Are Physical Laws Inevitable?
math.columbia.edu
math.columbia.edu
https://blogs.scientificamerican.com/cross-check/why-string-...
"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."
Fun fact: Eratosthenes measured the circumference of the Earth and the tilt of its axis around ~200 BC, by comparing the angles of shadows at two locations. Perhaps not definite proof, but certainly a test of an assumption.
https://en.wikipedia.org/wiki/Eratosthenes
This is not to disagree with the thrust of your argument, however :)
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.
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.
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.
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?
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).
No you can't, because it is logically impossible. If you can experience effects that it causes, it isn't a separate universe. To test it, you must observe effects caused by it's existence that would not be expected to be present if it did not exist. Ergo, you cannot test the existence of other universes.
> 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
Sure. But you can't ever observe that you have created it (or, more precisely, you can't ever observe anything that would distinguish what you have created as another universe, only as an object in our universe.)
Not that, even if it were possible to observe, creating universes in the lab would in any way test multiverse-based cosmological speculations.
2,200+ years ago, and while they couldn’t test it by going around it, still, they could test it with a prediction of measurement differences which would be found if it was round and would not be found if it was not, and, as a bonus, whose magnitude would also tell the size of the earth if it was round. Could—and did. The prediction was not untestable, even with the technology of 194 B.C.
> Actually, in many of his talks he [Arkani-Hamed] explains clearly the motivation for the hype: it’s to motivate himself.
She's also a talented singer and has some music videos on her channel as well.
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".
Also, what is wrong with people who question the politics and alarmism around climate change? Isn't the ability to question something fundamental to scientific reasoning? I don't think your dismisal of people as "deniers" is very reassuring of scientifc reasoning in that context, and this is because I don't see people there who are denying scientific facts, but rather questioning commonly held assumptions.
It's arguably a necessary 'smear' because we've seen the same pattern play out as happened in the case of tobacco: there's a lot of money at stake, and people and organisations with a lot to lose and a lot to spend are not above spreading FUD, laundered through any scientists or 'public intellectuals' who either already hold a conveniently contrary view or are willing to be convinced by $. We'd be naive and foolish to let this happen without pointing out the pattern and calling into question the reputations of the contrarians.
Not commenting on the rest because I don't know much about it, but saying that the quality of youtube comments under a video says something about the quality of the video is, I think, quite unreasonable.
Judge ideas for the ideas themselves, but this is a clear red flag and points to the type of community she is building.
She ended the video saying the opposite [0]. She said she personally does not doubt that the signals are caused by gravitational waves but points out that "in science evidence counts'. They, according to her, haven't conclusively eliminated other terrestrial sources that could cause the signals. [0] https://youtu.be/WWTvNlfkvoI?t=595
What specifically are you accusing Hossenfelder of lying about? I read your linked comment[0] and the Hossenfelder transcript[1], and your characterisation of a lot of the things she said doesn't match my reading of them. But even taking your reading as correct, I don't see where you've identified cases of Hossenfelder giving "information that [she knows] is false".
[0] https://news.ycombinator.com/item?id=21448974 [1] https://backreaction.blogspot.com/2019/11/have-we-really-mea...
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.
In her book "Lost in Math" a target of ire has also been supersymmetry, though she dislikes supersymmetry for another reason, namely the fact that it relies too much on justifications of "beauty" to survive all of its empirical short-comings. In her view, the fact that supersymmetry solves the hierarchy problem is more an aesthetic point (and therefore irrelevant), than a mathematical or logical necessity.
Anybody who says yes is selling something. "Maybe" is not necessarily dishonest.
edit: punctuation
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?
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?
The sequence of thoughts from the moment each clone realizes it woke up in room X, depends on the value of X, which potentially has lasting psychological effects that boost the divergence of the two clones. For example: imagine you've been told that cloning doesn't "split" you in two equally "genuine" clones, buy instead that the first one is the "original" whole the one in room 1 is the "clone". When you wake up and realize you are the clone, your thought process will probably diverge from the original.
As soon as the copy was created, it would diverge. But both would have ~equal claim on being "me".
> They'd have no way to tell which of the two entities they are though.
Not until they learned it from someone authoritative.
From your answer it seems you're also ruling out, a priori, the possibility that cloning a conscious being is not only impossible in reality, but absurd, regardless of any concession that would allow consciousness to still transcend matter (provided it allows for cloning).
I'd be interested to hear your thoughts on how you derive such strong conviction about the non-cloneability of conscious beings.
For example, in your scenario, neither of the consciousnesses is ever going to experience what the other experiences. Thus they must be different, and not truly clones.
On the other hand, if I copy a piece of software, it is in some sense the same software in both instances, though their histories are different.
Apparently we don't mean the same thing by "cloning". Let's call it "forking".
Btw, the same "uniqueness" issue applies to running software as well. The instance of a running software is not the same thing as the code of the software. If you take a snapshot of a software running on machine A and resume it on machine B, they no longer _are_ the same instance. It's clear that they exist independently because you can act on them independently and their state and future reactions will diverge.
That said, it's trivial for us to run n copies of the same state transitions with software (in lock step), something that might just not be possible for us to do with arbitrary precision on biological systems. That's not what I meant by cloning: I'm not saying having an exact "lock-step" reproduction of whatever the internal mechanism of consciousness is (that would be another debate).
But let's get back to the main point of my argument in this thread:
Wigner's friend thought experiment is absurd/paradoxical only if we cling to the notion that we'd somehow be subjectively affected by the fact that nature effectively forks off and entertain parallel histories for complex systems such as conscious beings in the same way as it seems to fork off and entertain parallel histories for simpler quantum systems when they are in superposition state. We don't have to invoke the many-worlds interpretation, which is just an interpretation; we can jus look at the math that describes how quantum states evolve: our most accurate description of what we observe in the world tells us that the behaviour of particles is consistent with viewing them as if they fork off and evolve in parallel over time until, at some point, when we add ourselves in the mix as "observers" then suddenly puff this superposition collapses and we observe the particle having a concrete state, at random.
Common ways to explain this collapse are:
1. The act of observing a system, done by a conscious being, collapses the quantum state, because consciousness is special
2. A conscious being it's just a very complex system that obeys the same rules governing the system it obseves, and thus gets involved in the superposition while performing the measurement, literally becoming part of the superposition. Thus the observed randomness is just an artefact of subjectively "waking up in room 1"
Wigner's setup exaggerates this problem by adding another observer (the scientist friend). It poses absolutely no problems of you espouse the second explaination above. It poses all sorts of problems if you absolutely cannot stomach the possibility that all of us people might not live in a uniform linear objective reality that works according to our intuition.
Simple != Intuitive
Of course, that's different from people being cloned all the time implicitly, aka many-worlds.
However, my instincts also tell me that reproducing quantum states for quantum computing must be basically the same thing as cloning objects, difficulty-wise, so I expect large quantum computers to become exponentially difficult to construct - but smart people who actually understand the math don't seem to believe that. So I don't have firm grounds for knowing the world works the way I think it does.
That doesn't require us to clone an object; the argument only requires us to imagine how would it feel if it's happening all the time to us and conclude that we wouldn't feel a thing subjectively.
Certainly Occam's Razor implies that we are.
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.
It doesn't seem startling or interesting that people continually find ways around rules that are not rules.
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.)