FirstSelector

Physics and the Cosmere

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With the recent releases from WoR has come much confusion on the nature of gravity on Roshar.  This is not a new discussion, but I'm starting a new thread because my response was getting too long.

 

As a brief introduction, there are several WoB that seem to imply that gravity has a Spiritual component.  However, he has also claimed that the laws of physics work like they do in our universe.  Reconciling these two ideas has lead to a great deal of confusion.

 

In what follows, I'm going to use an important device from theoretical physics - the "toy model."  These are simple models that attempt to explain the bulk of phenomenon by necessarily being incomplete.  Their ultimate incorrectness (as they are too simple) is overshadowed by their usefulness, as grasping the fundamental ideas is often more important than explaining all of the nuances.  As such, I am not claiming any of these models are correct, but rather I am using them to illustrate the ideas.

 

We seek to answer two separate but distinct questions: "how" the universe behaves and "why" the universe behaves in a particular way.  Despite popular opinion, physics does not claim to answer many of the "why"-type questions.  Why is physics the same in all inertial reference frames?  Why does the metric tensor obey Einstein's equation?  Why do quantum mechanical observables correspond to Hermetian operators?

 

However, postulating that these things are true in our universe answers many other "why" questions that are really "how" questions in disguise.  Why does a superconductor expel all magnetic fields?  Well, we observe them to do so, and so the question is how that arises from knowing the basic physics.  Remember that this entire field is a observation-driven discipline and we only seek to model it using mathematics.

 

I am going to make one concrete conjecture:

 

The physical laws in the cosmere are the result of interactions between Realms.  Without going too deep into general relativity, we will simply claim that "gravity" is the phenomenon of massive objects feeling an attractive force between them.  Even in our universe, it it not known why this occurs (i.e why does mass bend spacetime).  "Why" is not really relevant for predicting gravitational phenomenon - experiments show us that general relativity works.  However, the in the cosmere, there is some underlying reason due to Spiritual interactions that this is the case.  We can then rephrase the question of "why do masses attract?" as "how do Spiritual interactions generate attractive forces between masses?"  The "why" question then becomes "why do Spiritual interactions happen in a particular way" which is easily answered as "Brandon set it up that way."

 

Magic fits into this paradigm nicely.  Let's look at two examples:

 

The gravity Surge allows one to modify the direction and strength of the gravitational interaction on a massive object.  Since we know that gravity is the result of some Spiritual interaction, we then understand the gravity Surge as modifying the Spiritual properties of an object which results in a change how the effective mass-mass interaction works.

 

If we want to get slightly more technical, we could consider the following model.  Imagine that gravity works as it does on earth - an effective force due to the curvature of the metric in spacetime.  The metric becomes curved due to the presence of matter and energy.  A quick and dirty model of the gravity Surge would involve using energy (in the form of Stormlight) to locally bend the metric tensor resulting in a change of the local gravitational field.  And if the curvature of spacetime due to matter/energy is mediated through the Spiritual realm (say, energy causes the Spiritual realm to "bulge" locally and distort the Physical realm) then everything works precisely as expected.

 

The atmospheric pressure Surge can be understood in a similar toy model.  Ideal gases (and their interacting counterparts) shrink in volume when they are cooled down.  The atmospheric pressure Surge then could work in the following way: the energy contained in the Stormlight is used to remove thermal energy from the air (i.e. make it colder) and thus drastically reduce the air pressure on a given surface.  Then, the pressure from the atmosphere and friction would cause an object to be "stuck," much in the same way plungers can stick to a wall.

 

To understand how this is implemented on Roshar, we might claim that the ideal gas law is a consequence of Spiritual energy investment.  Heating up a gas stores energy in its Spiritual component, and this causes it to take up more room in the Physical realm.  So now we understand "how" the ideal gas law works, as opposed to "why."

 

What is the takeaway from all of this?  Physics attempts to model the universe using mathematics.  Whwne explaining phenomenon, we don't often consider "why" a given physical law is true.  The statement that "physics is the same in the cosmere as it is on earth" means that the phenomenon obey the same sorts of mathematical relations.  Why those relations are true is another question entirely.  On earth, we don't know why physics is the same in all inertial reference frames.  In the cosmere, there might be some Spiritual or Cognitive reason that this is the case.  That doesn't, however, change the nature of the mathematical equations that describe phenomenon.  What we want to understand is how the physical laws from our universe arise from the nature of the cosmere.

 

Thanks for reading!

