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When Does the Universe Compute?

timothy posted about 9 months ago | from the mice-were-quite-clear-about-this dept.

Math 182

KentuckyFC writes "The idea that every physical event is a computation has spread like wildfire through science. That has triggered an unprecedented interest in unconventional computing such as quantum computing, DNA computing and even the ability of a single-celled organism, called slime mold, to solve mazes. However, that may need to change now that physicists have worked out a formal way of distinguishing between systems that compute and those that don't. One key is the ability to encode and decode information. 'Without the encode and decode steps, there is no computation; there is simply a physical system undergoing evolution,' they say. That means computers must be engineered systems based on well understood laws of physics that can be used to predict the outcome of an abstract evolution. So slime mold fails the test while most forms of quantum computation pass."

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182 comments

Joke of the Day (5, Funny)

Anonymous Coward | about 9 months ago | (#45072513)

"I'll get it," a wife said to her husband as the phone rang.
On the line a pervert, breathing heavily, said, "I bet you have a tight asshole with no hair."
"Yes," she responded. "He's sitting next to me watching TV."

Re:Joke of the Day (4, Funny)

Hognoxious (631665) | about 9 months ago | (#45072639)

More entertaining than the article, and contained more useful information.

Excellent blog, would buy again!

Re:Joke of the Day (2)

oldhack (1037484) | about 9 months ago | (#45073001)

You know, this AC first-post joke is likely the best that can be salvaged from this bullshit "story".

Recursion (-1)

Anonymous Coward | about 9 months ago | (#45072587)

Jacking off is the universal computing action of downloading porn for someone else in a galaxy far far away..

Will it blend? (1)

marcello_dl (667940) | about 9 months ago | (#45072599)

Before we go into philosophy, I warn that being a computation is different from "being the result of a computation". The mold can be simulated.

Re:Will it blend? (2)

ackthpt (218170) | about 9 months ago | (#45072789)

Psst! It's an Analog Computer, they're way faster and more flexible than digital ones, but don't tell anyone or I'll be modded down into oblivion.

I don't think encoding/decoding are fundamental (2, Interesting)

presidenteloco (659168) | about 9 months ago | (#45072605)

Why can we not think of the information as being embodied in "some aspect or other of" the matter and energy undergoing evolution. It is only some observer that needs to see the information as having been encoded or decoded.

Metrics of computations, or measurements of information flows, may be a productive way of describing (and predicting) complex physical evolutions, regardless of whether the physical system itself is identifiably encoding and decoding information explicitly. You just have to establish your own observer convention for how you think the information is represented in the matter and energy under discussion, or you can even just think about "the maximum amount of information" that could be contained in that matter/energy/spacetime region, and the maximum possible amount of information flow there.

Re:I don't think encoding/decoding are fundamental (2)

Xaedalus (1192463) | about 9 months ago | (#45072683)

If I understand your argument, you're speculating that the universe is a pantheistic, evolving computation seeking entropy?

Re:I don't think encoding/decoding are fundamental (0)

Codifex Maximus (639) | about 9 months ago | (#45073083)

I used to adhere to the Theory of Entropy. Made sense at the time kinda like the flat world and Earth being the center of everything.

With a greater understanding of Physics and Cosmology, I've come to realize that the Earth is not flat nor the center of everything. With the realization that Energy is neither created nor destroyed only converted - the Theory of Entropy is disrupted in my mind and therefore proven false.

Now, discounting Entropy doesn't mean I deny that systems have a tendency to reach a Steady State where a perceived equilibrium has been established.

Re:I don't think encoding/decoding are fundamental (2)

Belial6 (794905) | about 9 months ago | (#45073339)

I had this argument in another thread just yesterday. The laws of thermodynamics are obviously wrong. Wrong in the same way that Newtonian physics is wrong. Meaning that it is close enough for anything I will ever get my hands on, but that it clearly does not explain everything that is happening, and it is clearly violated at some point.

Re:I don't think encoding/decoding are fundamental (2, Insightful)

HybridST (894157) | about 9 months ago | (#45073635)

When thermodynamics is wrong, you've missed something.

Re:I don't think encoding/decoding are fundamental (0)

Anonymous Coward | about 9 months ago | (#45074441)

It's only statistical. It doesn't capture what's really going on. See the Fluctuation theorem.Entropy is not bad, we zip files creating more entropy to send them faster. Disorder is not bad, a lot of humor relies on "you didn't see that coming".

Re:I don't think encoding/decoding are fundamental (1)

Anonymous Coward | about 9 months ago | (#45074417)

Thermodynamics is wrong? Have you found systems A, B, and C where A and B have the same temperature, B and C have the same temperature, but A and C don't? (That would mean the zeroth law is wrong.) Have you found a violation of conservation of energy? (That's the first law.) Has someone built an engine that can extract work from a single thermal reservoir? (That's the second law.) Do you know of a crystal at absolute zero with nonzero entropy? (That's the third law.)

I understand that scientific theories are usually approximations, but you're saying that thermodynamics is obviously wrong, and as a student of thermodynamics I would be very interested to hear your obvious argument.

Re:I don't think encoding/decoding are fundamental (0)

Anonymous Coward | about 9 months ago | (#45073979)

Well, I advanced through all of those stages of thought and am currently three steps ahead, so you should just abandon your current theories that improve on the backward theories pervasive among scientists who claim to study this stuff.

