[HN Gopher] Confessions of a Theoretical Physicist
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Confessions of a Theoretical Physicist
Author : signa11
Score : 151 points
Date : 2024-08-23 05:14 UTC (17 hours ago)
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| nyc111 wrote:
| "Yet these are concepts that reify a certain approximate sketch
| of the structure of the world. Physicists once thought that these
| categories were fundamental and real, but we now understand them
| as necessarily inexact because they ignore the finer details that
| our instruments have just not been able to measure."
| FeepingCreature wrote:
| Sure, quarks and leptons are maybe a high-level concept that
| masks a more messy underlying reality, but surely quarks and
| leptons are _less_ messy than dogs? There is an arrow of progress
| in the development of physical theories. I don 't see a reason
| why a perfect description should not be possible.
| infogulch wrote:
| Even wrong theories can be useful in some contexts, Newtonian
| gravity for example. Take it to an extreme: say quarks aren't
| useful at all for science, but are a useful conceptualization
| pedagogically, it can still be worth.
| danbruc wrote:
| _Even wrong theories can be useful in some contexts,
| Newtonian gravity for example._
|
| Newtonian gravity is not wrong, it is pretty good model of
| gravity in a certain region of the parameter space.
| moi2388 wrote:
| Right. Well, by the same logic my theory of gravity isn't
| wrong: everything falls at 9m/s.
|
| It's not wrong, it's just a pretty good model of gravity in
| a certain region of the parameter space.
|
| Except of course, that it is wrong.
| danbruc wrote:
| Everything falling at a constant speed of 9 m/s takes
| this probably a bit too far, on Earth this will only be
| true for tens of milliseconds before the speed is of by a
| few percent. Had you said every objects accelerates with
| 9.81 m/s2, that would be a pretty good theory of gravity
| on the surface of Earth, probably still the dominant
| theory for solving gravity related problems on Earth.
|
| Your example reminds me more of the difference between
| Aristotelian and Newtonian physics. Aristotle - looking
| at the world around him - thought that the natural state
| of motion is being at rest and that it requires a force
| to make an object move. Newtonian physics realizes that
| this is not the case, that without forces objects keep
| moving instead of coming to rest, that Aristotle lacked a
| proper understanding of the role of friction.
|
| To come back to gravity, space flight probably still
| heavily uses Newtonian gravity and it works, for that
| reason alone I would not call it wrong. Objects falling
| at a constant 9 m/s seems to have much less practical use
| and does not even get the most important characteristic
| of gravity - that it accelerates objects - right, so I
| will agree with you and call it wrong.
| FeepingCreature wrote:
| The difference is that the region your theory of gravity
| is a good model in, is not inhabited, whereas the region
| that Newtonian gravity is a good model in is the one
| where most of us spend most of our time.
| tines wrote:
| It seems that different people often use "not wrong" to
| mean two different things. Some people are using the word
| to mean "useful as far as it's meant to be," like you. Some
| people, like the GP, are using it to mean "the truth." It's
| important to clarify what you mean when you're discussing,
| otherwise there's heat and not much light.
| danbruc wrote:
| In case of physics we do not really have access to the
| later kind, every theory is a current best guess that
| might at any time turn out to be only approximately
| correct or under certain circumstances. General
| relativity is almost certainly not the truth, the
| universe probably has no singularities hiding behind
| event horizons, but does it help us to call it wrong?
|
| There is reality and there is series of better and better
| mathematical models of reality and all of them are wrong
| in the strict sense until we eventually find the final
| theory but even then it is not clear that we could even
| recognize that we have arrived at the destination. In the
| end a binary characterization as right or wrong does not
| make too much sense for physical theories, they occupy a
| continuum of correctness.
| tines wrote:
| I somewhat agree with you, but I think it's very
| important to distinguish between the two meanings,
| because different points on the continuum of correctness
| cause you to come to completely opposite conclusions
| about the nature of the universe. A bit of quantity leads
| to a totally different quality. In other words, truth and
| usefulness are continua, but they are _two different and
| orthogonal_ continua, and going right on one may mean
| going left on the other.
|
| My view of the universe is going to be totally different
| if Newtonian mechanics is the "truth", versus if
| something like quantum mechanics is the "truth." The
| former depicts a totally deterministic and knowable-in-
| principle clockwork universe, whereas the latter has
| randomness and ignorance that cannot be removed even in
| principle. Quantum mechanics may not be the whole truth,
| but it's certainly so different that it shows earlier
| approaches to be not just incomplete but totally
| incorrect about their fundamental assumptions, even if
| they can be used to make useful predictions. Quantum
| mechanics isn't just more useful, it's more true, whereas
| Newtonian mechanics might be more useful than some other
| theory, but actually less true in some sense.
| nathan_compton wrote:
| Counterpoint: Newtonian Gravity could be considered
| _profoundly_ wrong since it presupposes a structure for
| space and time which is fundamentally wrong. What I mean is
| that ontologically Newtonian Gravity is a total non-
| starter, implying the existence of relations which are
| simply totally absent in this universe.
| CoastalCoder wrote:
| > but surely quarks and leptons are less messy than dogs?
|
| I dunno, I'd rather clean up an accident from a dog than from a
| particle accelerator.
| lokimedes wrote:
| Physics is an empirical inquiry into the structure, composition
| and dynamics of the observable usensorium we inhabit. I find it
| just short of hybris to entertain any promise that the outcome
| can be more than a metaphor of the underlying reality. The whole
| quagmire of "the measurement problem" in quantum mechanics seems
| to largely come from misunderstanding Bohr's philosophical
| objections on this difference between a theory of the measurable
| and the interpretation of the theory's internal mechanics as
| evidence of the true reality it models.
|
| Givens that twentieth century physics (apart from General
| Relativity) is based on Bohr's foundation, no wonder people get
| confused.
|
| The mathematization of physics hasn't helped either. That Bell's
| theorem "proves" something is language applicable to a
| mathematical structure, not to the physical world itself.
