Is the universe discrete or continuous?

What proof is there that the universe is discrete and what proof is there that the universe is continuous?

You can never know if the universe is discrete for certain since even if it appears so there may still be some undetectable phenomena you are unaware of.

You can never find evidence to suggest the universe is continuous as there can never be a scientific instrument capable of infinite accuracy.

And you can never know that you're not just dreaming all this, etc.

Science isn't about absolute truth.


As for discrete vs. continuous: We've slowly been uncovering more and more discreteness in physics, so I wouldn't be surprised if everything, including spacetime, turned out to be discrete (or more accurately; 'turned out to be best described by a discrete model').

well then, given those two points, i suppose the thread is over.

speaking of science,

doesn't it seem ignorant to think that there isn't something more to the universe than what meets the eye? I'm not really talking about a theistic god, but just... something more... i mean we can only experience the universe through our five senses and we aren't the pinnacle of evolution, because there is no such thing. How much of what we think we know and experience is really just our minds/brains filling in information for us, just to cope and survive?

I know it's 'useless' to think of such things, because it just raises 'what if we're all just brains in a vat' type scenarios that have no practical application to our lives, but even if it is just philosophical wankery, i've seen very few people admit to the fact that we just dont know, and probably can't know.

>>4
lots of people admit to that, its skepticism.  no one likes to argue with a skeptic though so they don't get involved in many conversations.

>>5
Because there's no point.  What if we ARE brains in vats?  It's empty untestable speculation.  A non-testable proposition does not rise to the level of being a hypothesis.  It's a meaningless noise.

>>6
I know this is vague, but what if we ARE brains in vats? Or if any number of other untestable assertions are true? Yes, it has no application to us and there is no way of knowing. But, assume that an assertion is true, doesn't the simple fact that IS true have 'meaning'?

I guess i may be confusing myself here, but, just by virtue of it being true, shouldn't it be more than 'meaningless noise' to us?

I guess it comes down to the 'meaning' of truth and the nature of reality.

The universe is a confusing place, forgive me for being dense.

Discussing (or in fact even thinking about) statements with unknowable truth-values is a waste of time. Pretty much by definition, the answer to the 'what if' question is always going to be 'it wouldn't affect anything'.

>>7
Because if we can't test it, we can never know whether it's true or not.  It's unprovable one way or the other.  So it tells us nothing whatsoever.  It's meaningless and pointless.

What if there's an invisible two-inch-tall unicorn hovering just above your head at all times?

What if an invisible Flying Spaghetti Monster created the universe, and us, ten seconds ago with false memories of previous existence?

What if we're all in the Matrix?

Meaningless noises, all of them.  Putting anything more than perfunctory effort into thinking about any of them is mental masturbation.  If it can't be tested, if it can't be proven one way or the other, its net information content is nil.

you find it pointless to argue over unknowable questions when this question itself is about whether anything is knowable.

is a question meaningless if we can't answer it?  notions of scientific testing seem practical, but is there a solid logical reason to believe that science has proven anything or can ever?  every "what if" is valuable because it is a mark of doubt, and people too often judge things with certainty.

can you prove anything one way or the other?  or does everything then, as you say yourself, lead to nil.  propose one thing that you can prove to me.  i will question your reasoning and assumptions.  at some point you will protest that i do so mindlessly and beyond meaning.  it is precisely at that point you have chosen to make assumptions you can not prove.

what differentiates this "meaningless noise" from the "meaningful"?

>>is there a solid logical reason to believe that science has proven anything or can ever?

You're right.  I'm going to throw away my computer, get off the Intermaweb, and live out the rest of my days in a cave.  Fucking scientists, what do they know?  They think they're so smart, just because they search for empirical truth and create things that work.

>>what differentiates this "meaningless noise" from the "meaningful"?

Empirical testability.

>>12

what meaning is there in that?  its just demonstrating that we can come up with conjectures that withstand repeated tests, as many as have been performed up until now anyway.  maybe its useful because with it we tend to produce technology which is both consistent with and based on our observations and apparently good for us?  what is "useful", what is "good"?  there is so much assumption in this.  we might assume correctly, but it is assumption nonetheless.

>>13
That's what we accept to be labeled "meaningful" in a scientific context. There are no absolute definitions of words.

You know, the reality here is that you can still get your PhD on the basis of such a question as long as you mathematically model the characteristics of a discrete universe.