Re:I don't think encoding/decoding are fundamental (3, Insightful)

Hatta (162192) | about 9 months ago | (#45072717)

We only don't see the encoding and decoding steps because we are inside the system that is doing the computation. If the universe were a simulation, those inside the simulation would see a ball trace a parabola with no encoding or decoding steps. Those who designed the simulation would be well aware of those steps.

Re:I don't think encoding/decoding are fundamental (1)

camperdave (969942) | about 9 months ago | (#45073091)

Balls don't trace parabolas. They trace ellipses where one of the focal points is the center of mass of the Earth. In order to trace a parabola, the ball would have to be travelling at around 11.2 km/s

Re:I don't think encoding/decoding are fundamental (4, Funny)

Ultra64 (318705) | about 9 months ago | (#45073411)

Balls don't trace parabolas.

Maybe not *your* balls.

Re:I don't think encoding/decoding are fundamental (1)

K. S. Kyosuke (729550) | about 9 months ago | (#45074015)

The relative error of a common ball's trajectory, thrown at some random angle at speed common for a human arm, barring the aerodynamic drag, with regards to its actual trajectory, is roughly comparable to the relative error of your "11.2 km/s" with regards to actual local parabolic speed near Earth's surface.

Re:I don't think encoding/decoding are fundamental (0)

Anonymous Coward | about 9 months ago | (#45074311)

dude, throw a ball in the air it traces (pretty close to) a parabola.
y=yo + Vot - 1/2 g T ^2
i think you are putting a ball in orbit.

Re:I don't think encoding/decoding are fundamental (0)

Anonymous Coward | about 9 months ago | (#45074693)

Any object that is falling at a speed less than escape velocity is in an "orbit." It's just that when a person throws a ball, usually that orbit intersects the surface of the Earth.

Re:I don't think encoding/decoding are fundamental (0)

Anonymous Coward | about 9 months ago | (#45073451)

Those who designed the simulation

I know you meant this as an illustration, but I think it illuminates the flawed reasoning here. The ball's path is emergent from the rules of the simulation, there need not be any analytical solution or "designers". This is still computation by my definition.

Re:I don't think encoding/decoding are fundamental (1)

Hatta (162192) | about 9 months ago | (#45073705)

Right, the "simulation" could be any algorithm, there needent be designers at all. We could all be living in the 10^10^10^10th iteration of Wolfram's Rule 30.

Re:I don't think encoding/decoding are fundamental (0)

Anonymous Coward | about 9 months ago | (#45074211)

Since the designer of Wolfram's Rule 30 is Stephen Wolfram, I'm very confused by what you're trying to say.

Re:I don't think encoding/decoding are fundamental (1)

Hatta (162192) | about 9 months ago | (#45074405)

One could easily argue that those rules were discovered, not designed. All Wolfram really did was design a numbering system.

Re:I don't think encoding/decoding are fundamental (0)

Anonymous Coward | about 9 months ago | (#45073373)

Why can we not think of the information as being embodied in "some aspect or other of" the matter and energy undergoing evolution. It is only some observer that needs to see the information as having been encoded or decoded.

Sure, you can just sit on your ass forever while waiting for a system that happens to model the calculation you want and happens to be in the right state to match the initial conditions you wanted happens to fall into your lap. Have fun with that.

Re:I don't think encoding/decoding are fundamental (1)

Artifakt (700173) | about 9 months ago | (#45073599)

When you try to define an observer in Physics, you run into a property of Quantum Mechanics. There, an observer is, for example, any outside particle that becomes involved in a state vector. When the state vector begins to impact what the particle is doing, that "collapses the vector", and the quantum state, which is until then is theoretically only a probablity, becomes an actual event, from the 'perspective' of that particle. You can also describe this process in terms of fields instead of particles, which still has much the same implications. Either way, you get an infinte regress, as it is possible to define a new state vector that includes that particle, and collapse that vector as it interacts with another particle, and so on.
          If you try to define an observer only as being capable of making some sort of interpretation, i.e., (from your own examples), by doing a prediction or applying a convention, you get an interesting problem. Schrodenger described this in the famous Cat Paradox, but let's scale it up a bit. If an observer has to be able to think, even very simplistically, then we can't logically ask what Jupiter is. I can, for example, say that, about an hour ago, Jupiter was a planet. because I looked up and saw it, and was capable of thinking about the difference between a planet and other things that look like one. But Jupiter, right now, isn't any actual thing, it's an uncollapsed state vector involving umpteen bajillion fundamental particles and a relativistic light cone about an hour long, and all of that becomes just a probability and not an actuality. If there's limitations like you have suggested, then any time it's cloudy everywhere a moderately educated person can see Jupiter and identify it, the state vector lengthens until the rain goes away, potentially becoming many hours long. That's one damned big 'cat', in an even bigger 'box'. Schrodinger figured a macroscopic object like a cat was big enough to show how some arguments were absurd.
            By this interpretation, every tree that falls in a forest with no observer around not only doesn't make a sound, it's an uncollapsed state vector until something which knows the difference between a tree and a shrub comes along. Does an insect tasting the fallen tree need to know that its a dead tree and not some other cellulose object before the state vector collapses? If we are the only astronomical civilization in the universe, did all those objects in the Hubble deep field photo just become objects when Hubble took the shot, or even when some human first looked at the picture? All the universe that lies outside 'the' observable radius could be one gigantic uncollapsed quantum probability function, not yet a thing, and since it is moveing away to fast for light to ever reach us, never to be an actual thing.
          All that's implied if encoding and decoding were fundamental, which Is probably why you don't like that interpretation much. If encoding and decoding are fundamental, that pretty much implies a "Big G" god to take the whole universe from probabilistic function to actuality, by observing from every point, or else a vast epistemological limbo surrounds our tiny bubble of observations. We can justify claiming that mathematical calculation based models describe a lot of events in a way that makes them easier to address, and such, as you've suggested, but if we claim to know for a fact that these reflect a fundamental truth, we'e claiming to know that something omnescient exists, and that's probably not a place a lot of the 'universe as computation' theorists want to go.

