hydrophobic ends inside - kind of a small bubble. Now if on contact of a bubble with another molecule, the molecule is added into the bubble (similar like a bunch of magnets clumped together "assimilate" another magnet piece correctly orienting it), the bubble gets bigger and at some point it would naturally splits into 2 smaller bubbles (surface tension, etc...) and each bubble would continue the "assimilation"/growth and division in their turn as long as there are such molecules around... Of course it isn't even "pre-cell", it is just showing how natural physics laws can drive the initial pre-life stages.
- mkehrt 11y agoThis...seems like nonsensical pseudoscience.
- wbhart 11y agoAfter reading the article I was left with the distinct impression that "constructor" is a name for something they suppose must exist to solve their problems and that the mere act of giving it a technical sounding name allows them to say they've solved the problem of the origin of life, since now they may say "constructor theory solves that problem".
- Nevermark 11y agoAnd its not even an original mistake. Our ancestors also used words (like "god") to answer (i.e. stop asking) questions about the origin of life. But I for one look forward to worshiping the Great Constructor.
- cronjobber 11y agoNice theory. Fly in the ointment: Our ancestors didn't stop asking, quite obviously, given that we ended up here.
- Nevermark 11y agoActually a lot of ancestors did stop asking. I think that is established fact, not theory, as even today it is easy to find people who disbelieve even basic science when it contradicts a religious view. But fortunately, as you point out, not everyone stops asking questions.
- jfoutz 11y agoI think it's a little more subtle. A constructor is like a program. In this case, the rules of the language are physics itself. We're familiar with writing simple programs in C. We can imagine programs, like the halting problem solver. It turns out that program can't exist, but you kind of have to think about it for a while to understand why. A constructor (as i understand it) is sort of hand rolled assembly (matter) running right on physics. Perhaps there are space unicorns on the dark side of the moon. We can imagine that. It's not really clear if physics actually allows that though. My gut says no, but the rules of the game, much like the rules of the language may allow such a collection of matter to exist. I mean, quines are pretty weird. I wouldn't have thought that was even possible.
- daveloyall 11y agoI can't follow the article. I'll assume it means this: //Old theory u = new Universe(); //TODO: populate... ... //New theory r1 = Replicator.getInstance(); r2 = Replicator.getInstance(); r3 = Replicator.getInstance(); u = new Universe(r1,r2,r3); :)
- metaphorical 11y agoCarl Sagan once said: "If you want an apple pie from scratch, you must first invent the universe". As I understand it from this article, it is saying: "Once you invent the universe, then an apple pie will exist... given enough time." ?
- Nevermark 11y ago"Once you invent the universe, then an apple pie will exist... given enough time." An interesting conjecture but not exactly provable! I assert that a universe is a necessary but not sufficient condition for apple pies.
- Yen 11y agoThe article is a bit hard to parse, here's my take on it Given a universe, in which the exact arrangement of particles that make up an apple pie is not physically impossible, it is physically possible for an apple pie to arise through the evolution of the universe, without requiring 'outside input'. (i.e., design or influence by some entity outside the universe). Furthermore, while it would be stupendously unlikely for an apple pie to arise completely by chance (imagine the odds of all the right atoms just happening to collide in the right way at the right time), it's not nearly as unlikely that some kind of self-replicator should arise, and this self-replicator could eventually generate an apple pie, or something of similar complexity.
- dangerlibrary 11y agoPrevious conception: We accept that the laws of physics must be compatible with the observation X (in the article's case, life), but they do not explain why X exists. Constructor Theory: All things not explicitly forbidden by the laws of physics can exist. The answer to "Why does life exist?" is: "because the laws of physics do not explicitly prevent it." Seems like an interesting take. I'm not convinced that it's at all useful, but it's not obviously flawed or vacuous. Sidenote: I've never felt that the existence of life was as mystifying a physical problem as the existence of black holes, or expanding space time, or stars. Why people are mystified by life but blithely accept the existence of distant fusion reactors the size of our solar system is beyond me.
- white-flame 11y ago"The laws of physics do not explicitly prevent space unicorns living on the far side of the moon." Yeah, I don't see this as all that useful, either. It also still doesn't in any way advance discovering what process brought things into being, it only accepts that it happened, which everybody already accepted.
- dangerlibrary 11y agoWe kind of already understand the physical processes that brought things into being, though. A mix of random chance and physical laws happened to create the right environment for hydrogen and oxygen and carbon and nitrogen to exist in the same place at stable temperatures for a couple billion years, and we got life. The question is "can we accept the fact that this process took place without being designed." Constructor theory says, in short: "Yep. We can also accept the existence of space unicorns, for a physically possible definition thereof. Probably not on the far side of the moon though, since we've been there and would've seen them."