After all, we mint PhDs for string theory CONSTANTLY, and there's not a shred of evidence that's been produced from any experiment to support string theory.  These so-called physicists are just mathematicians.  So, why not a "discrete brane" physicist?  We're all making this up as we go along, and don't bother with the Old Way of setting up experiments to test theories.  So, why not?

>>15
Since when was theoretical physics ever *not* "just math?" You are confusing theoretical and experimental physics.

>>14
thats pretty much what it comes down to

>>2
I know that. I should have phrased my first sentence as "What evidence is there to suggest that the universe is discrete and what evidence is there to suggest that the universe is continuous?", but knowing the attention span of the average 4channer I decided to use "proof" instead.

You did give some loosely defined evidence anyway, I think you are referring to the planck units and the 5 constants, however the constants alone do not suggest the universe is discrete or continuous which leaves the planck units which is where this argument hinges.

>>3
>>7
>>8
We can never know anything for certain, but we can make realistic assumptions and predictions like if I lift this pencil up and drop it the pencil will fall. I may not be sure exactly how it will fall, perhaps even a freak gust of wind will make it travel upwards, but that still obeys my assumption that it exists within the degree of accuracy that classical physics holds true and it will fall.

>>4
I never said there wasn't. I think it is better to induce answers from the facts than try to look for facts which fit into an answer you are looking for. People who look for a "theory of everything" tend to achieve less than people who are attempting to find trends and patterns from the results of unexplained phenomena.

>>5
If you do that then you get nowhere.

>>6
Which is why it is better to get facts first then induce answers from them rather than the other way round.

>>13
>>14
>>15
>>16
>>17
Actually what the results mean is an important part of scientific method, this problem was solved by Kant 200 years ago and founded the general basis for it. Long story short there are 2 types of thoughts, a posteriori and a priori. A posteriori represents facts like tangible properties and a priori represents assumptions induced from the facts. The validity of an assumption is a probability, every time I drop a pencil it falls and if I were first experiencing this phenomena, after a few hours of doing so it would be lunacy for me to assume that the pencil would not fall. The assumption that pencils fall when I let go in normal room conditions is valid.

Conjecture and theory are both a priori, conjecture is defined as "to conclude or suppose from grounds or evidence insufficient to ensure reliability.". By sufficient the definition means that a supposition requires that other factors need to be fulfilled in order to prove that the event is taking place or occurred. For instance someone is murderred and no fingerprints were found at the scene. Saying the boxer is responsible purely on the basis that he wears gloves would be conjecture.

I hope that clears things up and we can continue with the conersation.

>>15
>>16
I plonked you in the above paragraph along with 13,14 and 17 because it seems that the discussion now hinges on the validity of string theory. What do you think makes up validity. I think Kant had the answer to that too.

>>18

BLAHBLAHBLAH MITCH HENDERSON

really, what i was trying to get at is the fact that it makes my brain hurt to think of the limitations of my own mind.

There's always this 'box' that we just can't get out of when it comes to thought, no matter how hard we may try, and there is more than likely things outside this 'box' that we may never be able to know.

But then, how can i even have knowledge of the existence of the 'outside box'?..etc.

It kind of reminds of godel's incompleteness theorem if you picture each formal system as a 'box', you can't prove its consistency from within the box, you need a bigger box that encompasses the smaller box...ad infinitum. It feels like we / our minds are trapped inside one little box or one level of reality with no means of escape and no way to discover the 'truth'.

>>18

"Long story short there are 2 types of thoughts, a posteriori and a priori. A posteriori represents facts like tangible properties and a priori represents assumptions induced from the facts."

a priori and a posteriori are types of knowledge, not thought, there is a difference. a priori knowledge is the what we can know without reliance on experience.  its not assumption, its more accurately tautology.  it is necessarily true, provided that the logic is correct.  when you define facts as the tangible properties we can experience through observation, you've just separated a priori knowledge from anything to do with facts.  it would be very ironic to undermine a priori knowledge based on a definition.

on the other hand, a posteriori knowledge is a fact only if you assume your observations are accurate to the real existence of what you observe.  and in case your mind should wander to this point, extrapolation to the future from past observations isn't a posteriori knowledge, because you haven't observed the future event yet.

#16, even theoretical physics operates by the scientific method, which requires that when a theory is constructed, it must be testable.  If theoretical physicists sit around all the time and get involved in stuff that CAN'T be validated from experiments, then there's literally no difference between their work and fantasy fiction.

As I implied before, physics has almost literally gone off the rails and is currently crashing like detached train cars are known to do.  Disconnected from the need to validate theories with experiments, physics is becoming less and less useful.  We shouldn't be spending money on that kind of crap.  Fire all those geezers and tell them they only get paid for results that can be verified by experiments.