 

Note: Understanding "why" laws work in our universe is actually a very interesting question when things go wrong.  This is how we develop new and more complicated theories for the underlying physical laws.  However, all this does is change current "why" for "how" and generate new "why."  So I do not want to imply that the "why" questions are useless, only that in the cosmere this sequence terminates at "Brandon said so." 

 

Source: I'm a theoretical physicist.

 

 

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The atmospheric pressure Surge can be understood in a similar toy model.  Ideal gases (and their interacting counterparts) shrink in volume when they are cooled down.  The atmospheric pressure Surge then could work in the following way: the energy contained in the Stormlight is used to remove thermal energy from the air (i.e. make it colder) and thus drastically reduce the air pressure on a given surface.  Then, the pressure from the atmosphere and friction would cause an object to be "stuck," much in the same way plungers can stick to a wall.

 

WoR spoilers:

This doesn't explain why Kaladin is capable of ignoring his own Pressure. You'd also expect people stuck on walls to get cold. Neither happens. I am aware you're not claiming that they're correct, but I think you're incredibly far off in assuming that the Surges will act like real-world things.

 

The Hamiltonian in quantum physics implies conservation of energy. This is fundamentally at odds with how Investiture seems to provide constant energy, and Iron Ferrings and so many other things. You can't have them and have quantum mechanics be the same in the Cosmere.

 

Sentience arising from Investiture and not neural connections (or whatever other methods exist) plainly means that humans are not the same in the Cosmere. They can't be without Brandon making up an over-convoluted billion line system of physics that just happens to replicate neural activity and then hooks it up to actual people's brains. He's just declared that Investiture makes people act the same as they do in the real world, which is cool. No need to look deeper there. Shallan's Memories imply that memory works on an entirely different system in the Cosmere; humans should have different 'memory speeds' in the Cosmere because of this, though I expect Brandon will just declare that it's the same as anyone in the real world.

 

Time bubbles break everything. I don't feel any need to expand on this point.

 

At a fundamental level, the Cosmere is just not compatible with real-world physics. Brandon is not a theoretical physicist, so I do not believe there's any need to 'interpret' his WoB on the Cosmere having the same physics as the real world: he's mistaken. The Cosmere will not act the same way as the real world.

 

I expect that most of the Cosmere acts similar to the real world, and that there will be atoms if people care to look that deeply into their world, but the entire Cosmere is at odds with quantum mechanics. I don't believe Brandon has figured out mathematical rules to form a basis of the Cosmere and used them to determine what the Cosmere looks like; I believe he decided it would be similar to the real world, and then worked backwards and made up the Realms and has fuzzily decided that everything works.

 

Which is fine. He writes books. I don't expect there to be actual mathematics underlying the realms that could allow us to figure out how much Stormlight is needed to Lash something based on Investiture stored in ironminds (no matter how much I'd like this, it's an impossible task). I expect Brandon is just working on an intuitive level on that, and just does whatever seems to make sense. To his credit, he has a nice underlying system with everything with Realmatics, but I don't expect to find much math dictating what the smallest size of Hemalurgic spike is required to fully take a Lerasium Mistborn's abilities. He's just going to decide that as he goes because there aren't really 'underlying laws' in the Cosmere (well, there are laws for some things, but not all things). And whatever underlying laws there are, he can change them at any time if he finds contradictions.

 

The Cosmere will look and seem like the real world, but everything will not follow the same mathematical relationships. It'll just be very convincing at looking and seeming similar because Brandon says it is. You can't take the real world, and say 'okay, everything is the same but now there's Investiture so I can break the conservation of energy' and still have the same fundamentals. The universe is too interconnected at a deep level for that. The same thing that causes your hands to warm up when you rub them together is responsible for your cells being capable of extracting energy from food. The fact that light exists is naturally connected with the conservation of energy. If you change conservation of energy, you change everything.

 

In summary, I feel there's no need to reconcile his WoB with anything. All he's saying is that we can expect to find most everything will be similar to the real world if we don't look too closely. If we do look closely, the relationships will be different, or else they'll be the same because Brandon says so (not because there's any underlying physics in the Cosmere).

Edited by Moogle
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I was going to post because (so far as I know) I'm the ur-example of "the laws of physics are Spiritually based!", but I don't know any real physics of note, so I'll just sit quietly in the corner here.

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First and foremost,

 

The Hamiltonian in quantum physics implies conservation of energy.