| elashri wrote:
| Why can't you just shut up and calculate? /s
| lokimedes wrote:
| Exactly
| DiscourseFan wrote:
| formulas are meaningless without concepts
| gpderetta wrote:
| c.f. "The unreasonable effectiveness of mathematics in the
| natural sciences"
| (https://www.maths.ed.ac.uk/~v1ranick/papers/wigner.pdf)
| DiscourseFan wrote:
| > It is even possible that some of the laws of nature will be
| in conflict with each other in their implications, but each
| convincing enough in its own domain so that we may not be
| willing to abandon any of them. We may resign ourselves to
| such a state of affairs or our interest in clearing up the
| conflict between the various theories may fade out. We may
| lose interest in the "ultimate truth," that is, in a picture
| which is a consistent fusion into a single unit of the little
| pictures, formed on the various aspects of nature.
|
| Mathematics _alone_ cannot reflect on its conditions of
| possibility, and mathematical physics is as inept in that
| domain. The reason why the quantum physics vs. general
| relativity thing can 't be resolved is not because we don't
| have the right math, its because to overcome it requires a
| paradigm shift _away from_ the mathematization of physics,
| and to actually gain a familiarity with the conceptual
| apparatus that engendered these theories.
| ko27 wrote:
| It's funny that you mention hubris and yet you fall victim to
| it by dismissing the measurement problem and Bell's theorem.
| It's true that our theories are not a perfect description of
| "true reality", but they do tell you something about what "true
| reality" must be.
|
| > That Bell's theorem "proves" something is language applicable
| to a mathematical structure, not to the physical world itself.
|
| This is simply wrong, Bell's theorem definitely applies to the
| "physical world". A world that does not violate Bell's
| inequality would look vastly different to ours.
| simonh wrote:
| >That Bell's theorem "proves" something is language applicable
| to a mathematical structure, not to the physical world itself.
|
| Do you not accept the validity of experimental verification?
| sanxiyn wrote:
| I mean, leptons are definitely real, not just concepts. An
| electron is a lepton, and an electron surely exists? You can
| spray individual electrons. If an electron is just a concept, it
| is in a sense that a tiger is just a concept, and in a sense it
| is, but that is not very useful thing to say.
| anatoly wrote:
| An electron is just an excitation of the electron field, a vast
| probabilistic something that's ever-present everywhere in the
| universe, with a different complex-number amplitude (not
| observable directly) at each and every point. Sometimes that
| vagaries of its ever-changing amplitudes cause it to locally
| coalesce into something that looks like an individual electron
| if you squint at it in the right manner, and that vision
| persists until a strong enough interaction with another vast
| and nebulous field shatters the illusion, at least in the tiny
| corner of the probabilistic multiverse your local version of
| your consciousness brazenly imagines to be the objective
| reality. What kind of existence is that?
|
| (Well, the only kind on offer, really.)
| goatlover wrote:
| An existence that mistakenly took fundamental reality to
| consist of point particles instead of fields. But we still
| found out about fields and quantum mechanics.
| dist-epoch wrote:
| We don't know that fields are real. We just know that the
| mathematical language of fields is the most convenient and
| concise to describe the experimental results we see.
| goatlover wrote:
| As a starting pint, the magnetic field can be shown to be
| real with metal filings. Whether fields are the
| fundamental building block is another matter.
| digging wrote:
| > I mean, leptons are definitely real, not just concepts.
|
| Have you informed Dr Balasubramanian?
| BrandoElFollito wrote:
| I am an ex-physist who stopped after his PhD in particle physics.
| I love physics but while money does not bring happiness, it is
| better to cry in a Mercedes than on a bike (this is not true, I
| just laughed when I first read it).
|
| I went through the stages of OP (on a way smaller scale, I do not
| have his experience) and I think this is awesome. You
| continuously go from "oh yeah, now I get it" to "crap". This
| always have you on the bleeding edge between "this si physics, I
| know that" and "yes, but what if...". To me this is the essence
| of knowledge though curiosity.
|
| I started my PhD on a specific topic and at some point I was a
| bit stuck (not panic mode stuck but pissed off stuck). I had
| dinner with a friend, we were discussing about my work (she is
| also a physicist) and she off-handly suggested something. And
| bam! my world changed. The direction of the thesis changed. I
| added an extra thesis director because what I was about to do was
| a world where the hands of men did not step on yet.
|
| I thanked her profusely for her help in the thesis and suggested
| a joined publication (which she did not want to take because she
| was not interested and asked me to stop stalking her :))
|
| And this is how science moves: because of eureka moments under
| the shower or at dinner or because someone thought "hmmm..."
| (looking at you Nikola Tesla).
|
| So the fact that this guy doubts about what the world is, and
| that he is a theoretical physicist (so hopefully will not switch
| to some insanities) is awesome.
| kaiwen1 wrote:
| Off topic, but eureka moments are my favorite go-to evidence
| for the absence of free will. No one chooses to have a eureka
| moment. They just arrive. And not just those moments, but every
| thought in every moment. They all just arrive, none are
| choosen.
| futuramaconarma wrote:
| That's not evidence But I agree there's no free will and
| anybody who believes it also believes in magic and god
| mettamage wrote:
| I experience having mo free will whenever I am in the break
| of a meditation retreat. During those breaks it's sometimes
| quite easy to observe my thoughts, given that I focus 10
| hours per day on making my internal chatter very very
| quiet.
|
| The most fascinating thing to me is how subtle body
| sensations lead to thoughts and vice versa.
| mensetmanusman wrote:
| People who disbelieve in free will are often not educated
| in the fact that the laws of physics don't include
| explanation of most of what is observed and clearly lack in
| the area of the existence of mind, and are therefore
| extremely incomplete.
|
| Also, it's impossible to disprove the existence of free
| will because it requires will to make a conclusion like
| that.
| Vecr wrote:
| Why? A robot should be able to disprove free will by
| following the rules of correct reasoning, if such a thing
| is relatively easy, i.e. you would expect humans to ever
| solve it.
| Workaccount2 wrote:
| This is just a free will version of "god-of-the-gaps",
| where you can shovel the basis of any unknown into the
| gaps of scientific understanding. We know far more about
| physics and the mind than we did 100 years ago, and the
| boundaries for free will to exist in have done nothing
| but shrink. Not even leaving a mark or hint behind.
|
| Free will is much closer to leprechauns (we still haven't
| mapped every forest!) on the truth spectrum than it is to
| cancer cures or fusion energy.
| mensetmanusman wrote:
| I would believe you, but you had no choice but to output
| that information, so it's noise :)
| NemoNobody wrote:
| You haven't thought about this enough. Make it small so
| it's understandable - say any game involving choice. One
| has free will within the predetermined set of conditions
| of the game. A choice to buy a property or not in
| Monopoly seems like free will but it isn't really. Life
| is the same.
