
There Are No Laws of Physics, There’s Only the Landscape - digital55
https://www.quantamagazine.org/there-are-no-laws-of-physics-theres-only-the-landscape-20180604/
======
ifdefdebug
For those like me who are not too happy with this kind of "science" (for one,
the title is worded in a way that makes this highly controversial view of
reality sound like state of art in physics), "Not Even Wrong" [1] by Peter
Woit is a great read for multiverse skepticism (mostly centered on "string
multiverse", not quantum "many worlds").

[1]
[https://www.math.columbia.edu/~woit/wordpress/](https://www.math.columbia.edu/~woit/wordpress/)

~~~
kbutler
All models are wrong, but some are useful. -- George Box

And some are not useful except as a mental exercise. Maybe they will become
useful at some point, maybe not.

------
FailMore
This feels off to me. Einstein’s process did not come from the mathematics,
but from an idea of what was happening. This enabled a great number of odd
predictions which were verified (the Sun would bend the visible pathway of a
star, there would be gravitational waves, etc...). String Theory feels like a
theory which is starting at the wrong place. Not an idea of what process is
happening and then seeing if the results fit, but an attempt to connect all
the results into a theory. Pas bien por moi!

~~~
WaxProlix
> String Theory feels like a theory which is starting at the wrong place. Not
> an idea of what process is happening and then seeing if the results fit, but
> an attempt to connect all the results into a theory.

Are you saying that it doesn't make any predictions (and is therefore
unfalsifiable)?

~~~
nonbel
>"Are you saying that it doesn't make any predictions (and is therefore
unfalsifiable)?"

As I understand, its the opposite. String theory "predicts" any and every
possible observation, then they cherry pick whatever predictions are already
accepted as fact to say there is evidence for the theory.

~~~
Retra
Sure, but regular quantum mechanics does the same thing. It's under-
constrained and allows for too many possibilities. So you assume that the
observations wrought by Newtonian physics must be valid and use that to
constrain the theory down to something that can be useful.

The difference is that the string model doesn't (yet) have any observations
which we could use to constrain it in an analogous manner. But in studying it,
one would hope to find areas of the theory that indicate where those
observations could be made.

The point being, it is not so simple to just look at string theory and say you
can _a priory_ determine it is flawed or wrongly motivated. That same kind of
reasoning would likely have prevented Planck & Einstein from starting quantum
theory.

~~~
nonbel
>"observations wrought by Newtonian physics"

I'm not sure what this means. Is it different from just making an observation?
Eg, "this light in the sky is of this color at that location", or "this object
drops at that speed".

~~~
auntienomen
It just means that we need the correspondence principle to find useful quantum
mechanical models. Without that, you're just talking about algebras acting on
Hilbert spaces.

------
ghkbrew
The article says that one of the attractive qualities if string theory is that
it has no free parameters. But then says that the particles a forces of the
standard model are determined by the number and size of extra dimensions.
Those sound an awful lot like free parameters.

Can someone with more than a passing familiarity with the field explain?

~~~
auntienomen
Normally in a physical theory, you have some equations describing the dynamics
and you go looking for solutions to these equations. The dynamical equations
may have some parameters (such as the constant G in Newtonian/Einsteinian
gravity), and then there are usually additional parameters required to
describe the solutions (such as the mass M of the gravitational field source).

String theory has the unusual property that its dynamical equations don't have
free parameters. The dynamics is apparently unique. But there are many many
solutions to these equations, and so there's a huge space of parameters from
that. In particular, if you go looking for ways of embedding the Standard
Model in string theory, all of its dynamical parameters (like the electron
mass and Newton's constant) are realized as solution parameters.