Re:I don't think encoding/decoding are fundamental (0)

Anonymous Coward | about 9 months ago | (#45073975)

aren't all the problems due to trying to apply micro concepts to the macro world? or the other way 'round?

computation only comes from human programming (1)

globaljustin (574257) | about 9 months ago | (#45073983)

this is a true statement:

Why can we not think of the information as being embodied in "some aspect or other of" the matter and energy undergoing evolution. It is only some observer that needs to see the information as having been encoded or decoded.

I think TFA (and Turing too, but we'll get to that) make a fundamental mistake that leads them to these TED-talk kind of wild eyed pop-science speculation.

It relates to social construction of reality: http://en.wikipedia.org/wiki/Social_constructionism [wikipedia.org]

So, my point is: the very *idea* and *definition* of the term 'computation' is a human-created contextualization of the way we observe the universe to work.

humans made machines (computers in this case) to automate a task: specifically in the case of the 1st computer [wikipedia.org] it was for automatically doing long math problems.

all of 'computation' in the history of the known universe has been done by machines programmed by humans

that's what it is

the deeper problem, IMHO, is a computing model based on the 'Church-Turing' Thesis of universal computability to describe computation...its sort of like an unnecessary abstraction layer

it's time for a better model...information theory and communication theory are helpful here...I believe a *cybernetic* [wikipedia.org] model is the proper understanding of computation.

Why? Computation is nothing more than humans observing information flow through a system, a system which *processes and changes* the information in a predicted and predetermined (*programmed*) way.

For this, I see the Shannon-Weaver Communication model [wikipedia.org] as the proper conceptual starting point for formal understanding of 'computation'

Just imagine Von-Nueman Architechure overlayed the Shanon-Weaver Model diagram...**that's** a cybernetic approach ;)

Nonsensical sentence (0)

Anonymous Coward | about 9 months ago | (#45072607)

>The idea that every physical event is a computation has spread like wildfire through science. That has triggered an unprecedented interest in unconventional computing such as quantum computing, DNA computing and even the ability of a single-celled organism, called slime mold, to solve mazes

Quantum computing is no less physical than classical computing. DNA computing is entirely different than quantum computing. They have almost nothing in common. Is OP trying to say that physical models are used to perform computing? That is always the case. OP's hypothesis makes no sense.

Re:Nonsensical sentence (1)

Suiggy (1544213) | about 9 months ago | (#45074037)

OP is referring to the paradigm shift of digital physics/pancomputationalism/holography where matter and energy are no longer fundamental, but rather emergent from information. However, the author's of the paper don't know what they're talking about, they're playing with semantics and dictionary definitions, trying to claim that things we don't understand at a macroscopic scale due to complexity aren't computation.

Well, I have a theory (1)

Anonymous Coward | about 9 months ago | (#45072633)

Point particles come from the interaction of various waves which carry force. Points don't even take up space. The Universe is one giant 2D wave, and all 3D space is holographic illusion.

Re:Well, I have a theory (5, Funny)

Anonymous Coward | about 9 months ago | (#45072975)

Point particles come from the interaction of various waves which carry force. Points don't even take up space. The Universe is one giant 2D wave, and all 3D space is holographic illusion.

Look, seriously, Doom was DECADES ago at this point. The rest of the world's moved on, you really need to stop living in the past and base your universal theories on something OTHER than an engine Carmack made back in the DOS era.

Re:Well, I have a theory (1)

Codifex Maximus (639) | about 9 months ago | (#45073019)

To me, there are only four primary dimensions.

Length, Width, Height and Time.

The L*W*H dimensions ARE space. No need for a space dimension.

Time is a measurement used to delineate Frames.

I would say, do not limit yourself to only thinking in 2 dimensions as you cannot live in them. It takes 3. I will say that it also takes a bit more thought to see the world or understand it in 3 dimensions. One should try.

Re:Well, I have a theory (1)

hazah (807503) | about 9 months ago | (#45074857)

The holographic principle simply states that information of 3d space can be encoded onto a 2d surface. Likewise for 4d spacetime & 3d space. So any number of dimentions can, in fact, be represented within the confines of that number -1 dimentions. At least, according to the theory.

Re:Well, I have a theory (0)

Anonymous Coward | about 9 months ago | (#45073589)

http://gizmodo.com/our-universe-might-just-be-fourth-dimensional-black-hol-1410271260

Similiar idea but as a 3D wavefront in 4D space.

