"fast" FTL travel and Von Neuman machines

[K^2]

A living cell already uses a good chunk of periodic table, including heavy metals. A living cell already has fibers inside that are as strong as carbon fiber. A living cell already has machinery inside it that does repair and delivery of necessary components. mRNA logic is Turing Complete. These are facts. I don't know if you simply opted not to take any courses in cellular biology or slept through them.

Here is a video that demonstrates just a few of the processes in construction, replication, and material delivery inside the cell that we happen to understand. There is a protein there that works as a frigin' forklift. How much more "factory" do you need it to get? And this is just tip of the iceberg. About the only thing you are correct on is that we can't reliably reprogram any of that, because we don't understand it all. Its way more complex than anything we have ever built. It has more moving parts and more complex programming than anything we have ever built. This is precisely what it takes to build a factory that copies itself. And whether we adjust existing ones, or build it from scratch, we'd have to understand that level of complexity. We don't. But of course, there are experts who claim they can do better.

Oh, and if you really insist on burring yourself deeper with your plane/bird analogy, do you know what else jet engine and a mitochondria have in common? They both use a literal mechanical turbine to generate power.

And if you think living cells are incapable of guzzling power, you are absurdly wrong. Living cells have sufficient power generation reserves to cook themselves. The limiting factor is, once again, heat generation and dissipation. And if you've studied anything about cancer cells, you should have some idea of just what sort of reproduction rate living cells are capable of.

Living organisms limit their reproduction and energy consumption so as not to wipe themselves out and go extinct. This is a fundamental limitation for any self-replicating machinery. We can throw living cells into overdrive and cause them to reproduce at far faster rate. It's been done in the lab. There is no limitation of biological system that actually enforces the reproduction rates we see in nature. Faster reproduction is simply not sustainable.

[SomeGuy123]

18 minutes ago, K^2 said:

A living cell already uses a good chunk of periodic table, including heavy metals. A living cell already has fibers inside that are as strong as carbon fiber. A living cell already has machinery inside it that does repair and delivery of necessary components. mRNA logic is Turing Complete. These are facts. I don't know if you simply opted not to take any courses in cellular biology or slept through them.

Like my Russian TA in Cell Biology points out, none of these processes are 100/0% like a properly designed system would be. Everything is floppy and statistical.

You're wrong.  I'm right.  Argument is over.  I'm sorry, but you don't have any clue about what you're talking about.  Scale alone means the laws of physics are different.

You know this, right?  A machine that has more matter in it can sometimes be qualitatively different.  Physics does care about scale.  Nuclear chain reactions don't even function below a certain scale.  In the computational world, a computer with insufficient complexity can't be sentient (inadequate memory to have enough states).  

So when I talk about a hundred ton machine and you talk about a cell, you cannot say that vaguely sorta similar systems are the same.  They aren't.

Edited February 15, 2016 by SomeGuy123

[K^2]

It's floppy and statistical precisely because of the scale. It's called Statistical Mechanics for a reason.

Your entire argument is that complex machinery necessary for a factory style reproduction cannot evolve. A cell is a perfect counterexample. You are retreating into, "Oh, it works slightly differently," without even looking at the fact that every argument you've made about why it can't evolve is perfectly reproduced in the cell. Complexity, check. Self repair, check. Reliance on individual components, check.

You cannot invent a single distinction between a biological system and a factory that would allow for one to evolve and prevent the other from evolving. You keep talking about "dead zones," but it's totally just a buzzword for you that you've picked up and haven't even thought about. Exactly the same "dead zones" should have prevented evolution of Eukaryotes. Do you happen to recall how they managed to evolve these capabilities, at least?

37 minutes ago, SomeGuy123 said:

You're wrong.  I'm right.  Argument is over.

See, this is the kind of attitude that prevents you from actually learning anything. Critical thinking is a key requirement in science. So is making an argument. If you want to simply take that attitude and give up on defending your point, I suggest you give up on your career. I'm nowhere near as stubborn as most of your reviewers are going to be.