~~~
kolpa
Can I make Newtonian mechanics into a dyanically 0-free-parameter theory by
stating that F == gMm/r^2 , where g is a solution parameter ("the gravity of
the universal landscape" ?

~~~
auntienomen
You can do this -- and indeed, promoting constants to fields is a common
technique in the analysis of field theories. But it's cheating if you say the
constant is dynamical and then don't say what the dynamics is. In field
theory, you have to make additional choices here, and there are a lot of
additional parameters that enter.

In string theory, you don't have to/get to make a choice at all. The dynamics
is uniquely determined. It's not exactly a free lunch, but it's a very unusual
feature for a physical theory.

------
tabtab
Is it just me, or does string theory seem like epicycles all over again: if
you throw enough center-intersecting circles into the engine, it can emulate
just about any observed movement of objects in the sky; a sort of "circular
regression" in the same way that piling up polynomials gives us Polynomial
Regression. String theory is like "dimensional regression". Regression is a
powerful tool, but is NOT designed to directly "explain" phenomena, only
emulate them.

Newton et. al. came along and gave us a much simpler model of gravity and the
solar system such that we could toss out the messy nested circle models. (We
still can't say that Newton's model is fully "right", but it's certainly
simpler.)

~~~
jcranmer
Well, string theory is kind of the anti-epicycle. The epicycles in Ptolemaic
astronomy were added to make the math conform to reality, but people didn't
believe that the planets actually moved in epicyclic motion. Superstring
theory started from the opposite standpoint: the Standard Model is math that
works out, but the theory is messy, so superstring theory sought to make an
"elegant" theory that checked out with the math... and ended up with a theory
that is so general it can't really be disproven.

The end result is the same, but the paths to get there are completely
different.

~~~
whatshisface
String theory was originally exciting because it had a graviton that worked,
and to my knowledge it is really the only theory that contains both the
standard model and gravity. LQG is not yet at the point of reproducing 3+1
space as far as I know. So, here's my proposal: saying that the earth orbits
the sun in a universe where QED also is true isn't proof of string theory, but
it does falsify the standard model and so far to my knowledge most of string
competition.

~~~
jcranmer
> but it does falsify the standard model and so far to my knowledge most of
> string competition.

Not really. The Standard Model makes no prediction about gravity; it makes no
claim to. Gravity is so weak that it can be ignored almost everywhere where
the other forces come into play: the contribution of gravity compared to
electrostatic attraction on the atomic order is smaller than 0.01ZWD is to
world GDP... for all of human history. The places where you have to worry
about gravity and the other forces at the same time are places where we have
precisely no ability to make observations that could distinguish between
theories.

------
monktastic1
I'm reminded of this beautiful quote from Chris Fuchs, regarding his advisor,
the great John Archibald Wheeler:

> [Wheeler] would say things like, “In the end, the only law is that there is
> no law.” There’s no ultimate law of physics. All the laws of physics are
> mutable and that mutability itself is a principle of physics. He’d say,
> there’s no law of physics that hasn't been transcended. I saw this, and I
> remembered my joke about how the laws of physics must be wrong, and I was
> immensely attracted to this idea that maybe ultimately there actually are no
> laws of physics. What there is in place of laws, I didn't know. But if the
> laws weren't 100 percent trustworthy, maybe there was a back door to the
> stars.

~~~
maskedSlacker
This sounds like semantic befuddlement (though, not on Wheeler's part; he was
just engaging in wordplay).

Physical laws are not 'laws' in the sense that nature is required to abide by
them. They are simply features of natural behavior that have been so
overwhelmingly observed that we treat them as axioms.

An example of this is the 'law' of conservation of mass. Strictly speaking,
nature does not follow this law. Nuclear reactions and subatomic interactions
do not conserve mass. They conserve other quantities, but not mass in and of
itself.

The idea that there is no ultimate law of physics is not novel or interesting.
It's obvious on its face, unless you do not properly understand what 'law'
means in the context of physics.

~~~
goatlover
Law of physics implies a casual relationship in nature. Saying there are no
laws of physics is saying nature is acausal. B always follows A for no reason
other than it just happens to do so in our universe. This is the Humean view
of causation, which is constant conjunction instead of there being a reason
that A results in B.

The plus side is that you don't have to deal with causality, which is a tricky
concept. Hume persuasively argued that causality is neither empirical nor a
result of logic. The downside is that all necessity is totally arbitrary. It
just so happens ... As such, there is no reason for anything we observe. Just
descriptions.

~~~
gowld
Causality is separate. Laws of physics (conservation/symmetry) are
constraints, not causality.

"a+b=7" implies that "a=3 implies b=4", and "b=4 implies a=3", without regard
to what causes the other, or what caused the law to be true.