Re:Well, I have a theory (1)

K. S. Kyosuke (729550) | about 9 months ago | (#45074041)

The Universe is one giant 2D wave, and all 3D space is holographic illusion.

...and so are D cups? I feel cheated!

Probably meant "useful computation" (1)

Anonymous Coward | about 9 months ago | (#45072641)

The article claims that computation requires the theory behind it to be well-understood.
However, information processing is computation, whether you understand it or not.

That would be like saying that the brain did not compute because our theories behind how a brain works are insufficient to fully understand it in its entirety.

Definitions (1)

doconnor (134648) | about 9 months ago | (#45072659)

Sounds like they are arbitrarily defining computing as a simulation of the universe, therefore the actual universe cannot compute. I think this unnecessarily limiting people's imagination.

Besides, from the inside of a simulation its all real to you.

Re:Definitions (3, Insightful)

gstoddart (321705) | about 9 months ago | (#45072787)

Sounds like they are arbitrarily defining computing as a simulation of the universe, therefore the actual universe cannot compute.

Or that they're saying the universe doesn't need to do calculations to determine where a falling object is going -- it just falls according to the laws of physics and doesn't need to be calculated.

I think this unnecessarily limiting people's imagination.

Does 'imagination' in this context actually tell us anything? We know that we need to do calculations for this stuff, but how does the assertion that the universe isn't doing the calculations limit our imagination? Stuff happens according to physical laws, the behavior is inherent to reality. Nobody has to do the math, it just happens.

Besides, from the inside of a simulation its all real to you.

Very meta, and equally meaningless. Yes, if we were in a simulation, we'd likely never know.

But given that we have no evidence to suggest we are, any assumptions around the notion that we are (or may be) are pretty much useless to us unless we can figure out the gaps in the simulation.

To me the suggestion we're living in a simulation serves no other purpose that throwing out something wacky to stump people at parties, but otherwise doesn't seem to have any application to understanding our universe.

Re:Definitions (1)

Obfuscant (592200) | about 9 months ago | (#45073003)

Or that they're saying the universe doesn't need to do calculations to determine where a falling object is going -- it just falls according to the laws of physics and doesn't need to be calculated.

Sounds like a Schroedinger's Cat of physical computation.

Hold a bowling ball over a cat. Drop the bowling ball. The cat is either a live or dead, the actual state cannot be determined until something decodes the computation done by the falling (or not falling) bowling ball.

"Damn, my printer jammed, we're overrun by half-dead cats." "We're half-overrun by dead cats?"

Re:Definitions (1)

camperdave (969942) | about 9 months ago | (#45073213)

"Back in Nebraska, our cat got stuck in my brother's camp trunk, and we did not need to open it to know there was all kinds of dead cat in there." - Penny.

Re:Definitions (3, Informative)

Sarten-X (1102295) | about 9 months ago | (#45073023)

doesn't seem to have any application to understanding our universe.

If we are a simulation, we may be able to discern exactly what we're simulating, and why. Theology aside, even discovering that our universe functions like a simulation may allow us to seek out and utilize aspects of the simulation that are useful to us.

Consider, for example, if we could simply access an information store outside our universe from anywhere within it. Even a single bit being accessible would offer the ability to have near-instant communications with other planets, or perhaps even other stars. If we could push matter out of or into the universe, we'd have an effective teleportation mechanism.

Science is all about figuring out the rules of our universe. Being inside a simulation means there are other, possibly different, rules outside, so breaking out means we have new capabilities that are impossible within our universe.

Re:Definitions (1)

marcello_dl (667940) | about 9 months ago | (#45073191)

> If we are a simulation, we may be able to discern exactly what we're simulating, and why.

No wai and I can prove it.

You have an mp3 player with two songs in it. The random playing algorithm makes it play the first song, the second song, the first again the second again and so on, because when it has to choose the next song there is only the other one available.

The normal playing algorithm plays the first song then the second song then the first song and so on EXACTLY LIKE the random playing algorithm.

Without looking at the mode, relying on your ears only, you would likely theorize that it's playing sequential, and some nerd would come up with the theory that it's playing random, some other nerd would argue about occam's razor and bullshit like that. In truth there is no way to discern the truth of the programming until you get to see the mode.

Think about it as plato's cave revisited.

Re:Definitions (2)

Sarten-X (1102295) | about 9 months ago | (#45074349)

Your "proof" only illustrates one particular case, which does not necessarily apply to the question at hand.

It is indeed like Plato's cave, and the same lesson applies: Occam's razor is not always correct. Sometimes there are really weird truths, and with enough experiments, they can be discerned. Perhaps that MP3 player takes a little longer between songs while it tries to randomize the list. With a long enough recording of the playback at a high enough precision, the slight delay can be noticed, and that analyzing nerd can announce the mode with certainty.

The fundamental basis of all science is that we are wrong. Aristotle was wrong, Newton was wrong, Einstein was wrong, Hawking was wrong, and every scientist today is probably wrong about something. The scientific method allows us to become right. Each successive scientist makes more and better observations than his predecessors, notices what observations don't match the old law's predictions, theorizes new hypotheses to fit existing data, then experiments to test the hypothesis. Eventually, a new theory replaces the old one for situations where the new (and probably more complex) theory is necessary.