 

is blatantly false.  "Conservation of energy" is a loaded statement that changes its definition depending on what system you are working with.  In general relativity, "conservation of energy" is the statement that the metric does not depend on time.  Note that in our universe, this is not the case and so there is no strict notion of energy conservation in this way.

 

In quantum mechanics, energy is conserved if and only if the Hamiltonian is time-independent.  However, even with a time-dependent Hamiltonian, everything still works fine.  Quantum mechanics can easily accommodate systems where you pump energy into the system.  As the most basic example, when you turn on a light to illuminate a surface, the atoms making up the surface have a constant influx of energy and then re-radiate.  There is no notion of "conservation of energy" here yet we can easily describe this using time-dependent perturbation theory.

 

If you would like to learn more about quantum mechanics, I highly recommend Griiffiths' book on the subject.  He covers all of this very nicely.

 

Time bubbles break everything. I don't feel any need to expand on this point.

 

What about time bubbles?  Also easy, I considered posting an independent theory about how these could work.  The idea is simple - we have a spherically symmetric distortion to the metric that looks like a plateau.  Outside and inside, you would look down at your wristwatch and see time move normally.  But if you try to observe events happening through the bubble, you have to take into account the curvature at the bubbles edge and this would account for the time-speed discrepancy.

 

In fact, this is very similar to what happens as someone approaches the event horizon of a black hole (assuming there are no firewalls).  The observer outside sees time flow slower and slower for the person that falls in to the black hole.  You would need to tweak the metric a bit (unfortunately, I am not a relativist and there can't whip up a quick solution) but it accomplishes the same thing.

 

Such examples of funky metrics exist, and in fact one of the easiest ways to do FTL does something similar to a time bubble.  In our universe, such things may not be physically realizable without huge energy costs, but if you can get around that we would have FTL.

 

If you want to learn more about general relativity, Sean Carroll has an excellent book.  I admit, however, that understanding the Alcubierre metric is very difficult.

 

Sentience arising from Investiture and not neural connections...

 

This is not physics.  There are no known models for human consciousness from first principles.  For all we know, Brandon could be writing non-fiction about this part.  As such, this does not fall under the scope of my original post, which was to make sense out of physical laws based on Realmatic interactions.

 

This doesn't explain why Kaladin is capable of ignoring his own Pressure.

 

We know all things have three components - Physical, Cognitive, and Spiritual.  When a Windrunner infuses an area with the intention of sticking things down, it could be that he has to specifically set it up so that he can be affected by it.  Otherwise, it "knows" in some fashion not to stick him.  An you would be surprised at how even a small pressure differential (and thus small temperature change) will create a proper vaccuum.  When you put food in tupperware and seal the lid, you create a small vacuum.  But you don't see a noticeable difference in temperature because the change is so tiny.

 

Finally,

 

Brandon is not a theoretical physicist, so I do not believe there's any need to 'interpret' his WoB on the Cosmere having the same physics as the real world: he's mistaken.

 

Brandon tries very hard to make sure that his magic systems follow a set of rules.  Recall that he studied chemistry for a while in college and specifically has Peter Ahlstrom investigate the physicality of his ideas.  He goes to great lengths to ensure that his works are self-consistent, which is one of the things that makes his worlds so great.  This ensures that his worlds feel very "real" because we have some intuition for how things should behave.  And you're right, he probably doesn't have strict numbers on how much power you need to accomplish things, but the beauty is that you could sit down and calculate without having to make serious changes to the magic.

Edited by FirstSelector
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I love this theory! Mostly because I'm a physics person, though I only finished entry level (honors, but still) physics in college. I also want to add that Stormlight can be directly connected to energy by the fact that Lift converts food (glucose) into it. Maybe her body quickly breaks the molecules down, and the breaking bonds release Stormlight rather than thermal energy.

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There is a thread discussing Feruchemists as the best astronauts here

 

I proposed in that one that the Basic Lashing Windrunners perform is really just alternating their spiritual connection from the ground to the wall, which is what maybe be the underlying basis for gravity in the cosmere. Not sure if that's right nor not, but this little interlude from WoR makes me think I'm on to something!

 

WoR Spoiler:

Natural laws?” Syl said, finding the concept amusing. “Laws are of men, Kaladin. Nature doesn’t have them!”

“If I toss something upward, it comes back down.”

“Except when it doesn’t.”

“It’s a law.”

“No,” Syl said, looking upward. “It’s more like… more like an agreement among friends.”

He looked at her, raising an eyebrow.

“We have to be consistent,” she said, leaning in conspiratorially. “Or we’ll break your brains.”

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