~~~
goatlover
By implies, I mean that the laws of physics are approximating the actual laws
of nature, which would be causal.

~~~
jhanschoo
You are postulating here a priori that causality governs the movement of the
universe. That is a philosophical position on how to interpret physical
observation, but whereas archetypal temporal cause-and-effect phenomena is
frequently observed, there are yet many physical phenomena that you and I
regard as fact don't have obviously observed temporal causes. For example, we
observe the Big Bang as well as the accelerating expansion of the universe,
but don't have good explanations for their temporal cause. And everything in
the universe is temporally caused by the Big Bang...

So what I'm trying to say here is that your claim here that causality governs
the actual laws of nature is suspect, both because your comment has not been
elaborate enough to specify what you mean by causality, and because one of the
most popular notions of causality, i.e. temporal causality, seems, to a first
approximation, not be a good model of the observable physics: it postulates a
temporal cause for the big bang, but no time prior to the big bang is
observable.

------
lossolo
There's a great quote from the X-Files by Scully on this topic.

"Nothing happens in contradiction to nature, only in contradiction to what we
know of it. And that's a place to start. That's where the hope is."

------
superqd
This is the one major reason I lost most of my desire to continue grad school
(I was studying astrophysics). I chose physics specifically because I wanted
to understand the universe. The way I thought of it was that I wanted to lift
the hood of reality and see how things "really" worked. As a kid, I'd read a
number of books on science and had heard of a quest for a Theory of
Everything. I'd decided this was a quest I wanted to go on. I thought of it as
the most worthy singular hidden treasure and I was willing to devote my life
to digging for it.

But over the course of my undergrad, and hours debating with friends, and
reading even more, I started to get an uneasy feeling. I decided to go to grad
school, partly, because I still held on to the belief that there really was
treasure at the end of that rainbow, and that we really could, if we were
clever enough, "figure out" how things "really" worked. But, in grad school,
it just continued to dawn on me how impossible it was for there to be only One
True Theory. One way I thought about it was to regard physics as a program.
Even if there were separate theories for different scales, or domains, it
didn't matter, you could still regard the whole knowledge base as a single
program and the scale and domain, along with physical observables, as inputs
to the Physics Program. The output would be predictions for the state of the
universe (or some subset, it didn't matter) at some later time, i.e., it would
predict later observables' values.

The thing was, I had a hard time finding any logical justification for why
there _had_ to be only _one_ program that could take in the known inputs and
produce the known outputs. That is, there was no way to logically prove that
there could _not_ be multiple equivalent programs that could produce the same
output given the same input. I.e., there was no way to logically justify the
notion that there could only be One True Physics. That is, the treasure I
believed I'd be digging for, didn't _not_ exist, it was just that there was
more than one treasure, and anyone could find their own.

This thought diminished some of the romance, so to speak, of the Quest for
Truth, so I lost interest, for a time. Enough to stop taking grad school
classes and just start working (coding). Maybe one day I'll create a program
of my own.

~~~
lioeters
Your comment stayed in my mind, about the (maybe futile) quest for the "one
true theory". Today I was reading an article [1], and a passage reminded me of
what you were talking about:

Schrödinger’s theory proved easier to use than Heisenberg’s, in part because
it is more intuitive. Furthermore, first Schrödinger and then Paul Dirac
proved that the two theories are equivalent. In physics any two theories that
make precisely the same observable predictions are observably equivalent. And
one of the predominant philosophical views of the age — logical positivism —
held that any two observably equivalent theories are really one and the same
theory.

...

Einstein demanded a clear and comprehensible account of what is going on in
the physical world — at all scales — in space and time. Bohr thought that the
key to quantum mechanics was the realization that no such thing could be had.

[1] [http://bostonreview.net/science-nature-philosophy-
religion/t...](http://bostonreview.net/science-nature-philosophy-religion/tim-
maudlin-defeat-reason)

------
tw1010
There's a quote, in I believe one of Greg Egans books, about the idea that the
probable end state of physics will be just a bunch of isomorphic theories,
which I wish I could find right now.

~~~
westoncb
For understanding why that might be, I find this to be an elegant little
example: take a pattern of black and white stripes; is it white with black
stripes, or is it black with white stripes? The two formulations are identical
in consequence of what they describe, even though they frame things inversely.
(Of course this is just a metaphor to hint toward something in the nature of
language, and is not really a deep scenario if you dig into it.)

It seems likely that the descriptions we formulate in physical theories work
because they create a pattern which is isomorphic to patterns we extract in
physical measurements—but there's something in the nature of the universe
and/or language so that there tends to be many ways to create some linguistic
thing which produces exactly the same pattern.