 

P.S. I bet I have more publications on cell biology than you do. XD

Edited February 15, 2016 by K^2

[SomeGuy123]

26 minutes ago, K^2 said:

P.S. I bet I have more publications on cell biology than you do. XD

You can be the most cited researcher on the planet.  You're still wrong.  The laws of physics are what determine who is right or not, and physical laws support me and they don't support you.  Period.  I haven't retreated from anything, a structure that is sorta like something but not something is not something.  A campfire isn't a blast furnace. Dr. Drexler is kinda sorta a world authority on the subject, and there's a billion dollars in research funding to support directly his ideas.  Where's your billion dollars in funding?

There's nothing to learn because you're so far wrong there is no information in your posts.  That's the problem.  This would be like a discussion where I'm talking about jet aircraft and you're still talking about the 5 elements and whether or not a balloon covered in animal skin will fly.

Edited February 15, 2016 by SomeGuy123

[K^2]

Do you seriously not see the irony of telling a high energy physicist with experience and an actual publication in cellular biology that he doesn't understand the physics of reproducing machines? This would be appropriate if you were yourself an expert, with tons of expertise in cellular biology. Heck, I would settle for an ambitious undergrad who can construct a coherent argument and do some actual research, cite some papers at least. But you literally have nothing to back your claims other than some popular science literature you've read. If you happen to be right, it's by sheer accident at this point. But no, you have audacity to claim that your position is infallible.

I have offered to argue physics with you. Make your point. I am well versed in Statistical Mechanics of the small and Classical Mechanics of the large. I even happen to be familiar with software involved in actual manufacturing and rapid prototyping, simply because I do my own 3D printing, so I'll happily discuss with you the finer points of tolerances in manufacturing. But you aren't defending your claim. Other than insisting that "this isn't how it works," you've literally made no attempt to actually defend your position.

I've had students like you. They don't last long. You need to revise your attitude. I don't care what you take out of this argument, but you seriously won't make it in academia if you keep this up.

Edited February 15, 2016 by K^2

[magnemoe]

7 hours ago, SomeGuy123 said:

I already gave one.  Let me reiterate.

The factory I'm talking about uses hard carbon or metal components, everything tightly integrated like a watch.  Thousands and thousands of steps are integrated together and the thing is hyperfast.  Pieces of the factory do fail, and digital watchdog systems detect this and order the failed components recycled.

Like this.  

A floppy eukaryotic cell is nothing at all like this.  At all.  Again, it's like the difference between a mitochondrion in a bird and a jet engine.  The parts are different, the principles are different, the energy storage mechanisms are different - the only thing in common is both are combusting hydrocarbons for energy.

The cell is floppy, it won't fail if a single atom gets out of place, it isn't cooled to near cryogenic temperatures, it isn't made of metal and diamond, it doesn't have digital sensors and exact control logic (mRNA regulation is statistical), it isn't in hard vacuum, it can't be intelligently redesigned, it can't operate using most of the elements on the periodic table, it won't have digital error correction between generations to reduce the probability of mutation to zero...

I'm talking about machine phase chemistry.  You're talking about goop in a bag.  There are about alike as jet engines and mitochondria.

And yeah, just like jet engines guzzle hydrocarbon fuel by the ton, nano machinery factory would burn through energy and feedstock at incredibly voracious levels.  They would burn far more energy to, say, make an ingot of steel than a steel forge uses for the same task.  (but the ingot would be perfect).  Which doesn't matter - living cells don't have nuclear reactors or vast arrays of solar panels plugged in to them via power cables...

Also, something else you might have missed : the minimum "replication subunit" of a nanomachinery factory is still a bunch of equipment.  It's a plasma furnace to digest matter.  A bunch of chemical reactors to get it to the atomically pure feedstocks.  Probably multiple stages of filtering.  (all sorts of high end equipment to do that - lasers, calutrons, etc)

There are still 3d printers - they make the bulk stuff like frames and tank walls and casing and things where atomic precision isn't needed.  And then the core machine, the nanofactory, is hundreds of thousands of separate assembly lines that converge on one another. Some assembly stations in the factory can be state adjusted - ON/OFF/A/B - which is how the factory can make multiple outputs.  (different final products have modular components added or missing in sockets on them)

The whole "nanofactory" isn't nano at all, once you include all the assembly lines and all the ports for input gases and coolant and power and all the duplicate backup assembly lines, the thing is desktop printer sized or larger.  Any smaller and it's not functional.