In your thought experiment, you said "relying on your ears only". This is as much a mistake as saying that time is measured on a wristwatch only, which is, of course, far too imprecise to test the effects of relativity at attainable speeds. As technology improves, so does our ability to measure and observe, giving us more data on which to base our hypotheses, such as the few-cycle timing differences in the playback. There may be just such a slight defect in our universe, that would open up a whole new field of study in trans-universal physics. There also may not be. We haven't observed such a thing yet, but we should not be so arrogant as to assume that our current knowledge is absolutely all-encompassing.

Re:Definitions (0)

Anonymous Coward | about 9 months ago | (#45074709)

You have an mp3 player with two songs in it. The random playing algorithm makes it play the first song, the second song, the first again the second again and so on, because when it has to choose the next song there is only the other one available.

Your random number generator is at fault there. If it were truly random, it wouldn't have any qualms about playing the same song ten times before it hit the second song. If your random number generator is broken (and yours certainly is), it isn't random.

Re:Definitions (1)

gstoddart (321705) | about 9 months ago | (#45073225)

If we are a simulation, we may

I see ifs, maybes, what ifs, a few 'could bes', and wouldn't it be awesome if ... and nothing at all to suggest any of it is real or relates to our universe as we see and experience it.

Science is all about figuring out the rules of our universe.

Yes, yes it is.

It isn't about saying "gee, if our universe wasn't really a universe, then all of these things could be true and I could have a pony".

What you're describing is at best speculative fiction, and at worst just making shit up. Anything but science.

I'm not aware there's any credible evidence to suggest we are in a simulation which means everything after your first 'if' is pretty meaningless.

Science only deals in what we can see and observe, and that's not what you're describing. In fact, I'd say it's pretty much the opposite.

Re:Definitions (1)

Sarten-X (1102295) | about 9 months ago | (#45074859)

Yes, everything I said was speculative. No, I don't think we're actually in a simulation. That does not mean that such a thing has been proven impossible. Until it is, it cannot be dismissed as a theory to explain observations that don't fit existing theories.

Science only deals in what we can see and observe

That is not limited to what we can see or observe right now. Perhaps a future observation will reveal discrepancies in We could not observe the Higgs boson until long after its existence was theorized. In fact, I think your original post said it well:

But given that we have no evidence to suggest we are, any assumptions around the notion that we are (or may be) are pretty much useless to us unless we can figure out the gaps in the simulation.

But where do we look for those gaps? What experiments should we run to determine whether that speculative instant communication is possible? We must consider the ramifications of such speculation, find a testable observation, then try it. That is curiosity. That is what drives discovery.

Re:Definitions (1)

UnknownSoldier (67820) | about 9 months ago | (#45073381)

> If we are a simulation, we may be able to discern exactly what we're simulating, and why.

As a mystic the reason is quite simple: The growth and evolution of consciousness.

There is one primary reason the [physical] universe exists: Relationships.

What, you thought human consciousness was the only kind !? There is NO-THING BUT consciousness.

See Peter Russel's excellent talk:

The Primacy of Consciousness - Peter Russell
http://www.youtube.com/watch?v=-d4ugppcRUE [youtube.com]

Re:Definitions (0)

Anonymous Coward | about 9 months ago | (#45073277)

It has as its application maintaining for consideration the notion of the universe as Designed, as the precise important reason, important in your very own mind, that you go to such strenuous argument to state that it isn't important.

The core Interpretations of QM (e.g. Copenhagen, Everett) do not have differentiating evidence for them either. Nor can we currently ascertain knowledge of what exists "beyond" the framework of possible existences they suggest. That doesn't mean we won't.

Re:Definitions (1)

Artifakt (700173) | about 9 months ago | (#45073639)

I have absolutely no interest in learning if I exist inside a simulation or not, unless it's programed with accessable cheat codes.

Re:Definitions (1)

NoImNotNineVolt (832851) | about 9 months ago | (#45073743)

To me the suggestion we're living in a simulation serves no other purpose that throwing out something wacky to stump people at parties

... whoa... </neo>

Re:Definitions (0)

Anonymous Coward | about 9 months ago | (#45074519)

Sorry we didn't get you before you hit puberty, but you would NOT want out of the fantasy at this point, believe me.

-Neo

You will rue the day when you discriminated (0)

Anonymous Coward | about 9 months ago | (#45072701)

against slime mold! The Great Ooze does not know mercy!

Nethack (1, Funny)

CanHasDIY (1672858) | about 9 months ago | (#45073709)

This slime mold is delicious!

Different types of computation (5, Interesting)

naasking (94116) | about 9 months ago | (#45072725)

The type of computation discussed in this article is not the type of computation used in the phrase "every physical event is a computation". These physicists are trying to discern computation from physical processes by discerning whether the process can encode information in its initial conditions, and other information can be extracted from its results. This is good when trying to determine which processes lend themselves to building computers, but it does not address the question of whether the universe is a computer, and whether the laws of physics are merely closed form equations describing some of its operational semantics.

Re:Different types of computation (1)

minstrelmike (1602771) | about 9 months ago | (#45072845)

imo, the entire discussion and investigation comes down to one question: How do you define information?
IF DNA is encoded information and keeping a similar DNA 'alive' for billions of years is considered success (a Species is kind of a generalized unknowable DNA), then slime mold is successful. The randomization of sexual reproduction where all the stuff gets shuffled all the time (between generations), is one method of 'predicting' the randomness of the future. Or atl elast dealing with enough to get a good chance to try a second, then third, then fourth prediciton.