~~~
whatshisface
That's actually one of the main ideas of positivism: that if two theories lead
to the same physical predictions, they are the same theory. When positivism is
presented as "every true thing is empirically knowable" it sounds kind of
shaky, but if you instead go for, "you can't tell the difference between two
internally-consistent claims unless you compare them with the world," then it
sounds a lot more likely to be true.

~~~
goatlover
> "you can't tell the difference between two internally-consistent claims
> unless you compare them with the world," then it sounds a lot more likely to
> be true.

But only if it's the case that we end up with more than one theory which
explains the phenomena equally well. That doesn't seem to be what ends up
happening. We don't have an equivalent to GR, QM, Evolution, or any other well
established, large scale theory.

Positivism sounds closer to math than it does science. And that's because
nature is a certain way, which means you probably can't have equivalent
theories at sufficiently granular levels.

~~~
westoncb
My understanding is that there are multiple precisely equivalent formulations
of classical mechanics (Newtonian mechanics being one of them, but then
there's e.g. Lagrangian mechanics[0] and other more exotic things).

Perhaps that doesn't cross your threshold for 'sufficient granularity'—but it
took quite a bit of time to find the alternate formulations in classical
mechanics (after Newton I mean), so just because we don't yet have them for
certain more modern theories doesn't mean they aren't forthcoming.

Also, I'm pretty sure there are at least very nearly equivalent formulations
of QM, e.g. the de broglie pilot wave stuff (often termed as an alternate
'interpretation', but my understanding is that the differences extend even to
the level of mathematical formulation, and are not just some detached
reflections on the 'meaning' of the theory or whatever.

[0]
[https://en.wikipedia.org/wiki/Lagrangian_mechanics](https://en.wikipedia.org/wiki/Lagrangian_mechanics)

~~~
whatshisface
> _so just because we don 't yet have them_

I think the strongest argument for positivism is that you can generate
arbitrarily many trivial "different but the predictions are the same" theories
from _any_ parent theory just by doing algebra. You can also generate
arbitrarily many "the predictions are slightly different but our present
experiments can't resolve it" theories from a parent theory by littering it
with new, small constants and tiny interactions. Occam's razor will lead you
astray about that, too: most of modern physics was at one time a small
constant or a tiny interaction.

------
yedawg
Physical theories imply physical laws and consistent variables which require
consistent math and hard scientific research; There is no escaping that. To
say that physics is like a "landscape" is like comparing scribble of a stick
man to a Picasso. There is a lot we don't know about the universe, I think its
time for writers and physicists to get on board with that and analyze the shit
out of their vague and opaque understandings before hitting the enter key.

------
skissane
Multiverse theories like string landscape, eternal inflation, or many-worlds
generally have this property: Almost anything that possibly could happen will
happen in some universe. But, it is said, that some universes are more
frequent than others. From local observations we infer the global laws of
physics, which tell us the relative distribution of different types of
universes. But, surely there will be some "deceptive" universes, in which
(purely by chance) observers are always mislead as to what the actual laws of
physics are. Experimental error always goes in the same direction, such that
the true laws of physics are never known, and those observers rationally
believe in false laws of physics instead. Now, an observer in such a universe
will rationally infer a given probability distribution of universes based on
their local observations, but the distribution they infer will be completely
wrong. My question is: how do we know we are not in such a universe? To say
such universes must be exceedingly rare (even though existent) is sort of
circular, because our conclusion they are rare is based on our idea of the
global probability distribution, but in order to validly make the inference
from local observation to global distribution we have to assume we are not in
such a universe. But, if we can't know we are not in such a universe, then we
can't know that some universes are "more likely" than others, which is a
central claim of these theories, and what distinguishes them from David Lewis'
modal realism. This is why I think all such "multiverse" theories should be
rejected.

------
warmfuzzykitten
But...

[http://bostonreview.net/science-nature-philosophy-
religion/t...](http://bostonreview.net/science-nature-philosophy-religion/tim-
maudlin-defeat-reason)

------
danbruc
Off-topic question that seems to trivial to take to Stack Exchange but I am
struggling to find an answer to, maybe a physicist comes by and can provide an
answer or relevant reference.

Let's take a spin 1/2 in the superposition state |0> \+ |1> ignoring
normalization and then add the rest of the universe including a measuring
device, an observer, and all the other bits and pieces of the environment.
This state then undergoes unitary time evolution past the point where we
measured the spin and the observer had a look at the measuring device.

It now seems to me that if the final state is a definite |0> or a definite
|1>, then this measurement outcome must already have been present in the
initial state, not necessarily as hidden variables of the spin but somewhere,
for example in the micro states of the measuring device. If the final state
could indeed be either |0> or |1> independent of the initial state, time
evolution would not be unitary, it would not even be a function of the initial
state.

The only other option seems to be that the final state is still a
superposition and we have to reach for something like the multiverse
interpretation to reconcile the fact that we indeed observe a definite final
state. So what is the correct or at least common way to think about this? Time
evolution is only approximately or sometimes unitary? The measurement outcome
is, similar to decoherence, determined by the environment? The final state is
still a superposition? Non of those seems to be a particularly attractive
choice. Or did I somewhere make a stupid mistake?