There are then robots as well.  And a control computer.

This whole machine weighs over a hundred tons.  Remove any major part, and it will not replicate itself.  It is too complex for nature to design via evolution, at least not without more time than the sun has left.  It doesn't compete with living cells in the same environment and the "nanomachinery" isn't separate free running cells, everything must be welded down and connected to power leads and be heat sinked...

I think maybe you had some sci fi nanobot the size of a eukaryotic cell roaming around free in mind.  I will agree with you there - the environment at that level doesn't have enough energy to do things this way.  The "nanobot" would never get enough energy to copy itself at any decent rate since it is having to synthesize diamond, etc.  Also, it would just jam and fail since it's outside the vacuum chamber it would be intended to operate in.  So you'd have to make it more flexible to survive in the living biosphere on earth, and after you do all that you end up with something that is marginally better than existing life at best.

Nice, has seen the molecular level 3d printer before but not in this layer of details. It still be far more limited than shown here. Don't mistake me its an interesting way to make micro stuff like cpu. Probably even better on simpler structures, memory solar panels, screens. Add stuff we can not make today like active filters. 
It would also be far more flexible than today fabrics for stuff like this, Add 3d printers and then assembly by robots on top and you have an von-neuman machine 

As you say this is an complex device, it would also not go cancer on its creators, any fail in coding and it would stop, probably do an reset to factory state. 
Fixing this is also fairly simple, the code transferred then making copies of itself is encrypted and packed so any errors will result in junk. You then use multiple copies and error correction to avoid this. 
If its sentinel it might have its own agenda, 
I see self replicating von-neuman probes more useful if you don't have faster than light. If you can jump between star systems star trek style you mostly need them for manufacturing and can control them pretty close but its one of the few ways to explore the galaxy slower than light. 

[problemecium]

I'm all for educated debate, but, um... this thread, in a nutshell:

OP: Science! Let's have an edifying chat about grey goo scenarios in relation to FTL travel!
1: Science science science. Grey goo. Science. Astronomy. Is this working?
2: Science Science Science. Creationists. Science astronomy.
3: CREATIONISTS?!?!?
2: Your an idiot. Go away and never speak again.
3: No ur an idiot! Evolution creationists science research science.
4: FTL is impossible so this thread is dumb.
3: SCIENCE EVOLUTION CREATIONISTS UR STUPID
2: EVOLUTION CREATIONISTS SCIENCE NO UR STUPID
Me: This post.
Vanamonde (in the near future): Thread locked.

To avoid this conclusion, can we move our evolution argument somewhere else and go back to what the poor OP was talking about? No offense meant to anyone in particular, and I left out some posts in my recap, but hopefully we can see the problem here and save the thread before it's too late.

[SomeGuy123]

14 hours ago, K^2 said:

Do you seriously not see the irony of telling a high energy physicist with experience and an actual publication in cellular biology that he doesn't understand the physics of reproducing machines? This would be appropriate if you were yourself an expert, with tons of expertise in cellular biology. Heck, I would settle for an ambitious undergrad who can construct a coherent argument and do some actual research, cite some papers at least. But you literally have nothing to back your claims other than some popular science literature you've read. If you happen to be right, it's by sheer accident at this point. But no, you have audacity to claim that your position is infallible.

I have offered to argue physics with you. Make your point. I am well versed in Statistical Mechanics of the small and Classical Mechanics of the large. I even happen to be familiar with software involved in actual manufacturing and rapid prototyping, simply because I do my own 3D printing, so I'll happily discuss with you the finer points of tolerances in manufacturing. But you aren't defending your claim. Other than insisting that "this isn't how it works," you've literally made no attempt to actually defend your position.