|
| Considering that we as human beings don't get to decide
| what exactly we remember, recall, when we recall or how
| much we recall - that is memory. What we remember and
| what we forget. I point this out because it's not a
| conscious activity but also determines actions, greatly
| so even.
|
| In the Monopoly example perhaps a property is bought bc
| its a favorite color or they remember winning before with
| it or its the one they kno their cousin wants. Whatever
| the personal reasons, there are reasons - nobody plays
| Monopoly with all logic and reason.
|
| So we have limited circumstantial choices and
| predetermined biased assessments of those choices - both
| beyond our control.
|
| What is free will in that context?
| mensetmanusman wrote:
| Complexity is unbounded, so the discussion around free
| will probably makes more sense on the opposite end of the
| choice spectrum. We have a countably infinite number of
| choices (due to thermodynamic energy limits) to make even
| within a framework of quantum mechanics, where electrons
| can only have discrete energy levels (limited number of
| 'choices'). Choosing meaning from the infinite looks more
| like free will than deciding heads or tails.
| istultus wrote:
| Beyond that logical tantrum easily refuted - I'm 52% on
| free will, say a tenth of a bip on god and magic:
|
| At least in Judaism there is sizable chunk of believers who
| believe in God and that everything is God's will and thus
| there is no free will - Hashgachah Pratit - so at the very
| least only one direction of your argument could hold,
| though I don't understand why it's a coherent idea to begin
| with.
|
| (also, which particular audience are you trying to insult
| with that categorical statement and why?)
| dsizzle wrote:
| You should read about compatibilism, e.g. the work of
| Daniel Dennett, which argues that the parts of free will
| worth wanting are consistent with determinism. He
| definitely doesn't believe in magic or god!
| mensetmanusman wrote:
| Because instincts exist, there is no free will.
|
| (Although free will is required to make any conclusion about
| the presence or absence of free will, so the point is moot).
| thrance wrote:
| Grandparent's argument is ridiculous but so is yours, how
| is free will required to make a conclusion on the existence
| of free will ?
| mensetmanusman wrote:
| Making any conclusion requires the use of a will,
| otherwise it's just a coin flip, and random decision
| aren't part of logical frameworks.
| Vecr wrote:
| Yes they are, look at the derandomization program in
| computational complexity, or if you're slightly more
| forgiving with your definition of logic, then look at
| mixed strategies and Monte-Carlo algorithms.
| mensetmanusman wrote:
| *only random decisions can't come to a conclusion. That
| would mean a random proof of free will is just as valid
| :)
|
| Definitely random generators can be a subset of logic,
| not the superset.
| Vecr wrote:
| I don't know what you're saying. A derandomized Las Vegas
| algorithm is deterministic for a given seed, so far so
| good. From there I'm lost.
| InDubioProRubio wrote:
| Eureka moments, is the subconscious assembling conclusions
| and deductions and presenting them to you. That the
| subconscious is engaged and busy, is fed with information to
| build stuff from and rewarded for its actions - thus repeats
| it, is all conscious choices, thus subject to free will. The
| horse does pull of a record and the rider barely had to
| steer, is not a indicator of wild horses.
| pwm wrote:
| One thing I've discovered and utilised from a relatively
| early age was synergising the difference in how my
| conscious and subconscious processes information. It's
| really just the usual advice of "when stuck, go for a walk"
| but in my experience it's a very useful tool when done
| mindfully.
| cameldrv wrote:
| I don't think it rules out free will, but perhaps free will
| is more limited. There is a self reflective part of your
| mind, probably physically located in your frontal lobe, but
| there are also many other parts of your mind and brain that
| do important things, but aren't self reflective. I've come to
| think of my brain as a committee. There are many things I can
| do, like walk or even do a mathematical proof, that I cannot
| really describe the process. We see in things like addiction
| that the self reflective mind also does not always (or maybe
| even often) have ultimate control over behavior. Kahenaman
| and Gallwey talk about this as System 1/2 and Self 1/2.
| Julian Jaynes even thinks that people used to have complete
| other simulated people inside of themselves that they called
| gods, and this still happens to people with Schizophrenia.
| sgt101 wrote:
| I choose thoughts - I can conjour images, or scenes into my
| mind. I can choose not to think about things.
|
| In fact, this is a proof of free will. If you were compelled
| to consider the consequences of your actions then evil would
| be impossible. The fact that we see evil means that people
| can choose not to think about what will happen when they do
| evil things.
| lostmsu wrote:
| Not really, the decision to choose a particular thought
| first comes into your mind the way above comment says.
| sgt101 wrote:
| Really - to state otherwise is just a play on words.
|
| Think carefully. Think friend, think.
| tasty_freeze wrote:
| As the famous quote goes, you are free to choose, but you
| aren't free to choose what you choose.
|
| Unpacking: assuming you aren't coerced, you choose one of N
| options "freely". But all the factors (many inscrutable)
| that contribute to the ultimate choice are predetermined
| from your biology to all your lived experience (which
| ultimately is encoded in your brain in some manner).
|
| Sam Harris has a short (7 minute) video with a
| demonstration of this. The demonstration starts about 1:20
| in, but it is worth watching the minute setup.
|
| https://www.youtube.com/watch?v=GXTEmu-jUqA
| dwaltrip wrote:
| I think, at this point, if someone says free will exists,
| beyond mere compatibilism, it should be required that they
| very carefully specify what the hell they are talking
| about.
|
| P.s. Am I wrong for assuming that whenever someone talks
| about free will without mentioning compatiblism, they most
| likely talking about some other form?
| ck2 wrote:
| You can still have free will with "locked in" events.
|
| Time is a fourth dimension but think of everything that has
| and everything that will happen as a three dimensional cube
| for a moment.
|
| Now step outside the cube and observe everything that has and
| ever will happen.
|
| Does that mean there was no free will because it's all
| observable and was "locked in" ?
|
| No of course not. It's a unique box of time. If you look
| around there could be another unique box of time with
| different free will choices being made inside it.
|
| (btw this is one way they attempt to theorize an excuse for
| quantum entanglement, it "knows" the outcome already by also
| existing outside the box)
| api wrote:
| The choice is upstream. You choose what to focus on, which
| gives standing orders to your brain, which eventually leads
| to eureka moments.