- qq66 11y ago>" A mix of random chance and physical laws happened to create the right environment for hydrogen and oxygen and carbon and nitrogen to exist in the same place at stable temperatures for a couple billion years, and we got life." That sentence just skipped over the most important part of the whole question! :)
- agentsmith 11y agoAnyone else come away with the feeling that the research, the 'discovery' and the article wouldn't exist if there weren't very uncomfortable atheists behind it all?
- panic 11y agoA scientific theory has to do more than explain existing phenomena: it has to make predictions which can be tested. What are some testable predictions of constructor theory?
- statik_42 11y agoThis seems almost like a scientific way of stating Murphy's law with an addendum: anything that can happen, will happen..eventually.
- contravariant 11y agoI'm not too impressed with this 'constructor theory' so far. For instance they claim: >In constructor theory, physical laws are formulated only in terms of which tasks are possible (with arbitrarily high accuracy, reliability, and repeatability), and which are impossible, and why – as opposed to what happens, and what does not happen, given dynamical laws and initial conditions. A task is impossible if there is a law of physics that forbids it. Otherwise, it is possible – which means that a constructor for that task – an object that causes the task to occur and retains the ability to cause it again – can be approximated arbitrarily well in reality. This seems to be false, as there is no physical law preventing entropy from decreasing but there is a physical law which prevents the existence of a 'constructor' capable of decreasing entropy. >Moreover, it is a fundamental idea of constructor theory that any transformation that is not forbidden by the laws of physics can be achieved given the requisite knowledge. There is no third possibility: either the laws of physics forbid it, or it is achievable. Either they are saying something is achievable if and only if there is a constructor for it, which is false (see previous point), or they are claiming something is achievable if and only if the laws of physics don't forbid it, which makes this 'fundamental idea' vacuous.
- AnimalMuppet 11y agoIf you can build a constructor for it, it's possible. OK, I'm fine with that. If you know it's impossible, then you can't build a constructor for it. Also fine. But where it sounds like this is going is: If you don't know it's impossible, then it must be possible to build a constructor for it. That assumes that everything that we don't currently know is impossible must be possible. That's... quite an assumption. Worse, that assumption is swept under the rug rather than explicitly stated. Or I could be misjudging their position...
- contravariant 11y agoI think there's also a (again silent) assumption that a constructor can be constructed, which is again non-trivial, and actually seems to be false. And if it is false then that seems like a major flaw, at least I don't really see how a non-constructable constructor is more convenient than the physical laws it is supposed to represent. I also suspect you'll encounter something like the halting problem when trying to figure out which constructors aren't constructable. At worst you'll encounter constructors where this question is unanswerable (e.g. can you construct a constructor, which constructs all constructable constructors that can't construct themselves?).
- hyperion2010 11y agoUnfortunately this seems like a rather weak tool for addressing the issue, we have had conceptually similar tools (though not attempt has really been made to formalize them) for a long time, and many border on the anthropic principle. The reason for the weakness is that there is no guidance for how one is to go about testing whether some constructor actively violates a physical law. In addition this doesn't at all help us delimit the space of all possible constructors. Fundamentally the issue is that constructor theory seems to require us to write down every possible constructor and gives us no way to validate whether they will work, not particularly useful from a theoretical perspective since it is essentially equivalent to having to do an exhaustive search of the space. True, but tautological and rather useless since it doesn't provide any insight into the relative importance of initial conditions (or previous history) and the fundamental forces in delimiting what is possible in any given universe. We want to be able to describe the probabilities of any particular configuration of matter coming to be at some point in time in the universe as a function of the initial conditions and the forces that govern it (statmech can sort of do this for simple systems). This simply assigns probability 1 to everything and leaves as an exercises for the reader how to check whether such assignments are consistent with the laws of nature.
- jheriko 11y ago> In short, the theory presupposes the possibility of certain accurate physical transformations, and these are just what no-design laws of physics fail to provide in their starter kit. this statement is strictly untrue. it seems to assume that this behaviour is not going to be selected for, when very trivially it is... natural selection isn't special to life... it applies to everything, again for obvious reasons. its a very, very simple consequence of existence. those things that survive longest survive longest. its so simple its hard to explain. its no more complicated than the action of a sieve, which stops clumps from going through due to physical constraint - a form of natural selection.