#18, string theory can't be valid since it cannot be validated by experiment.  Any other sentiment is NOT science, cannot be "plonked", and has no place in scientific institutions.  The trouble here is that there is an academic class that is dominating our scientific institutions, which is tainted with this non-experimentation tolerance.  As the years pass, their work becomes less and less useful to anyone but themselves.  They are only achieving a "PhD Jobs Program".  It's essentially a WELFARE SYSTEM for bookworms.

Well, like any rational person I'm against welfare for the rich and/or the capable.  Those string theorists sound like some pretty smart guys.  Fire them all and I'm sure with their great intelligence they'll find something useful to do.

>>22
In the interest of being open minded, couldn't the same things conceivably have been said of relativity during its conception?  Not suggesting that string theory is or isn't true here; just remarking.  If string theory produced a model that seemed to fit with what all we've seen, and predicted something else we hadn't previously known and could test, then it would be useful.  What all of physics lately hasn't been useful anyway?  Nuclear stuff and quantum physics are fairly recent and have produced huge effect on daily life.

#23 (skidoo!), those are good points, but they don't lead where you intimate.

The great thing about proposals like relativity was that practical experiments could at least be proposed for them.  Being practical, they could be, and WERE, carried out.

String theory is just a set of mathematical games that don't produce results that we can put to the test.  It really doesn't get any simpler than that.  Hence, string theory is at least highly suspicious as a means for determining the model of reality.  We may as well just say "GINSE[*] did it" and let all complexities become encapsulated within that explanation (kind of like rolling up many dimensions inside a string, eh?).

As regards recent physics, string theory is the crown jewel in a large ornament of useless results.  "Nuclear stuff and quantum physics" at least give us answers that guide engineering applications.  Even the second tier applications (physics-industry-applicable only) at least produces results that can be used to accomplish a physical act.  The "huge effect" you note, however, is the result of using radiation, and radiation has been well enough understood for generations to supply such a usage.  Past that point ... physics has been stagnant.  This stagnancy revolves around the current infatuation with physically-unprovable mathematical exercises!

We need to BEND METAL!  We need to MANIPULATE INDIVIDUAL ATOMS!  We need to BREAK OPEN NUCLEI!  We need to do all that nasty stuff instead of playing math games.

We understand thermodynamics, yet can't seem to deliver ecologically sustainable energy systems to the public.  Talk about a "huge effect" -- a huge NEGATIVE effect, that is.

Engineering is very accomplished across the world, but in the First World, where the huge infrastructure exists to further probe reality, we're lost in math games.

[*] GINSE = Gender-INspecific Supreme Entity

it's interesting how this thread has turned into a debate on string theory, because it actually has a lot to do with what i was getting at earlier.

I'm no expert on string theory or mathematics, but hear me out.

Let us just simply ignore the question of whether or not string theory has any predictive ability and just assume that it doesn't.

Let us also assume that the theory is TRUE.

Now it doesn't have any predictive ability, but it's true.

I think we can then divide people into two camps: those who would think that string theory is useless because it can't predict anything, and those who would see it as totally meaningful because it IS True Knowledge.

I'm a mathematical realist, so i guess this won't apply to everyone, but maybe mathematics has given us the ability to prove a theory that would otherwise be unprovable within the system of our physical universe since mathematics is a 'bigger box' that encompasses the whole of our physical world.

I think that anything that is TRUE is meaningful, regardless of it's utility to man, just by virtue of it being true.

However, this is all a hypothetical, because i firmly believe that if string theory holds consistent and all the kinks are worked out, it will have the ability to predict, we just aren't that far yet.

#25, that's just the issue.  If the theory were true, it couldn't help but produce not only testable results but other real-world applications, eventually.

You're putting the cart before the horse.  It's pointless to say "assume it's true" and then laud the theory.  Good stuff comes from proven truth.  Unproven truth (like offered by religion) becomes a horror in short order.  Being unproven, soon enough the so-called truth becomes subordinate to some personality or faction and goes completely awry.

The way the "physics industry" is going, hordes of math-gamers are going to get paid great salaries for doing NOTHING to advance the capabilities of mankind.  No value will be produced.  Why would we be paying them?  Oh, yeah, that's right:  because due to the prevailing cultural propaganda, they would be dealing with "truth" and "pure research".  What a load of hogwash!