|
| If you choose to focus entirely on baking you'll have eureka
| moments about that.
| dsizzle wrote:
| Why would you assume it's all or nothing? Will (free or
| otherwise) implies something like effort and clearly we're
| not constantly applying effort. Believing in free will
| doesn't mean believing that everything results from it.
| jll29 wrote:
| This is a bit like saying program counters don't exist
| because a program's control flow can be changed by
| interrupts.
| d0mine wrote:
| The presence of subconscious processes doesn't deny the
| existence of conscious ones.
|
| Focus/diffuses modes are widely known/accepted.
|
| You can direct the unconscious thoughts too. If I spend some
| time intensely trying to solve a problem on the conscious
| level, often I get new ideas on how to approach it in the
| morning or during a long run (without thinking about it on
| the conscious level).
|
| ---
|
| Unrelated: the discussions about free will often miss that
| the existence of atoms doesn't imply that a wooden table
| doesn't exist: they are on different levels of abstraction--
| no point in comparing.
| lukan wrote:
| One can want to have eureka moments.
|
| And than one thinks hard.
|
| And then one fine day "eureka!"
|
| But they do not happen on their own. It takes effort to make
| them possible, even though there is no guaruantee that they
| will come (Dead ends exists).
| thewanderer1983 wrote:
| It's refreshing to me to read articles like this. In the current
| climate of consensus science, and settled science. Here is
| someone well versed in Physics, and the Philosophy of it.
| Reminding people that we need to be humbled again.
| openrisk wrote:
| Do we care about "real" reality if we can, more or less, make
| sense of some of its manifestations through our senses?
|
| That there is something deeper and unknowable and
| "informationally huge" seems obvious. We didn't bring quarks or
| quasars into existence, we "discovered" them as and when we
| extended our senses far enough using technologies (which are
| themselves a result of us becoming comfortable enough with our
| immediate reality, as a sort of positive feedback loop).
|
| There is every reason to suspect that this deeper reality does
| not stop where our technologically extended abilities peter out.
| Our imperfect and tentative understanding when reaching the
| extremes of scales (of time, space, complexity, etc) is perfectly
| understandable. Why should a finite carbon brain be able to map
| out a coherent and finite model of something much, much bigger
| than itself.
|
| On the other hand over millennia of brainstorming (literally) we
| have collected some interesting datapoints about this deeper
| reality: it is not "malicious", and somehow it agrees to be
| mapped by us (mathematically), even if in disconnected parts.
|
| In fact this benevolent aspect of deeper reality has made us
| unusually cocky. Imagine the existential angst if the universe
| changed its laws at whim. We'd be back to praying. E.g., that
| gravity remains stable for a while so that we don't drift into
| space. This premature self-assuredness explains repeated
| scientific episodes of proclaiming "we have explained
| everything". This also feeds the sterile chase of "a theory of
| everything".
|
| In fact the limits of our understanding are in front of our eyes,
| everywhere. We haven't really explained a single phenomenon in
| the so called "complexity science" domain. Deeper reality is all
| around us and the most dramatic and impactful scientific
| revolutions are still ahead of us.
| DiscourseFan wrote:
| >Deeper reality is all around us and the most dramatic and
| impactful scientific revolutions are still ahead of us.
|
| Maybe
| graycat wrote:
| > Why should a finite carbon brain be able to map out a
| coherent and finite model of something much, much bigger than
| itself.
|
| Have asked that and have a guess: Darwin-style selection
| rewarded getting some rational understanding of the most
| important parts of nature -- fire, rock tools, clean water,
| agriculture, staying warm in winter, basic geometry, bows and
| arrows, the Pythagorean theorem, levers, wheels, boats, etc. --
| we encountered. Well, it so happens that in this universe such
| "rational understanding" is enough to understand basic math,
| physics, chemistry, biology, ... back to the Big Bang, the 3 K
| background radiation, cells, reproduction, nutrition, diseases
| and immunity, ....
|
| I gave up on the US education physics community when my
| teachers couldn't give a valid proof of Stokes' theorem,
| explanation of Young's double slit, or the beginnings of
| quantum mechanics.
|
| So, now I have several polished treatments of each of Stokes'
| theorem, Maxwell's equations, and special relativity. Got a
| good background in probability (Neveu, Poincare recurrence,
| martingales, etc.), enough to get a good path through
| thermodynamics. From Rudin, etc., got enough solid Fourier
| theory to check carefully the uncertainty principle in physics
| (doubt that what physics does there is fully justified) -- also
| carefully treated in a great course in "Analysis and
| Probability". For differential geometry, an Andrew Gleason
| student gave me some lectures and explained that the keys are
| the inverse and implicit function theorems, proved in a book by
| W. Fleming and just exercises in a Rudin book -- local
| nonlinear versions of what is easy in linear algebra. So, now I
| attack physics as a curious amateur!
|
| I do remember a remark from a good mathematician: "Physics
| abuses its students." Well, they can abuse me no longer, and I
| can still do high quality study of physics.
| slkjdlskjdklsd wrote:
| > Do we care about "real" reality if we can, more or less, make
| sense of some of its manifestations through our senses?
|
| we can - Who is the we?
|
| our senses - Whose senses? What experience the sensory input?
| catanama wrote:
| What's your answer to that?
| slkjdlskjdklsd wrote:
| I had an experience where I knew(not believe) I was the
| kind of the screen in which everything appears(including
| the human body). Lasted for a couple of hours.
|
| After the experience all the religious teaching started to
| make sense instantly.
|
| I think the thing is Self, Soul, Consciousness, Atman,
| Reality, Simulation, Screen or whatever you call it.
|
| It's what all the world religions point to.
|
| Though teachings has been made so hard to grasp by culture
| and dogma.
|
| It's something you(the ego) cannot know without
| experiencing it. You can try to believe it. But the ego
| will not let you.
| catanama wrote:
| That's interesting. What's your take on what ego is and
| why it won't let you experience it and what to do about
| it?
| slkjdlskjdklsd wrote:
| I don't think the ego has any intent. I think it's a
| collection of memories and emotions that you have
| accumulated over the past. Like a cache that is outdated.
|
| Imagine your knowingness as an information stream of
| images (memories included), smell, feelings, sound etc.