I've had students like you. They don't last long. You need to revise your attitude. I don't care what you take out of this argument, but you seriously won't make it in academia if you keep this up.

Calming the histrionics a little : my argument is 2 fold.  None of your pedigree and none of your arguments has even addressed the topic of my argument.

1.  The vacuum of space, where available resources are a different element mix than the biosphere of Earth and there's a lot more radiation exposure, is a different environment than liquid water + 1 G + rad shielding + a while biosphere.  

If you're really the expert you claim to be, you know that any machine - replicating or not - has to be optimized for a specific environment.

My statement is that if you could make machines that spread across the universe- whether by waiting centuries to travel between stars or some hypothetical instant teleportation that is (probably) impossible - implicitly means the machines spend almost all of their time in the environment that Earth life isn't optimized for.  (or even particularly functional in)

Your statement I'm responding to is " It's called life. It's absurd to think that robots are going to spread more rapidly, or consume more matter than living things, because a self-replicating robot is just another living thing. "

2.  The second topic is that you know damn well, per your admitted pedigree, that out of all possible arrangements of matter that form a "self replicating machine the size of a eukaryotic cell" that has to operate in the same environment that current eukaryotic cells operate in now, evolution did not find the optimal one.  In fact, due to version lock in inflexibility, finite biosphere space, and so forth, we don't know if the current setup is even close to the true theoretical maximum.  

You don't know, I don't know, nobody knows.  

So it's plausible that if you have a machine - an intelligent optimizer, a machine capable of accurately simulating physics to sufficient precision, a machine capable of searching the entire design space of all possible configurations of matter (yeah, you'd need some pretty clever algorithms to winnow this down) - you could beat life at it's own game.  Probability (the fact that evolution has rolled dice and ended up at an arbitrary set of common arrangements of self replicating matter and it cannot investigate other possibilities due to the way the competition works) dictates that a significantly more optimal machine is immensely more probable than not.  

So yes, you probably could, if you had the resources, make a "grey goo" robot that ate the whole biosphere because it is factually faster and more efficient at reproduction than existing systems.  But that wasn't the topic of discussion...

 

 

Edited February 15, 2016 by SomeGuy123

[K^2]

I'll give you plausibility. But that's enough for me to take down your entire argument. It's plausible that extreme FTL method exists, and it's plausible that grey goo or Von Neumann probes with similarly scary reproduction rates can be created. We aren't currently being devoured by infinitely replicating machines, so we can conclude that no civilization in all of space has managed to achieve both. We can also throw in "or was crazy enough to let it loose," but you'd figure there would be at least one Dalek civilization somewhere out there that'd be bent on building berserker probes.

So we conclude that with very high certainty, one or the other is not achievable. And I could leave it at there, but I'm going to propose one more thing.

Suppose that it was possible for a reasonably intelligent civilization to construct such self-replicating machines. Say, Humans at some point later in their development. There are, by all indications, billions of worlds in our galaxy alone that would have supported some sort of civilization at some point between galaxy's formation and now. Many of these are completely gone now, along with their stars. Some might still be around. And it'd only take a million years to cross galaxy end to end at mere 0.1c.

If you can figure out why you're not being devoured by some sort of grey goo made by some civilization in Milky Way a billion years ago, I'm sure you'll quickly find that reason applicable to why you wouldn't need to worry about a civilization with super FTL drives several superclusters away from here.

[SomeGuy123]

8 minutes ago, K^2 said:

If you can figure out why you're not being devoured by some sort of grey goo made by some civilization in Milky Way a billion years ago, I'm sure you'll quickly find that reason applicable to why you wouldn't need to worry about a civilization with super FTL drives several superclusters away from here.

I agree with you.  To me, since I can draw a paper drawing of a ship the size of a chunk of a planet (so you can't argue that it doesn't have enough biosphere to be closed loop) and stick antimatter rockets on the back, and I know you could cram in enough factories to make the ship again, well, that's a von neuman machine.  A stupendously slow and inefficient one but exponential growth is still exponential.