There is no need to excuse string theory by asserting there are still "kinks" that hamper its predictive ability.  There's enough known now to make predictions and perform tests.  But string theory is intrinsically unable to do either of that.  That's some KINK.  We may as well discuss whether the universe is continuous or discrete.  How about we're not actually walking around in flesh bodies, but are being calculated in some enormous computational matrix?  Etc.

>>21
Analytical judgements utilise a priori knowledge. A priori knowledge is indeed as much a memory as a posteriori knowledge, but it is an "equation" rather than a subject.

>>22
>>23
>>24
>>25
>>26
Assuming string theory is true, I do not believe the heisenburg uncertainty principle completely prevents the possibility of testing string theory since observations are not restricted to natural occurances. Just as quantum physics yielded transistors, if string theory is correct the understanding of elementary particles may allow theoretical physicists to "invent" something which has an observable effect and could only have been succesfully predicted if string theory is at least accurate to a certain degree. Already IBM and various universities are experimenting with the "nano tech" fad, causing materials to form orderred surface structures using radiation etc... Something in that order is still possible.

I get the impression that whether the universe is continuous or discrete has some religious connotations. Can someone explain?

ITT people who think science claims to explain the universe. Forget these wankers and theists and tell me more about this discrete universe plox.

keep yo momma's pussy discrete

Does discreteness even exist in the larger sense, considering that all real-world examples of such always involve a larger matrix for the discrete elements to exist in?

>>30
what

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.
-Richard Feynman in The Character of Physical Law, page 57.

http://en.wikipedia.org/wiki/Digital_physics

#31, I asked if discreteness even exists.  Look, in our space, we have particles zipping around "empty" space.  However, even that empty space is "something".  The original poster speculated that this empty space is itself discrete, like the particles it contains.  But even if so, doesn't that imply a larger matrix (let's call it "superspace") for our space to exist discretely in?

In short, does discreteness even exist in any real-world example?  What appears to be discrete, is actually a matrix of materials.  This means a set of discrete elements is actually a set of TWO things:  the discrete elements, and the (apparently) CONTINUOUS matrix in which they're embedded.  In short, discreteness really doesn't exist, or only exists for restricted scopes, since there appears to always be a larger continuity.

>>33
i'm still not sure i get what you mean.  i'm trying to conceptualize what you're talking about, but i don't really know what you mean by a matrix for the discrete things to exist within?  the best analogy i can think of is say, the natural numbers, they are discrete, within the reals, which are continuous.  is that what you're talking about?  when you say matrix, i think of these discrete things consisting of entries.

there are things that are discrete in the real world.  energy levels of electrons seem discrete, you cant have an electron between levels.  you can't be in between quantum states.  as far as the physical dimensions of space?  uhh, uhhunno?

#34, yes, the "integers within the reals" is a model that fits the question, if that's how you need to frame the idea.  Even if our universe is discrete (i.e. like integers), it seems rational me that there is a continuous matrix that it still resides in (i.e. like the reals).

As for the model of electrons, it's true that they can inhabit certain places in atoms, but electrons fly off into "empty" space often enough.  Are you suggesting that as electrons traverse space, they only do so along discrete paths?  I've never heard of such a thing.  The discreteness of atomic orbitals only seems to apply to that particular situation -- electrons orbiting an atomic nucleus in close proximity with other electrons.

>>35
first off, i lolled at the placement of "rational" between "integers" and the "reals", as i assume you didn't knowingly do this.  if you did, <3

but nay, i was only talking of their existence in particular energy levels.  its a separate thing from discussing discreteness of spatial dimensions.  i don't even know how to visualize energy levels, i just know they're not different distance orbits or whatever like they teach in highschool.

even if matter as a whole behaved similarly in space like distance, it would only mean that matter can only occupy certain positions of space, not that the universe itself is discrete.

#36, I like to pun.  :^)

My question aside now is if electrons in free space are subject to the Pauli Exclusion Principle, which my memory tells me governs their occupation of orbitals around nuclei.  In fact, considering all nuclear interactions, all matter at that level acts discretely, doesn't it?  If you put electrons near each other in free space, they affect each other, starting with electromagnetic force ... but then, does the PEP kick in?

However, left to its own devices, a particle can travel anywhere ... which seems to make my point for me.  The 10^80 particles in our universe seem to act like discrete elements in a continuity of spacetime, as long as they don't get too close to other particles.

With regards to the integer/real number analogy, are the real numbers discrete?

Discuss.

>>1
who cares

>>38
Reals are not discrete by the property of completeness