|
| For most people the information stream has the ego
| dominating.
|
| When the ego is strong people identify themselves with
| the idea of them based on their memories, beliefs,
| culture etc.
|
| When the ego goes away I think you are left with who you
| really are which when you experience feels eternal and
| permanent and is a placeholder in which everything
| appears.
| catanama wrote:
| Any idea why we don't have a button to stop this
| simulation scenario and return to that "who you really
| are" mode?
| slkjdlskjdklsd wrote:
| The button is historically called as enlightenment,
| moksha, liberation etc. But it's hard to attain.
|
| Maybe it likes all the drama and want it to forget who
| really it is? Like how we play games or watch movies?
|
| Or maybe the forgetfulness is a side effect of creation
| and not intended.
|
| Maybe it has no intent.
|
| I am not sure. I can only guess as an ego by referring to
| things I saw in the past.
| catanama wrote:
| Did you find anything specific which can help you to get
| back to free state?
| swayvil wrote:
| A river of sensations. A play of attention. That's reality. The
| rest is fiction.
| slkjdlskjdklsd wrote:
| I don't think the ego accepts this easily.
| catanama wrote:
| >We didn't bring quarks or quasars into existence, we
| "discovered" them as and when we extended our senses far enough
| using technologies
|
| Did we? If we're in a simulation instead of base reality, it's
| possible that simulation have actually created them for us when
| we started looking, depending on the scope and paramaters of
| simulaiton scenario.
| rralian wrote:
| Not sure why this is getting downvoted. The idea that the act
| of observation impacts an experiment (or how particles
| behave) is one of the most counterintuitive and surprising
| "truths" I've ever heard. I would love to hear a logical
| explanation of why (not just a description of it).
| 082349872349872 wrote:
| The logical explanation: "observation" has nothing to do
| with conscious woo, it's just that _in order to have a
| definite answer_ we build experiments so they collapse the
| wavefunction.
|
| It's like asking someone on a date: maybe they were in a
| superposition before, but now they have to answer, and
| having answered ("been observed"), that answer is highly
| likely to stay constant in the short term.
|
| (when you think about it from this point of view, it's
| classical physics that's counterintuitive: why should we
| expect that asking questions about one projection of state
| doesn't affect the answers we get from later asking about
| others, not even in the slightest?)
|
| Does that make sense?
| catanama wrote:
| The point I was trying to make is that if we are indeed
| in a simulation, and I'm not saying that we definitely
| are, but if we are - one possibility to design such a
| simulation in a way to make it more efficient is to
| actually make computations depend on the observer,
| meaning that sorry, but in this case it would have
| conscious "woo" built in.
|
| Just in the same way as that only visible from current
| perspective objects are being drawn on a frame of a 3D
| game.
|
| Currently unobserved parts of the simulation might exist
| in different form.
|
| It's okay to disagree with simulation theory, but it is a
| perfectly valid possibility according to everything we
| know.
|
| Personally, I don't think it's the only possibility, but
| i think it's quite probable and should be taken
| seriously.
| 082349872349872 wrote:
| The reason for my personal choice to not take simulation
| theory seriously is because simulations are an instance
| of Russell's Teapot. Anything which can be explained as S
| simulating T can be explained more simply as just T (or,
| in the opposite direction, even more complicatedly as R
| simulating S simulating T, etc. Can* we go all the way to
| a countably infinite tower of simulations?).
|
| * if yes, then I'd have to admit that the omega-tower
| could be as interesting to study as the 0-tower, but if
| no then I'd maintain the 0-tower is way more interesting
| than any of its successor towers.
| nathan_compton wrote:
| One problem is that gravity is universally coupling, so
| no part of the universe is technically "unobserved." I
| suspect that we could look back at the dynamics of large
| scale systems and see deviations from GR if the
| simulation were neglecting any part of the universe in
| the absence of observation/interaction.
|
| If I were building a simulation I would just have not
| made gravity universally coupling because it makes it
| hard to chunk reality up into parts. Thus it seems like
| the universal coupling of gravity is evidence against a
| simulation hypothesis.
| nonameiguess wrote:
| If we were in a simulation, due to the hard problem, it
| would be impossible for the simulators to know whether
| anything in their simulation had qualitative experiences,
| so they could not make conscious observation a
| prerequisite of detail rendering, only interaction. No
| woo necessary.
| goatlover wrote:
| Decoherence from the measuring device is why the wave
| function appears collapsed.
| nathan_compton wrote:
| Observation doesn't impact experiments. Interaction does.
| In fact, it is quite difficult to formulate the "collapse"
| of the wavefunction as a physical interaction and to the
| extent that we can, the experimental evidence seems to
| suggest that it is not. This is a common misconception
| about quantum mechanics, partly because even undergraduate
| texts conflate the uncertainty principal with observation.
| alexpc201 wrote:
| It reminds me of the plot of the novel "The Three-Body
| Problem."
| _hark wrote:
| I'm in the final year of my PhD, and I feel very lucky to be
| working on the question of what it means for an explanation to be
| "good". The closest thing to a satisfactory resolution of the
| question of "reality" in theories, to me, is Dennet's _Real
| Patterns_ [1]
|
| It may well be that multiple explanations are consistent with the
| most basic phenomena. The criterion for the reality of the theory
| is whether it does better than random (its predictive power,
| equivalently how well it can compress the observational data). We
| can try to find the simplest explanation, but we can never know
| if we have it [2]. We can stop thinking of theories as being real
| or not in a binary sense, and merely ask how well they compress
| the data. Of course, different theories can achieve the same
| compression by compressing different aspects of the data! Your
| pattern can look like my noise :-)
|
| Luckily and interestingly, the physics of the macroscopic world
| is in many cases effectively independent of the underlying
| microscopic rules [3], with the details of the microscopic
| physics being screened off as complexity emerges.
|
| Personally, I like to think of abstraction as a kind of hierarchy
| of hardware + software: at each level, some useful ontology is
| picked out for stable patterns to emerge (e.g. the software of
| "fluids" emerging from the hardware of quantum "particles").
| Layers of software at one level become the hardware substrate for
| the next rung up the abstraction ladder.
|
| Luckily, we get to choose the software that runs on us, so don't
| forget to vote this fall ;)
|
| [1]: https://ruccs.rutgers.edu/images/personal-zenon-
| pylyshyn/cla...