So maybe interstellar travel at anything approaching a reasonable speed (0.1% C or something) is impossible.  Or, umm, something really unusual.

None of those explanations make any sense.  What does make sense should be right up your alley.  

Evolution is a rat race that ends up with the competing organisms ascending to local maxima.  As long as the environment is unchanged, any organism that tries to leave the peak of a local maxima gets out-competed.  

So if earth had no mass extinctions and no land, all water, logically it would be still nothing but various forms of photosynthetic bacteria.  Maybe simple multicellular organisms, maybe not.

Anything that attempts anything new (aka I mean mutations make it different) is sub optimal and it gets eaten over time.

So it took about 3 billion years, 1/4 the life of the universe to reach this point. And maybe the cosmic lottery had to be arranged just right or you end up with nothing but a sea of cyanobacteria.  

That makes sense because it explains the data and it reflects the reality that evolution stalls out as an algorithm.  What do you think?

 

 

[fairytalefox]

16 minutes ago, K^2 said:

It's plausible that extreme FTL method exists

Can you elaborate please? What, besides optimism and other personal traits, could make someone think so?

[Stargate525]

On 2/14/2016 at 8:01 PM, SomeGuy123 said:

     Observation : the visible universe seen by telescopes does not appear to be majorly edited by intelligent life.

Hypothesis : "fast" FTL travel is impossible.  The reason is simple.  In science fiction, it is common for there to be no ultimate speed limit.  More and more advanced alien races can get around quicker and quicker.  N00bs like humanity might take a few days to reach another star (like Starfleet), but there are methods that are faster and faster, to the point of reaching other galaxies in hours.  

What would be the consequence if this actually is possible?  (never mind existing knowledge of physics, let's just say there is an exploit not yet found that lets you basically teleport anywhere in the universe instantly)

Well, all it takes is one species with the ability to (1) teleport around near instantly (2) consume arbitrary solid matter to make self replicating robots.

Basically, once they have the technology for one and two, ZOOMP, whole universe is converted.  We as a species never come to exist because this happened long ago.  Ergo, since humans do exist, it's probably not possible to do (1).  (we basically already can do (2) as we ourselves are such replicating robots.  We just need some tools we already know how to make to let us turn arbitrary chunks of planets and asteroids into things we can eat and live in)

Counter-conclusions:
-Fast FTL is possible, but has not been abused in the method you state, or attempts to do such have been otherwise curtailed.
-Fast FTL is possible, and the resulting galaxy/universe is what a post Neuman machine environment looks like.
-Fast FTL is possible, but there is a second higher speed limit we have yet to determine.
-Fast FTL is possible, but we are the first occurrence of intelligent life within range.

You are making a number of false assumptions which do not logically follow from the observation. Your post is akin to a man spying an island from his shore from afar and stating "This land does not appear to be majorly edited by intelligent life. Ergo, it is impossible to reach that island, as any life over there would have conquered us long ago."

[SomeGuy123]

29 minutes ago, Stargate525 said:

You are making a number of false assumptions which do not logically follow from the observation. Your post is akin to a man spying an island from his shore from afar and stating "This land does not appear to be majorly edited by intelligent life. Ergo, it is impossible to reach that island, as any life over there would have conquered us long ago."

I'm not concluding anything, just pointing out that if all the islands you can see look barren and deserted, and you don't actually have boats yet, though as a feat of epic accomplishment you managed to just barely dip your toes in the water and not die instantly, and your ancestors actually managed to make a tiny float and retrieve a sample from a piece of debris nearby...you might wonder what's going on.  Maybe the boat building project is a dead end.

[K^2]

1 hour ago, SomeGuy123 said:

None of those explanations make any sense.  What does make sense should be right up your alley.  

Evolution is a rat race that ends up with the competing organisms ascending to local maxima.  As long as the environment is unchanged, any organism that tries to leave the peak of a local maxima gets out-competed.  

[...]

And maybe the cosmic lottery had to be arranged just right or you end up with nothing but a sea of cyanobacteria.