What exactly does being informed thru information mean?

useful/useless computation (0)

Anonymous Coward | about 9 months ago | (#45072801)

It seems to me that the differences expressed in the article is postulating may be better expressed by a distinction between useful and useless computation, which can than be defined as relative to the observer.
maybe that's just because I can't think of anything that we can observe, or infer, which has no effect on the physical world

I wouldn't necessarily call slime mold onecelled. (2)

Sique (173459) | about 9 months ago | (#45072825)

It's much more complicated than that. Myxogastria can be onecelled and mononuclear, and they can be multicelled and multinuclear, and they can even be onecelled and multinuclear - all within the same organism. A single plasmodium cell can contain up to 10 mio nuclei and span several square meters. Thus it would be better to call the plasmodium acellular, as it has no inner cell structure.

Adventures in epistemology (4, Interesting)

Empiric (675968) | about 9 months ago | (#45072833)

For example, the processes that slime mould uses to solve a maze are largely unknown. For this reason it is not computation.

Don't we usually declare characteristics of things based on what we know about them, rather than on the basis of not knowing about them?

Seems like a strange kind of subjective solipsism--"what is, is dependent upon on what I currently know is".

Re:Adventures in epistemology (1)

nashv (1479253) | about 9 months ago | (#45074251)

Yeah, who the hell are these authors anyway? Engineers?

Let's Test Some of These Assumptions (0)

Anonymous Coward | about 9 months ago | (#45072863)

"Without a good understanding of the underlying physics and solid engineering to make the device usable, a physical system simply evolves rather than computes." Okay - Is the Earth a computer? The earth, as a device, is definitely usable - it is specifically "engineered" to sustain human life, unlike any other system in the universe. We have a good understanding of it and we've engineered subsystems within it to even make it more usable. In fact, it generates spreadsheets (I have yet to see a quantum computer generate one) in some of its subsystems.

So, using the blog post's assumptions, the earth doesn't just evolve, it also computes. Correct?

Semantic triviality (2)

oldhack (1037484) | about 9 months ago | (#45072865)

See subject.

Re:Semantic triviality (1)

Suiggy (1544213) | about 9 months ago | (#45073871)

Agreed. The authors of the papers are just old biologists who don't like the idea of pancomputationalism and digital physics infringing upon their domain. They want the magic of life to remain elusive. The truth, however, is that computation *is* the magic they so desire.

BS (3, Interesting)

nashv (1479253) | about 9 months ago | (#45072869)

I RTFAed. Their theory is essentially that computation can only be said to have occurred if you know the physical nature / laws that allowed the computation to occur.

Which is BS. There are plenty of people who can add 2 numbers on a calculator without knowing anything about electrons, bits, electronics etc. You can extend that until the number of people who understand specific physical laws underlying a computation is zero.

Since when is human knowledge the test for whether any computation is happening? All they are saying is "If we don't understand it, we will not call it computation." Way to go with the semantic circus.

Re:BS (1)

NoNonAlphaCharsHere (2201864) | about 9 months ago | (#45073027)

They're trying to draw a distinction between computation and experimentation. Essentially, they're saying that if your model/mental-map of the problem is good enough, i.e. you have good predictive power over your methods, then you are performing a calculation/computation. If you're not so certain of the outcome, then it's experimentation. But I do agree, it's kind of a semantic knife's edge.

Re:BS (1)

wonkey_monkey (2592601) | about 9 months ago | (#45073159)

Since when is human knowledge the test for whether any computation is happening?

Are you sure anyone's referring to human knowledge? I've only skimmed it but got the impression that their criterion is that there is some information (in the new-fangled sense) to be had at the end of it - it doesn't have to interpreted by a human, it simply has to be available (to a human, or a cat, or a particle in the vicinity).

Re:BS (2)

nashv (1479253) | about 9 months ago | (#45073385)

There is always information around (new-fangled sense). In fact, Any dissimilarity in the universe of any kind is information. Presumably, the ability to recognise such dissimilarities is required for any information retrieval, and in the end humans must detect it if we are to talk about if it is computation or not.

The point they are making is that one must understand a systems physical laws governing events for it to be a computation. Wrong. What they say actually applies to the fact that we must understand physical laws to use a sequence of physical events as a computer. In fact, the computers we use are simply devices where we can set up physical conditions in such a way that they reflect our problem (encode) and then let the physics solve it. That ability to set up physical events in particular ways makes encoding easier. But it is NOT a requirement. You could develop an encoding scheme that allows you to put in your problem in terms of whatever states a system has. That is exactly the principle behind DNA computing. The physical events of DNA polymerization and annealing of complementary strands are computing all the time. If the information makes any sense to you then, you have not magically invented computation, you just discovered a way to use a physical system as a computer for your pet problem.

All computation needs is that some physical events happen in a predictable manner (whether you understand why or not). I am doing the computation all the time, but nobody knows why positive charges and negative charges attract. It's not important to use electrons as a computer as long as I am sure they do. The same thing applies to their slime mould example. It solves a maze. It's. I don't know how it does it...but it predictably does. And that's a computation.

Universe does compute - per se. (1)

Codifex Maximus (639) | about 9 months ago | (#45072887)

I think whether or not the Universe computes is relative.