|
| [2]: https://en.wikipedia.org/wiki/Kolmogorov_complexity
|
| [3]: https://en.wikipedia.org/wiki/Effective_field_theory
| jll29 wrote:
| > what it means for an explanation to be "good"
|
| Chomsky coined the technical term "explanatory adequacy" for
| that, which is used/recognized among linguists and
| psychologists.
| dakiol wrote:
| I didn't know that Physics was about understanding reality (sure,
| from a romantic perspective yeah). I always thought it was about
| making our lives better (like any other branch of science).
|
| I believe we will never find out what's the real nature of
| reality. That doesn't mean we should stop doing science, though:
| it makes human live better.
|
| I believe that the "meaning of life" is not about the answer
| (science telling us what's the actual meaning) but about the
| discovery process we embrace: knowing beforehand that we'll never
| understand everything and nevertheless keep waking up every day
| to do the job.
| jajko wrote:
| Understanding reality makes our lives significantly better. No
| room for primitive religions leading us to stagnation or even
| reversal, when we can understand very well what sun, moon and
| stars are, why they move as they do, or why lightning happens
| and why weather patterns are what they are.
|
| Understanding of reality via physics gave us all electronics
| too, including one I use to write this and one you use to read
| it. That's a noble goal on its own, no need to meddle with
| that.
|
| Pursuit of meaning of life is completely different topic, for
| different folks, no need to try to mix those two. Plus its very
| subjective - tons of folks already found it or simply don't
| care about it.
| hnfong wrote:
| > Understanding reality makes our lives significantly better.
|
| Of course _on the whole_ understanding makes our lives
| better, but if you 're asserting this for everything, it's
| probably some kind of a survival bias. The understandings
| that aren't really useful are often forgotten, while the
| useful ones are passed down through generations.
|
| It's actually very easy to get caught in understanding niche
| topics that genuinely find very little application.
| mistermann wrote:
| Is all potentiality that exists unlocked and harvested? Is
| science even looking in all the right places? Can a mind on
| science even care about such things (or better: _to what
| degree_ do individual and a culture /society of minds on
| science have the ability to care (have non-constrained
| curiosity))?
|
| In my experience, something about the mind makes it think
| it is able to know the correct answer to these questions,
| which is a remarkable but little studied phenomenon.
| mistermann wrote:
| > No room for primitive religions leading us to stagnation or
| even reversal, when we can understand very well what sun,
| moon and stars are, why they move as they do, or why
| lightning happens and why weather patterns are what they are.
|
| Do you mean this literally, as in this is _knowledge_ (JTB)
| that you possess?
|
| > Pursuit of meaning of life is completely different topic
|
| Is this a part of reality, or of something else?
|
| > no need to try to mix those two
|
| How does one go about accurately determining what is
| _needed_?
| slkjdlskjdklsd wrote:
| > . I always thought it was about making our lives better
|
| That's Engineering not Physics.
| bjornsing wrote:
| I could have been a theoretical physicist, but got out after my
| master's. Subconsciously I think I had already come to this (the
| OP's) conclusion then.
|
| Since then I've worked a bit in statistics and machine learning.
| There's a saying in this field that captures my subconscious
| conclusion well: "all models are wrong, but some models are
| useful".
|
| I've often said that I would have loved to do a PhD in physics in
| 1910, but less so in 2010. The models physicists found in the
| 20th century were extraordinarily useful. I have little hope that
| I will see anything comparable in my lifetime.
|
| Don't get me wrong: More models will undoubtedly be found, and
| there's beauty and honor in that work. But they will most likely
| all be "wrong", and far less useful than e.g. the models that let
| us harness nuclear reactions.
| sigmoid10 wrote:
| That depends a bit on the field. If you were doing particle
| physics (in particular using earth-borne accelerators), the
| second half of the 20th century would probably be best. But if
| you're into astroparticle or cosmology, the best time is
| literally right now. The 21st century has been one giant thing
| after another thanks to Sudbury, WMAP and Planck, the EHT,
| LIGO, the Pulsar Timing Array and tons of other experiments.
| When it comes to understanding the universe as a whole, there
| is no better time to work in physics than today. Similar goes
| for quantum and condensed matter, albeit with a focus on real
| world applications rather than understanding the universe.
| bjornsing wrote:
| I'm into usefulness. And I'm not convinced by your argument.
| I still doubt very much that I will see any new models as
| useful as those that transformed the world in the 20th
| century. I'd love to be wrong though.
| momoschili wrote:
| This is bit of a commonly misheld perception in my opinion.
|
| It took 30-50 years for anything in the 1910s to become
| particularly useful. Even the photoelectric effect itself took
| over 30 years before the first devices (photomultipliers) were
| even developed.
|
| The much celebrated quantum mechanics likely wasn't so useful
| either until 30-40 years later with electronics such as
| transistors.
|
| General relativity didn't really find a use until GPS and that
| was over 70 years later.
|
| The only field that contributed 'relatively' quickly during
| that time period was nuclear physics, but that field saw an
| extreme concentration of effort due to the war.
|
| Meanwhile theoretical condensed matter physics today is rife
| with things that are on the cusp of being useful with 2D
| materials, superconductors, quantum simulators, etc
| swayvil wrote:
| We do not craft models of reality because reality and models have
| any kind of intrinsic connection. We craft models of reality
| because we value models.
|
| That is arguably very funny.
| TheOtherHobbes wrote:
| So this is the new zeitgeist. Between AI, quantum fundamentals,
| disinformation, and a few other less obvious trends, "reality" is
| going to get less and less concrete and more and more contextual
| and non-binary.
| jeroenvlek wrote:
| Ultimately, we're all just living in an episode on Rick & Morty's
| galactic cable TV
| efitz wrote:
| Humans are not "generally intelligent"; our intelligence is
| extremely well adapted to being a hominid family animal in a
| tribe or clan in a savannah habitat with large predators and
| hostile members of our own species lurking about.
|
| Our senses and brains are well suited to reasoning about and
| making decisions in environments at "human" scales. By that, I
| mean that humans don't receive relativistic, atomic or quantum
| phenomena directly with our unaided senses, and therefore our
| brains never developed intuition for these phenomena.
|
| So it's no surprise at all that our intuition completely fails us
| at those scales.
|
| Again, our intelligence is not "general"; it's hominid.