I don't think it's humans that are impossibly unlikely. If we didn't have true Eukaryotes, we'd have complex life made up of symbiotic colonies of simpler stuff. Either way, as soon as they figure out sexual reproduction, whether on cellular level or colony level, it's kind of downhill from there.

I think it's simpler. I think any self-replicating machine will eventually fall into the same trap. A tiny error in programming that managed to slip all of your error correction codes could give a specific machine a tiny bit of advantage in one particular environment. No, it's no longer competitive in all environments, the way its creators envisioned, but it's going to outnumber "healthy" machines in that one specific environment. From there, it starts to adapt. Sooner or later, it will drop any restrictions on mutation that were supposed to prevent it from doing so, and be capable of out-adapt in any particular environment. And then we're back to having plain old life, which will compete with itself and settle into a niche.

It's Red Queen and Prisoners' Dilemma rolled into one package with Chaos Theory. There is only one way that can go.

1 hour ago, fairytalefox said:

Can you elaborate please? What, besides optimism and other personal traits, could make someone think so?

Basic understanding of field theory and differential manifolds, preferably with focus on GR, QFT, and their dualities.

[magnemoe]

1 hour ago, Stargate525 said:

Counter-conclusions:
-Fast FTL is possible, but has not been abused in the method you state, or attempts to do such have been otherwise curtailed.
-Fast FTL is possible, and the resulting galaxy/universe is what a post Neuman machine environment looks like.
-Fast FTL is possible, but there is a second higher speed limit we have yet to determine.
-Fast FTL is possible, but we are the first occurrence of intelligent life within range.

You are making a number of false assumptions which do not logically follow from the observation. Your post is akin to a man spying an island from his shore from afar and stating "This land does not appear to be majorly edited by intelligent life. Ergo, it is impossible to reach that island, as any life over there would have conquered us long ago."

More relevant, we agreed that an space based von-neuman machine would be decent sized, think ISS not an bacteria. Perhaps it could be made as small as an car. However it might be an lack of need for this small size with FTL.
Only way an von-neuman probe goes wild is either rogue AI, ill intend by the ones who deploy it or high level stupidity. 
Without FTL you are likely to use von-neuman probes for exploring an building up infrastructure for the later manned starships, it has to be able to do interstelar travel, reproduce and make decisions itself. 
If it goes rogue it might operate for hundreds of years before somebody find out and you might need 1000 years to reach it. 
Just an radio signal to make it stop will take an long time. 

With FTL you are more likely to use an Von-neuman machine to start factories if you use them at all. 
An von neuman machine in reproduction mode will be far slower than mass production. An factory might use all the features an von neuman machine uses where fitting but is streamlined to produce one thing only in volume. 
Now if an von-neuman machine goes rogue it will be stopped fast, that is unless it build an FTL engine fast and try to run. 
It will be checked regularly and is not designed to run unattended for a long time but deployed for specific tasks
In this setting it will be in war with an interstellar civilization who will outproduce it an billion times and can also travel between stat systems, 
Note that this also hold true for an robot civilization. 

[Stargate525]

44 minutes ago, magnemoe said:

More relevant, we agreed that an space based von-neuman machine would be decent sized, think ISS not an bacteria...

...Note that this also hold true for an robot civilization. 

A grey goo scenario is a cancer of a galaxy, almost literally. Unchecked, improper growth. Any sane society which detects something of this sort would immediately wage war upon it in an attempt to check or at least control it. If it is intelligent, it could very well decide to ignore significant gravity wells and potential annoying life, contenting itself with taking the rest of the loose matter in the galaxy. There is no evidence against the hypothesis that we are IN such a galaxy, and the neumans sit dormant in asteroid belts and trans-newtonian orbits, dark to our methods of detection.

 

2 hours ago, SomeGuy123 said:

I'm not concluding anything, just pointing out that if all the islands you can see look barren and deserted, and you don't actually have boats yet, though as a feat of epic accomplishment you managed to just barely dip your toes in the water and not die instantly, and your ancestors actually managed to make a tiny float and retrieve a sample from a piece of debris nearby...you might wonder what's going on.  Maybe the boat building project is a dead end.