What is it you're trying to compute? If you are trying to compute the dynamics of the Universe then the Universe does compute. It computes itself better than any other model.

If you are talking about abstractions then probably computers do very well give proper instruction and dataset.

To get a computer to compute the universe is like trying to force a very large round peg into a very small square hole.

When in doubt, ask Einstein. (1)

briancox2 (2417470) | about 9 months ago | (#45072933)

"God does not care about our mathematical difficulties. He integrates empirically." --Albert Einstein

42 (1)

sycodon (149926) | about 9 months ago | (#45072995)

Slashdot is slipping. Twenty Five posts and not one mention of Douglas Adams.

Re:42 (1)

wonkey_monkey (2592601) | about 9 months ago | (#45073085)

We're all waiting to claim post 42, of course.

Re:42 (1)

dgatwood (11270) | about 9 months ago | (#45073127)

The mice were mentioned in the "department" line, so we assumed we'd be modded redundant. But as long as we're going down that path....

Ooh. I know this one. The computation stops when we get bulldozed to make room for an intergalactic superhighway.

Re:42 (1)

DutchUncle (826473) | about 9 months ago | (#45074087)

I'm shocked, shocked and dismayed, that I had to scroll down this far to find that someone had beaten me to it.

The universe computes on third shift (1)

nani popoki (594111) | about 9 months ago | (#45072999)

On first shift, you submit the keypunch forms.

Slime mold does perform computation (1)

wiredlogic (135348) | about 9 months ago | (#45073017)

Slime mold senses its environment and reacts accordingly. That is computation in the broader sense used by physicists. It isn't engineered (unless you are of a certain ilk) but it is an organized, coherent system.

Toward Egan/Wolfram Territory (2)

Nova Express (100383) | about 9 months ago | (#45073029)

I.e., the idea of the entire universe as constituting some sort of universal computational substrate.

The idea is probably wrong, mainly because every "my conception of the fundamental nature of the universe based on just discovered science" is wrong, due to the time-bound nature of our perceptions.

Proof by axiom (1)

Froggie (1154) | about 9 months ago | (#45073045)

By defining computation to be X and not Y, I have proved that X is computation and Y is not.

Yes, terribly helpful, that.

Planck physics (0)

Anonymous Coward | about 9 months ago | (#45073063)

It's probably wrong, but I really like the idea of the universe being a big physics engine with a step time of one planck second.

The computation is ruined (1)

cold fjord (826450) | about 9 months ago | (#45073217)

Based on the story one might speculate the all processes in the universe could produce a computation and provide an answer. If so, then the universe has been calculating in this story as well. The number of posts in this story prior to this post is 42. My post now invalidates the universal answer by changing the number of posts to 43.

Angles and Pinheads (1)

pseudorand (603231) | about 9 months ago | (#45073259)

Does this remind anyone else of how religious philosophers of days past used to argue over how many angles could dance on the head of a pin? I'm not sure about the angles part, but there are surely some pinheads in this story.

Re:Angles and Pinheads (2)

MachDelta (704883) | about 9 months ago | (#45073371)

Let me guess - those dancing angles are doing the tan-go?

Re:Angles and Pinheads (1)

Anonymous Coward | about 9 months ago | (#45073831)

Do you know the difference between angel and angle?

Re:Angles and Pinheads (1)

pseudorand (603231) | about 9 months ago | (#45074043)

Apparently not, since I did it multiple times. I blame the US public education system.

Wrong. (1)

VortexCortex (1117377) | about 9 months ago | (#45073263)

However, that may need to change now that physicists have worked out a formal way of distinguishing between systems that compute and those that don't. One key is the ability to encode and decode information. 'Without the encode and decode steps, there is no computation; there is simply a physical system undergoing evolution,' they say. ... So slime mold fails the test while most forms of quantum computation pass."

The slime mold is computing the optimal solution to the task at hand. Evolution is the computation, the DNA contains the encoding and decoding. DNA is self describing information -- A proposed solution to the problem space of the environment. I just despise when morons fail basic Cybernetics 101. Explain reproduction if there is no encode / decode phase... ugh.

Well Duh... (0)

Anonymous Coward | about 9 months ago | (#45073429)

... at night of course...

Alternate Universe (0)

Anonymous Coward | about 9 months ago | (#45073573)

+++ Divide By Cucumber Error. Please Reinstall Universe And Reboot +++

Etc. (2)

Impy the Impiuos Imp (442658) | about 9 months ago | (#45073669)

Physicists, please leave this to computer people. Interpretation is just a transformation, and is no magic door to computational efficiency.

If a slime mold could, via interpretation, solve some NP-Hard problem, that would be an astounding result with major implications for the computational ability of the universe.

This is independent of the interpretation. It is the equivalency of reducing a problem to another, of which physicists are indeed well aware.

When does the universe compute? (0)

Anonymous Coward | about 9 months ago | (#45073673)

I think the phrase "spread like wildfire through science" is a little over the top.

As I recall, Edward Fredkin's interesting ideas about Digital Philosophy (roughly speaking, the universe as a computer), are far from being accepted by the scientific community.

