
Are Physical Laws Inevitable? - chmaynard
https://www.math.columbia.edu/~woit/wordpress/?p=11513
======
raspasov
After reading a few blog posts and interviews with Peter Woit, I think I can
say he's definitely a little bit "fringe" as far as physics is concerned. He
does try to stick to the science (of sorts) but using some philosophizing he
makes critiques like here:

[https://blogs.scientificamerican.com/cross-check/why-
string-...](https://blogs.scientificamerican.com/cross-check/why-string-
theory-is-still-not-even-wrong/)

"This is however a straw man argument: the problem with such research programs
isn't that of direct testability, but that there is no indirect evidence for
them, nor any plausible way of getting any."

Sure, we might not have a plausible way of testing it today but that doesn't
mean there won't be in the future. 2000 years ago people were on the right
track that the Earth is round but couldn't "test it" but going around it. I'm
sure the prospect of going round the earth back then seemed as distant as
testing a multiverse today.

He also calls other reputable physicists "pseudo-science", which is aggressive
and over the top.

All in all, he doesn't seem to present a logical critique beyond "it's not
testable", all while using circular logic that "not being testable" is
sometimes beneficial:

"Many ideas that are "not even wrong", in the sense of having no way to test
them, can still be fruitful, for instance by opening up avenues of
investigation that will lead to something conventionally testable."

~~~
tsimionescu
> Sure, we might not have a plausible way of testing it today but that doesn't
> mean there won't be in the future. 2000 years ago people were on the right
> track that the Earth is round but couldn't "test it" but going around it.
> I'm sure the prospect of going round the earth back then seemed as distant
> as testing a multiverse today.

But there lies the problem: people 2000 years ago had a very clear idea of how
they could test their round earth idea, it just wasn't technically feasible.
Even worse for your point, they did quickly come up with experiments and
proved pretty definitively the shape and general size of the earth, based on
ships going past the horizon and others.

There have been many physical ideas with no hope of testability throughout the
ages, and many of these have turned out wrong. Aristotle believed, and
physicists agreed, that all objects have a natural place which they tend to
move to, so apples falls down, but steam rises up.

As far as I know, there are not even thought experiments about how we could
tell whether there is a multiverse, or for many (but not all) aspects of
string theory. This is not an engineering problem (its way out of our league
to implement), it's a theoretical physics problem (we don't know whether there
is a way to tell, there may very well not be one). It's like the difference
between people in ancient Greece imagining a high-speed car, versus building
faster-than-light travel.

~~~
raspasov
I am not a physicist, but one can definitely come up with thought experiments
about testing the multiverse. One could imagine creating a universe in a lab
"from nothing" since there's a hypothesis that the energy of a universe could
be zero (see [https://en.wikipedia.org/wiki/Zero-
energy_universe](https://en.wikipedia.org/wiki/Zero-energy_universe) and
[https://en.wikipedia.org/wiki/Inflation_(cosmology)](https://en.wikipedia.org/wiki/Inflation_\(cosmology\))).

Now, we might not be 2000 years but perhaps 20,000 or 20 million years away
from coming up with the technology and breakthroughs required to do this. In
the grand scheme of things, even 2 billion years is not that much.

One big difference with Aristotle's apples, steam ideas, etc is that there's
very solid mathematical foundation under string theory/multiverse that to a
great extend agrees with existing well tested theories like quantum mechanics
and general relativity. That does not make string theory/multiverse true but
it at least leaves the possibility open. Aristotle's ideas that turned out
definitely wrong were born out of pure philosophizing and were little better
than pure fiction.

~~~
tsimionescu
Creating a new universe inside our own would not prove that universes other
than our own and the newly created one exist. Sure, it proves that it is
possible, but that would not be surprising. The argument is that we have no
physical argument that can either prove or disprove the existence of extremely
distant other universes, and simply creating one would not move that debate in
any direction at all.

This goes even more for the many - worlds interpretation of quantum mechanics.

On the last point, I do agree. I realize how it sounded, but I didn't mean to
imply that string theory is as plausible as Aristotle's physics. Still, it is
somewhat intellectually dangerous to believe in a theory that does not make
testable predictions.

~~~
perl4ever
"a theory that does not make testable predictions."