| snovv_crash wrote:
| We also fail horrifically at recognising exponential growth, or
| understanding its implications.
| mettamage wrote:
| Exponential growth is pretty rare in nature, right?
|
| Linear growth or fuzzy up and down growth/swings seems way
| more commonplace
| LgWoodenBadger wrote:
| and yet plenty of us can expertly catch balls thrown in the
| air
| Vecr wrote:
| By more or less holding its angle constant by moving. The
| intercept trajectory is nowhere near optimal.
| robwwilliams wrote:
| I love this comment! Why have I never read this key insight in
| the form of an essay. Having recently watch Chimp Empire on
| Netflix I have a good feel for the "lower" foundational levels
| of our stack.
| 11101010001100 wrote:
| We complement this weakness with tools. Now can we build tools
| that access all mass-energy scales is the question...(or do we
| need too :P)....
| olooney wrote:
| And yet, counterintuitively, it's in precisely these areas
| (relativity, quantum physics) that our theories are best (most
| predictive with the strongest mathematical foundations) and the
| areas where our human intuition ought to supply the most
| assistance (psychology, sociology) where we seem to be lost at
| sea.
|
| One explanation that I've come up with to explain this apparent
| paradox is that while humans may not have any special insight
| or intuition into microscopic or macroscopic phenomenon, at
| least we don't have any biases either. Thus, we are able to
| make progress in these areas by simply pouring in huge amounts
| of time and brainpower.
|
| On the other hand, for subjects that are more "human," we come
| pre-equipped with a large number of instinctive insights; or to
| put it another way, we're burdened with a huge number of innate
| biases. These are mostly shortcut heuristics that only vaguely
| approximate the truth, and are deeply and unavoidable biased in
| ways that we ourselves are blind to. Thus, no matter how much
| time and brainpower we pour into these subjects, progress
| remains slow and theories remain poor.
|
| It's a well-known theorem in machine learning that an ensemble
| of weak (only slightly better than random chance) but unbiased
| learners will eventually converge to a strong learner, but a
| collection of biased learners will never become unbiased unless
| their biases are all uncorrelated. In humans, of course, the
| biases are shared across all members of the species so do not
| cancel out in this way.
| mensetmanusman wrote:
| That's mostly because complexity can't be wrapped up in
| simple rules. Physics is easier because it is dealing with a
| handful of particles.
|
| There isn't enough energy in the universe to calculate the
| full Schrodinger equation of a human. That tells us
| something...
| xtreme wrote:
| I agree with what you are saying, but I find it interesting
| that physics can also predict properties of planets, stars,
| and galaxies interacting over cosmic distances. At that
| scale, you can zoom out and reduce the complexity again
| back to a handful of rules.
| mensetmanusman wrote:
| This depends on how many digits of accuracy you are
| looking for. With living things, we care more than with
| hot rocks, because the entropy gradients are so much
| higher.
| BobaFloutist wrote:
| Right, and a big enough crowd of people behaves like a
| fluid.
| Workaccount2 wrote:
| To be fair, humans, with all their ego, simply call hominid
| intelligence "general".
| catanama wrote:
| It's actually debatable given our capability for abstract
| thought and creating things like mathematics.
|
| I think it's better to say that our minds have built in
| optimization for some patterns of behavior and thought but it
| doesn't mean we aren't "generally intelligent".
|
| Just as if you have Turing complete language designed for
| accounting it doesn't mean you can actually write anything in
| it, even if that would be not optimal.
| PmTKg5d3AoKVnj0 wrote:
| I think that's pretty ignorant of historical materialism.
|
| Humanity itself, insofar as its brain was made possible by new
| modes of nutrient-assimilation from the environment, is
| inherently technological. Nature is updated by work.
| MiscCompFacts wrote:
| This got me thinking about the radio lab episode where they had
| to vote on which animals they thought were the smartest. The
| idea was to put yourself in the context and environment of
| these animals and see which one has developed the best
| intelligence given what senses and capabilities the animals had
| to work with. The first round is Crows vs Slime Molds. I never
| thought about it, slime molds decision making abilities to find
| food are actually really fascinating and given that it's a
| unicellular organism it's adapted suprisingly well for the
| limited resources it has. I never thought about intelligence
| relative to other organisms before.
|
| Edit: here's the link https://m.youtube.com/watch?v=4YtbQkzLo1E
| limit499karma wrote:
| According to a few (related) mystical schools of thought (that
| share a boundary with Jungian psychology) there is a
| distinction to be made between _mind_ and _intellect_. The
| former, the mind, is held to be effectively a super-sense and
| its content and preoccupations naturally (as with the elemental
| senses) are bound firmly to the _body_. The intellect however
| is seen as the realm of _knowledge_ whose domain extends to the
| _transcendent_.
|
| While our _intuition_ is indeed informed by _experience_ it
| should be understood that _speculative meditations_ (should one
| care not to believe in _inspiration_ "from _above_ ") can
| enrich mental content and provide structural elements for
| _conceptualization_ that transcends _ordinary perception_.
|
| So the intellect is indeed superior to mentation. And for many
| of us this distinction is informative of our belief in the
| incompleteness of our self-perception.[..]
| flowingfocus wrote:
| Yes, our models are never complete. As someone here already
| wrote: "all models are wrong, some are useful".
|
| What makes me optimistic here is that since the enlightenment we
| have a good track record with arriving at better and better
| models. In the language of David Deutsch: We are arriving at
| better and better explanations, where the quality of an
| explanation is determined by rigidity ("how hard it is to vary")
| and reach ("in how many situations does it apply"). His books
| "The Fabric of Reality" is a great book by the way, he describes
| how the theories of evolution, quantum physics, epistemology and
| the theory of computation are connected with each other. The bit
| about good explanations is from "The Beginning of Infinity", also
| a very good read.
| sampo wrote:
| From 1954 to 1975, theoretical physics created the standard
| model of particle physics. Experimental verification of the
| theory continued through 1980s and 1990s, and finally the Higgs
| boson in 2011.
|
| But if we follow the dictionary definition of scientific theory
| "A coherent statement or set of ideas that explains observed
| facts or phenomena and correctly predicts new facts or
| phenomena not previously observed" or "a hypothesis confirmed
| by observation, experiment etc.", then after the 1970s,
| theoretical physics about the fundamental building block of
| reality hasn't really been _theoretical_ physics, but rather
| _hypothetical_ physics. They have worked on lots of theories
| (or rather: hypotheses) that they have not been able to test
| and verify experimentally.