Which is a fine conclusion to make (and it IS a conclusion that you're making), just one supported by flimsy evidence. We simply do not have enough resolution or sample size to conclude what you are without taking a large number of things on faith.

And let's check some things here. You never said barren and deserted. You said not majorly edited by intelligent life. Besides the anomalous oxygen content of our atmosphere, there is nothing detectable at the range-resolution we're currently looking that would posit our OWN existence. To go back to the island analogy, the only sign of other cities we can see is bonfire smoke. It is simpler to conclude that there are a) no other people on the islands at ALL, despite the lush environs, b) they don't use bonfires and we can't see their tents, or c) we're too busy looking at the islands and aren't looking for guys in canoes.

[SomeGuy123]

2 hours ago, Stargate525 said:

And let's check some things here. You never said barren and deserted. You said not majorly edited by intelligent life. Besides the anomalous oxygen content of our atmosphere, there is nothing detectable at the range-resolution we're currently looking that would posit our OWN existence. To go back to the island analogy, the only sign of other cities we can see is bonfire smoke. It is simpler to conclude that there are a) no other people on the islands at ALL, despite the lush environs, b) they don't use bonfires and we can't see their tents, or c) we're too busy looking at the islands and aren't looking for guys in canoes.

The hole here in your thinking is this.  

Neumanns seem virtually certain to work.  We're examples of them, we see them everywhere, we can easily plan them on paper even though we lack the prerequisite techs in 2016 (nanoscale manufactories, sentient computers).

You basically have to believe in magic to come to a rational conclusion that they don't work.  (sure, until we actually have them running you can cast doubt but these doubts aren't very credible)

So once we have such technology, some of us will have different ideas on how to use it.  All it takes is a faction of us deciding to let em loose, perhaps riding along by brain uploads, and the rest is just a simple inevitable result of unstoppable exponential growth combined with natural selection.

Warfare to "stop" them is silly and fantasy thinking.  You can't, all you can do is build your own and try to claim some stars before they grab them all.  Any plausible starship is so insanely vulnerable and fragile that it's a "defenders are god" kind of military scenario - anyone who has full control of a star system will have it forever. 

So by this theory, the fact that we don't see shadows from dyson swarms at every star in view implies that there aren't any intelligent beings with science at all, anywhere, within the area of the universe we can see.  (because it took us under 300 years to go from Newton's scientific method to now, and we're probably less than a century from having straight up sentient von neumann machines.  This seems like a reasonable estimate to me now that AI research is actually getting solid, respectable results and we are actually spending money to scan human brains at more detailed levels so we can steal the patterns it uses).  

 

Edited February 16, 2016 by SomeGuy123

[magnemoe]

6 hours ago, SomeGuy123 said:

The hole here in your thinking is this.  

Neumanns seem virtually certain to work.  We're examples of them, we see them everywhere, we can easily plan them on paper even though we lack the prerequisite techs in 2016 (nanoscale manufactories, sentient computers).

You basically have to believe in magic to come to a rational conclusion that they don't work.  (sure, until we actually have them running you can cast doubt but these doubts aren't very credible)

So once we have such technology, some of us will have different ideas on how to use it.  All it takes is a faction of us deciding to let em loose, perhaps riding along by brain uploads, and the rest is just a simple inevitable result of unstoppable exponential growth combined with natural selection.

Warfare to "stop" them is silly and fantasy thinking.  You can't, all you can do is build your own and try to claim some stars before they grab them all.  Any plausible starship is so insanely vulnerable and fragile that it's a "defenders are god" kind of military scenario - anyone who has full control of a star system will have it forever. 

So by this theory, the fact that we don't see shadows from dyson swarms at every star in view implies that there aren't any intelligent beings with science at all, anywhere, within the area of the universe we can see.  (because it took us under 300 years to go from Newton's scientific method to now, and we're probably less than a century from having straight up sentient von neumann machines.  This seems like a reasonable estimate to me now that AI research is actually getting solid, respectable results and we are actually spending money to scan human brains at more detailed levels so we can steal the patterns it uses).  