When people use this phrase, I think they are often referring to a theory that
"does not make testable predictions _that are different from the mainstream
accepted theory_ ". But I wonder to what extent new science requires looking
at familiar things differently _first_?

~~~
tsimionescu
Well, if we got a new theory that explained exactly the same facts as QM
without making new untestable predictions, and if that theory had some
desirable properties such as being more intuitive or being mathematically more
desirable, the new theory would hopefully be embraced.

However, string theory does make significant new predictions, though a lot of
them are untestable at the moment. The problem with this is that if you accept
string theory you have to accept, for example, that there are 10 spatial
dimensions, though we can't notice them in any way. You may have to accept
that there exist many (or an infinity) of other universes that are too far for
us to be able even theoretically to notice.

The meat of the issue is this: physics is ultimately concerned with describing
what the real world looks like and how it works. When evaluating a physical
theory, we shouldn't care just about its self-consistency, but also about
whether it is likely to be a good model of the physical world. And to be able
to tell, we need to test _all_ predictions of this theory, especially the
counter-intuitive ones, and check whether they actually describe the real
world, not simply whether they are theoretically possible. Sure, if one or two
new predictions remain elusive, but we've checked all of the others, we may
have good reason to believe the theory (e.g. we had good reason to believe
general relativity even though it predicted black holes even before we were
able to observe the first black hole, because it made so many other
predictions that we did confirm, and that no other theory could describe).

A good example of a theory that is still floating around, that doesn't make
new predictions compared to QM, but that is more desirable in other ways is
the DeBroglie-Bohm pilot-wave theory of QM. It's not yet complete (it can't
account for all aspects of QM), so there is still a good chance it is simply
wrong. But, IF it will be able to account for all of QM, even without making
any new predictions of its own, it might become a much more popular new
theory, on account of simply being more intuitive (no more particle-wave
duality, no more randomness, and particles would have properties even before
you measured them; note however that it does have non-locality, so it's not
all roses).

------
keithnz
I'm no expert, but it seems likely to me that there should be an infinite
amount of mathematically consistent "theories" to describe a given system. Iff
the "theories" have no more predictive power than the rules of the system
itself ( they may make predictions but unless they are testable they could
describe non existent things and you wouldn't know).

~~~
Taniwha
Got to be careful there, when someone pointed out to Einstein that his theory
of Relativity predicted wacky singularity things he scoffed ... we call them
"black holes"

------
chmaynard
Nima Arkani-Hamed was one of three theoretical physicists featured in the
wonderful 2013 documentary "Particle Fever".

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

------
petschge
The article in Quanta magazine has also been discussed on HN:
[https://news.ycombinator.com/item?id=21743847](https://news.ycombinator.com/item?id=21743847)

------
mirimir
This is the best bit, from the comments:

> Actually, in many of his talks he [Arkani-Hamed] explains clearly the
> motivation for the hype: it’s to motivate himself.

------
rrauenza
I see the article mentions Sabine Hossenfelder -- I had just started watching
some of her videos on YouTube. She's a wonderful presenter.

She's also a talented singer and has some music videos on her channel as well.

~~~
djaque
Be careful with her videos. While she does have some good content, Sabine has
an agenda to push with respect to big science and I've seen at least a few of
her articles on projects I'm familiar with that are well within conspiracy
theory territory.

See, for example, her blog post and video on LIGO where she makes it seem like
the researchers committed fraud and fabricated the whole detection of
gravitational waves. My explanation of why this is dishonest here: [1]

Unfortunately, this is really harmful because she's coming from a place of
authority and spreading the lie that big science is bending the truth when it
comes to their discoveries. You can see this reflected in her audience and her
video comments are full of climate deniers and others that want this to be
true thanking her for exposing, in their words, the so called "quack-a-
demics".

[1]
[https://news.ycombinator.com/item?id=21448974](https://news.ycombinator.com/item?id=21448974)

~~~
knzhou
It's worse than that. She made a reasonable blog post highlighting somebody's
doubts of the LIGO response, got a reasonable response from LIGO, and
acknowledged that she was satisfied with it. That was a perfectly fine
scientific dialogue.