~~~
Steuard
I just finished teaching a Jr/Sr undergrad Quantum Mechanics course last
semester, so I'll take a stab at answering this.

There are two approaches to answering this question. One of them invokes the
concept of "the collapse of the wavefunction" at the moment of measurement:
when an observer actually measures the outcome of such an experiment, the
universe probabilistically selects one of the possible outcomes as "true" and
proceeds from there. This "collapse" process is explicitly non-unitary. You
may ask, "What entities qualify as 'observers' to trigger collapse?", and the
answer is basically "It's not well-defined." As you might gather from that,
it's not clear to me that you can include an "observer" in this sense as part
of the overall wavefunction of the universe at all, though perhaps people who
have studied the foundations of quantum mechanics in more detail could give a
better answer.

The other option is pretty much exactly what you've described in your final
paragraph: you don't invoke "collapse of the wavefunction" at all, and the
final quantum state of the universe after measurement is indeed a
superposition of "|0> and observer who saw '0'" and "|1> and observer who saw
'1'". Because anything we'd call an "observer" will be a large, complex
system, there will very rapidly be a vast number of tiny, "pseudo-random"
differences between the two branches of the wavefunction, ensuring that there
won't be opportunities for the two branches to experience significant
constructive or destructive interference in the future: they'll evolve pretty
much completely independently from then on. (This concept is called
"decoherence", which you've made reference to, and I'm definitely not an
expert on it, but I'm told it's become quite important in research on quantum
computing.) There's still a probabilistic question of which branch of the
wavefunction a given observer might _experience_ (and understanding why _that_
happens is an enormously subtle question; I've seen some work by Sean Carroll
among others trying to make progress on it), but once a given observer has
measured a particular outcome to the experiment, the math of quantum mechanics
guarantees that they'll continue to measure consistent results after that.
This is more or less the Everett "many worlds" interpretation of quantum
mechanics.