Lets rock this topic like its the 90s! (1)

YoungManKlaus (2773165) | about 9 months ago | (#45073955)

after all that's roughly how current it is ... I remember learning about these topics in bio (slime mold) and physics (quantum computing) back in high school (or rather the equivalent in my country), and the material was already some years old - and already claiming "10 to 15 years" ... well, that timeframe was over last year iirc

Sounds like nonsense to me (2)

gweihir (88907) | about 9 months ago | (#45074017)

"A physical system undergoing evaluation" is pretty much what a computation on a physical device looks like. Seems some physicist(s) with their usual search for meaning when the midlife-crisis strikes but little idea of Computer Science drummed something up that does not make a lot of sense. The issue is of course that the encoding and decoding steps (properly called abstraction and application) are only necessary when you have a computing device using a different primary mechanism that the device the calculation apply to. For example, when doing analog computations in a radar system, you do not change the mechanism, the signal already is electrical and analog. Hence when doing, day, computations for gravity, there would well be an invisible tiny "gravitational computer" in any particle affected by gravitation that uses the available input directly.

Of course, there is always the (likely) possibility that this whole universe is only a simulation, and all perception of it we have is a cleverly crafted illusion. In that case the abstraction step is not necessary either, except possible in the bi-directional channel that delivers the illusion to each of us. (Solipsists win the most here: Only one bi-directional channel needed for the whole universe ;-)

Re:Sounds like nonsense to me (0)

Anonymous Coward | about 9 months ago | (#45074729)

Of course, there is always the (likely) possibility that this whole universe is only a simulation, and all perception of it we have is a cleverly crafted illusion. In that case the abstraction step is not necessary either, except possible in the bi-directional channel that delivers the illusion to each of us. (Solipsists win the most here: Only one bi-directional channel needed for the whole universe ;-)

You seem to be assuming that if it were a simulation then we would have to exist in some capacity outside of it, like in the Matrix. Why is that? If it is just a computer running a simulation based on the laws of physics then we could be just bits of memory in the computer running the simulation. But of course from our perspective we would still be "real".

Cue the dominant paradigm... (1)

hawkfish (8978) | about 9 months ago | (#45074165)

In the 18th century, the sexy model of the universe was a clockwork mechanism because that was the coolest tech available at the time. Move forward three centuries and suddenly the universe is a digital computer because that is the new trendy tech. Never mind that 50 years ago Feynman showed that the universe is not efficiently computable by a Turing machine...

Re:Cue the dominant paradigm... (1)

nashv (1479253) | about 9 months ago | (#45074333)

This is what Feynman said

""It always bothers me that, according to the laws as we understand them today , it takes a computing machine an infinite number of logical operations to figure out what goes on in no matter how tiny a region of space, and no matter how tiny a region of time. How can all that be going on in that tiny space? Why should it take an infinite amount of logic to figure out what one tiny piece of space/time is going to do? So I have often made the hypotheses that ultimately physics will not require a mathematical statement, that in the end the machinery will be revealed, and the laws will turn out to be simple, like the chequer board with all its apparent complexities".

. There is a subtle difference.

Re:Cue the dominant paradigm... (0)

Anonymous Coward | about 9 months ago | (#45074589)

Feynman also hypothesized that a quantum computer CAN efficiently compute the universe. Seth Lloyd later proved that and he suggested (in his book "Programming the Universe") that the universe is indistinguishable from a quantum computer computing the laws of physics. The fact that a classical computer cannot do it efficiently is irrelevant.

no, not really (1)

stenvar (2789879) | about 9 months ago | (#45074179)

However, that may need to change now that physicists have worked out a formal way of distinguishing between systems that compute and those that don't.

Just because a bunch of physicists propose such a "formal way" doesn't mean that that formal way is actually correct or even meaningful. The history of science is littered with physicists proposing all sorts of things outside physics, almost all of which have turned out to be b.s.

Sounds like a love child of physics and philosophy (0)

Anonymous Coward | about 9 months ago | (#45074289)

Philosophy always just makes my head hurt beyond a certain simple level. At least physics makes my head hurt for a purpose. I'd like to get something out of my headaches other than a paper that only others of my kind will read. At least... that's my philosophy...

Searching (1)

b4upoo (166390) | about 9 months ago | (#45074407)

Philosophers tend to want to create specialized definitions and terms in order to project that philosophy so that it can be more broadly applied. I think this is what we are seeing here. In specific they mentioned slime mold and encoding and decoding. Actually slime mold is encoded with DNA and the function of the slime mold in navigating the maze reveals the decoding expressed as the function of slime mold. If our human abilities were more advanced we should be able to determine the future functional abilities or probabilities of a function by examining the DNA encoding directly rather than determining its function by observation of the slime molds activity.
                    Essentially they seek clarity on what defines computation. In this muddy world clarity is rarely available.

Obligatory SMBC (0)

Anonymous Coward | about 9 months ago | (#45074649)

As usual either Zach Weinersmith or Randall Munroe, the two greatest minds of our era have already forsaw this news...

In this case it's Zach!
http://www.smbc-comics.com/?id=3054 [smbc-comics.com]

Pen and Paper? (1)

pscottdv (676889) | about 9 months ago | (#45074783)

Computation is essentially the same process. A computation uses the evolution of a physical system to model an abstract theory.
But this only works when the link between the real and abstract worlds is clear and well understood.

Yet strangely I can work computations using pen and paper using only the evolution of the poorly understood system consisting of my brain, arm, hand and eyes.

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