 

An von-neuman machine is plausible. We do not know how much it can be scaled down. Worse case it would require something the size of an generation ship. 

With easy FTL interstellar warfare is fairly easy. Problem is the size of the universe making it fairly easy to hide, however large scale energy use like rocket engines are easy to spot inside an solar system, Have probes jumping around looking then take some batleships out of warp next to enemy. 
Without FTL interstellar warfare is implausible hard. 

The assumatation that any cilvilisation will generate rogue von-neuman machines looks a lot like the common solution of the drake equation back around 1980, any civilization will nuke it self after short time, going back 10 years and I guess it was it would run out of resources. 

[magnemoe]

9 hours ago, Stargate525 said:

A grey goo scenario is a cancer of a galaxy, almost literally. Unchecked, improper growth. Any sane society which detects something of this sort would immediately wage war upon it in an attempt to check or at least control it. If it is intelligent, it could very well decide to ignore significant gravity wells and potential annoying life, contenting itself with taking the rest of the loose matter in the galaxy. There is no evidence against the hypothesis that we are IN such a galaxy, and the neumans sit dormant in asteroid belts and trans-newtonian orbits, dark to our methods of detection.

Grey goo itself will not be more than an planetary problem, it don't have much dV. it will also be limited by energy and raw materials. 
Cancer works as it lives inside an body with lots of resources, it don't survive in the wild. 

here the issue is an rogue self replicating factory or spaceship with its own agenda. One who is simply corrupted would be of limited danger. 

[Stargate525]

8 hours ago, SomeGuy123 said:

The hole here in your thinking is this.  

Neumanns seem virtually certain to work.  We're examples of them, we see them everywhere, we can easily plan them on paper even though we lack the prerequisite techs in 2016 (nanoscale manufactories, sentient computers).

You basically have to believe in magic to come to a rational conclusion that they don't work.  (sure, until we actually have them running you can cast doubt but these doubts aren't very credible)

So once we have such technology, some of us will have different ideas on how to use it.  All it takes is a faction of us deciding to let em loose, perhaps riding along by brain uploads, and the rest is just a simple inevitable result of unstoppable exponential growth combined with natural selection. 

 

By that logic, there should be a single species on this planet. If natural selection impacts these devices, then there will at some point be two species of Neumans. They would compete. Bacteria replicate exponentially, and we can still successfully stop those.

[fredinno]

 

 

17 hours ago, K^2 said:

I'll give you plausibility. But that's enough for me to take down your entire argument. It's plausible that extreme FTL method exists, and it's plausible that grey goo or Von Neumann probes with similarly scary reproduction rates can be created. We aren't currently being devoured by infinitely replicating machines, so we can conclude that no civilization in all of space has managed to achieve both. We can also throw in "or was crazy enough to let it loose," but you'd figure there would be at least one Dalek civilization somewhere out there that'd be bent on building berserker probes.

So we conclude that with very high certainty, one or the other is not achievable. And I could leave it at there, but I'm going to propose one more thing.

Suppose that it was possible for a reasonably intelligent civilization to construct such self-replicating machines. Say, Humans at some point later in their development. There are, by all indications, billions of worlds in our galaxy alone that would have supported some sort of civilization at some point between galaxy's formation and now. Many of these are completely gone now, along with their stars. Some might still be around. And it'd only take a million years to cross galaxy end to end at mere 0.1c.

If you can figure out why you're not being devoured by some sort of grey goo made by some civilization in Milky Way a billion years ago, I'm sure you'll quickly find that reason applicable to why you wouldn't need to worry about a civilization with super FTL drives several superclusters away from here.

Von Neumann machines can spread without FTL- just give them time.

[K^2]

4 hours ago, fredinno said:

Von Neumann machines can spread without FTL- just give them time.

That is paragraph 3 of the text you just quoted.