As you might gather, I'm partial to the latter interpretation, in part because
it's where the math seems to most naturally lead (the first time I felt like I
really understood quantum mechanics was after a very math-heavy graduate
course taught by Robert Geroch), and in part because I've never been able to
make sense of what wavefunction collapse might mean (and never been happy
about its violation of unitarity).

~~~
danbruc
_As you might gather from that, it 's not clear to me that you can include an
"observer" in this sense as part of the overall wavefunction of the universe
at all, though perhaps people who have studied the foundations of quantum
mechanics in more detail could give a better answer._

I did some more reading and it seems that at least some try to do what I also
considered, try to attribute the randomness in the outcome to the randomness
and uncertainty in the initial state of the measuring device, observer, and
environment. This then raises the question why all kinds of measuring devices
produce the same distribution of measurement results if the concrete outcome
essentially only depends on the initial state of the measuring device. And
this also has the smell of a hidden variable theory where the hidden variables
are in the measurement device, would this be compatible with EPR?

I also took away some things to follow up on from your comments on Everett but
unlike you I don't really like multiverses and so this will have to wait for
some time. I however agree that Everett makes the most sense with regard to
completeness and consistency.

------
stcredzero
_The Map is Not the Territory!_

[https://wiki.lesswrong.com/wiki/The_map_is_not_the_territory](https://wiki.lesswrong.com/wiki/The_map_is_not_the_territory)

Another piece of widespread ignorance I've seen here on HN, is the treatment
of conservation laws as if they're baked into the fabric of reality. This
results in programmers making philosophical/cosmological arguments in
ignorance. As far as we know, conservation laws are not baked into reality.
Instead, they are very useful analysis tools which can take advantage of
symmetries. (Or near-symmetries.) Any given conservation law can disappear if
a given symmetry doesn't apply, but Noether's Theorem still remains.

[https://www.youtube.com/watch?v=04ERSb06dOg](https://www.youtube.com/watch?v=04ERSb06dOg)

If you want to see an example of how social media "bubbles" can impede the
dissemination of knowledge, note that I've actually been flagged on HN for
trying to explain this, apparently because someone misread this as advocacy
for perpetual motion machines. It is not! (Also, because I used <facepalm> \--
but when you're wrong, you're wrong, and when you're wrong and you think it's
clever, it feels worse.)

(That title, "The Map is Not the Territory" acts as a pointer to a series of
literary references.
[https://en.wikipedia.org/wiki/The_Map_and_the_Territory](https://en.wikipedia.org/wiki/The_Map_and_the_Territory)
)

~~~
kolpa
What does "baked into reality" mean? We can never know more about reality than
what we observe, and furthermore conservation laws are axiomatic --
conservation simply means that we are able to account for (almost) everything
we observe, in a consistent way. When conservation is broken, we name a new
form of energy, and (so far), we find that it can by accounted in a
consistent, predictable way. (Dark matter is an unsolved problem. Knowledge is
incomplete. That doesn't mean conservation is false.)

When it comes to fundamental science, a consistent map _is_ the territory.
"Map is not the territory" applies to simplifications that omit detail.

I don't see people trying to be "clever".

~~~
stcredzero
_What does "baked into reality" mean? We can never know more about reality
than what we observe, and furthermore conservation laws are axiomatic --
conservation simply means that we are able to account for (almost) everything
we observe, in a consistent way._

You said it right there. "Almost." We keep on prying and doing experiments,
and we can't find _any_ exception. If we've tried hard enough for long enough,
we can start to conclude that we're probably getting close to reality. If we
pry and we find it's "almost" then we know it's not baked into reality.

 _When conservation is broken, we name a new form of energy, and (so far), we
find that it can by accounted in a consistent, predictable way. (Dark matter
is an unsolved problem._

[Citation Needed] Yes, we still don't know what Dark Matter is, but do you
understand that dark energy is not dark matter, and the current model for dark
energy involves space expanding and more dark energy appearing due to the
space expanding? Citing dark energy is tantamount to admitting that
conservation of energy isn't universal.

 _When it comes to fundamental science, a consistent map is the territory._

Arrgh. You're getting your pointers mixed up here. A context where science is
the territory would be the study of Science, as in the philosophy of science.
When it comes to fundamental reality, Science is the map and fundamental
reality is the territory.

~~~
kolpa
Sorry, I should have said we don't understand dark energy yet.

In what sense does "fundamental reality" exist?

~~~
goatlover
That which gives rise to experimental results and perception. If you don't
think there's a real world responsible for those, then how do you explain what
we sense and the results from experiments? What makes the technology work?
God?

~~~
gowld
I surely don't know. That's metaphysics, not science.

~~~
stcredzero
_I surely don 't know. That's metaphysics, not science._

But you can clearly do science on the technology. People do this with high
degrees of success, developing theoretical models with high predictive
ability. It's called "reverse engineering." If you're going to retreat into
metaphysical mumbo-jumbo, that's up to you. The doing and the results will
speak for themselves, and no one will pay attention to the metaphysical mumbo-
jumbo obscurantists.

------
johnvega
This is fake news. Jump off a 10 story building balcony into a cement and see
if "There Are No Laws of Physics" or the title can be changed.