Then months later, she made a much more conspiratorially-toned blog post
raising no new issues, but which linked only to her original post as proof
that "doubts have been raised", not acknowledging the LIGO response, and
generally painted scientists as liars. That is just incredibly disingenuous,
and I see no motivation behind it besides wanting to fire up a popular
audience.

~~~
djaque
Yes! To be clear it is the second blog post/video that I am criticizing.

------
ncmncm
Simple answer: No.

Anybody who says yes is selling something. "Maybe" is not necessarily
dishonest.

------
louis_pasteur
Physical laws work only in the physical realm. They break down the moment you
get into the realm of "thoughts and feelings". There are other deeper realms
too which advanced buddhist meditators have experienced and talk about.

------
cscurmudgeon
Anyone who claims physical laws are inevitable in the sense of the Quanta
article should please take a small course in formal logic.

------
QuanticSausage
Yes.

edit: punctuation

~~~
QuanticSausage
By definition a physics law is inescapable. If that law can be circumvented,
then there are deeper physical laws at work. Don't be conceited, nothing can
be absolutely relative. If everything is relative and it's an illusion, at
least the existence of illusions is objective.

------
yters
Materialists just trying to avoid the implications of Wigner's argument.

~~~
ithkuil
What would the implication be?

Do you assume that it's absurd to consider that a conscious being is really no
different than any other memory equipped machine and thus can be in a
superposition state like anything else without necessarily "feel" anything
special about it?

~~~
yters
Considering no machines are conscious, yes, it is absurd.

~~~
ithkuil
No machines _we know of_ _in the present_ are conscious. Our ignorance about
whether that's possible or not is not a proof it's not possible.

Besides, why would it matter if the observer is conscious or not?

Our psychology is biasing our reasoning about these thing, leading us to
attribute something magical to the process that make us "us". It's
understandably utterly disconcerting to lose the ground under the sense of
self that we inhabit, but that's not a reason to discard, a priori, a line of
questioning reality. I know it's hard to shake this uneasy feeling off, even
for non-religious people.

But let's imagine for a moment that whatever the substance of our
consciousness actually is, it can be forked/cloned into copies of itself that
no longer share the identity after having been cloned, yet retain the memory
of past events (external or internal to itself). I realize this is a bold
assumption, but arguably less contentious to accept than whether machines can
ever become conscious (perhaps because it sidesteps our innate aversion for
outgroups, non-biological entities being extremely outgroup).

Now, imagine you fall asleep and get cloned in two, and the two resulting
persons are put, still asleep, in two rooms (room 0, and room 1). After an
hour they wake up. They both have copies of your memories and both have a copy
of whatever-the-thing-that-holds-consciousness is (soul, matter, different
kind of "stuff", not really relevant, as long as it's not incompatible with
the "cloning postulate"), so in a way, they both think they are _you_; they
feel a direct continuity with what they were before falling asleep and getting
cloned. They'd have no way to tell which of the two entities they are though.

Imagine now being one of them. You get out of the room and peek at the room
number on the outside of the door. Which number will you see?

~~~
perl4ever
Why would a shared past equal a shared future? I mean, you don't treat twins
as though they are a single person, right?

~~~
ncmncm
Some people do. Dress them the same, even.

~~~
perl4ever
I would say treating them the same is an affirmation that they are different
people. If they really were the same person, nothing would have to be done
twice.

------
swiley
There are physical laws but if you watch people they always find ways around
it given enough money and time. Space travel via rockets is a nice example of
that. Even the rocket equation itself has been circumvented via solar sails
and magnetic propulsion.

You might think you can rely on something as simple as thermodynamics but if
you are you’re going to have to be absolutely anal about where you draw the
system boundary. People are really really good at getting work out of nearly
anything. Don’t forget the planet is warmed by the sun and that you can just
walk outside and use that for work.

~~~
perl4ever
It seems to me that you are not talking about violations of physical laws, but
violations of the rough, but wrong, approximations of physical laws that
people use in some contexts.

It doesn't seem startling or interesting that people continually find ways
around rules that are not rules.

~~~
swiley
Right they’re not violated, but my point is that they’re almost never the
impassible barrier that people make them out to be.

It’s not that the rough approximations are wrong it’s that people focus too
much on one or two ways of doing things (using atmospheric air as a reaction
mass to fit my first example) until someone creative and knowledgeable enough
finds a new way to do them (rockets then.)