| alexpc201 wrote:
| Most likely, the nature of consciousness and reality are rigged
| in such a way that we cannot use our consciousness to decipher
| them. Any progress in that direction is useless and, at this
| point, almost ridiculous.
| librasteve wrote:
| Thanks to Vijay for a thought provoking post. I like the
| juxtaposition of quantum gravity and neuroscience.
|
| I think that it carries two messages, one trivial and one deep.
|
| The trivial one is that physics builds on the human nature to
| build concepts. Both a jaguar and a quark are ideas that we
| extract from our perceptions, that we share with others and that
| help us to model and predict the world - quarks just need a more
| expensive microscope like the LHC. Sure eagles and prawns may
| have slightly different versions of concepts since they have
| different colour perception, but only marginally so.
|
| A practical fellow like a physicist will be clear that when the
| concepts can make measurable predictions they are worthwhile (we
| call this meta concept "real"). It is not possible to store the
| full state of or compute the evolution of anything macroscopic to
| full precision - such as the positions and momenta of all the
| particles in a table. So concepts are the only things we can know
| about reality.
|
| They argue that we may never be able to attain the deep
| underlying reality - either because it is theoretically
| unattainable or that we will continue to be resource limited. I
| contend that this dichotomy is false. It just may never be
| possible to attain deep underlying reality. The best we can do
| until we get there is to find some probabilistic rules that work
| in a pragmatic sense and to refine these tools over time.
|
| [That's pretty much a restatement of the Copenhagen
| interpretation of 1922].
|
| The deep one is that we are probably looking down the wrong end
| of the telescope. As far as I can tell (from popular
| neuroscience) is that our ability to model the perceptual /
| conceptual processes and how they compose into intelligence
| remains in the dark ages.
|
| But, given that we each have 70 billion neurones or so, there is
| a lot of classical physics going on in our heads to make these
| concepts and we have practically no hard, proven theories about
| how this works. We are doing layers of pattern recognition and
| extraction and feedback that allows us to avoid being eaten by
| Jaguars.
|
| So let's get a proper theory of intelligence. One that let's us
| work out which aspects of quantum mechanics are philosophically
| necessary to sustain our subjective experience of space and time.
| With a substrate with branching / collapsing features. Where time
| has an arrow with memory in the past and uncertainty in the
| future. Where cause and effect are loosely coupled. Where there
| is a notion of free will.
|
| Some endnotes: - The quantum measurement problem is perhaps a
| limit of this theory - Perhaps the notion of computational
| reducibility is a stab in this direction [Wolfram] - Probably all
| you need is emergence for this and not a quantum brain [Penrose]
| Vecr wrote:
| > Where there is a notion of free will.
|
| > Perhaps the notion of computational reducibility is a stab in
| this direction [Wolfram] - Probably all you need is emergence
| for this and not a quantum brain [Penrose]
|
| Well, yes, but I'm not sure you can have both of those at the
| same time without getting very clever. You'd need to make a
| version of compatibilism that's not just the next in a long
| line of increasingly convoluted magic shows.
| throw7 wrote:
| Science is an open system. Everything is open to being
| "wrong"/"updated". There is nothing that grounds the system. You
| must be always open that your prediction of unobserved things
| will be wrong. To actually believe that science will one day
| solve the great mystery of the universe is scientism.
| jfactorial wrote:
| Is there any stronger tool for rational truth seeking than the
| scientific method?
|
| Observe. Hypothesize with falsifiable statements. Form
| experiments that could disprove the falsifiable statements.
| Observe. Publicly make falsifiable statements to peers capable
| and incentivized to disprove them.
|
| How can this fail to lead us to truth that is as close to
| objective as possible? What greater method exists?
| bubblyworld wrote:
| This is a little bit out there from a rationalist point of
| view, but I think there are domains in which not all of the
| requisite concepts for the scientific method actually exist.
| An example that comes to mind is the nature of conscious
| experience - having spoken to a lot of meditators, for
| instance, I'm convinced that there really are commonalities
| to it that you can experience yourself by sitting down and
| paying attention. But I don't think there's anything to
| really falsify here, because there's nothing to measure!
|
| You can't tell someone "here's this totally objective way you
| can pick apart your conscious experience into a bunch of
| statistics, and when you do change X I predict you'll see the
| statistics vary like Y". You can kinda just point their brain
| in a direction and hope that they experience it for
| themselves.
|
| Another example, I think, is domains that are under
| optimisation pressure or control of some kind (like an
| ecosystem, or much more simply a thermometer). There was a
| post on HN a few days ago about causality, and how the
| standard statistical methodologies for determining causality
| kinda break down when you start measuring systems like this.
| Correlation is not causation, but in these systems causation
| no longer necessitates correlation either! Perhaps a
| different kind of epistemology would be useful here too.
|
| Anyway, not sure this is making sense. Would be curious to
| hear your thoughts.
| itishappy wrote:
| > Science is an open system.
|
| To date, but I doubt this is a law of nature. What prevents the
| next big discovery from being the final piece that grounds the
| system making everything else fall into place?
| digging wrote:
| This is a semantic debate, but "science" is the process of
| finding those rules. If we find an "ultimate" rule, we're
| still using science. (Assuming science is capable of finding
| that ground truth rule.)
| itishappy wrote:
| I assumed "open system" here meant there is no ultimate
| rule, implying science can continue indefinitely. This
| aligns with our experience so far, and it does feel right
| to me, but I don't think we have evidence either way.
|
| I completely agree that the scientific process is our
| best/only tool for meaningfully advancing our understanding
| of the world.
| goatlover wrote:
| Reality/nature/the world grounds science. Whether it can all be
| figured out depends on whether that information is contained
| within the universe. Are you prepared to say an advanced
| civilization millions of years old doesn't know the "great
| mystery" of the universe? It's a little premature.
| __rito__ wrote:
| The Indian Philosopher that is gravely missing from the article
| is Nagarjuna. The kinds of questions the author raises, the path
| he is treading on, will benefit from the study of Shunyata
| Philosophy of Madhyamika school, especially Nagarjuna.
|
| I am not alone in thinking this. I was surprised to see Carlo
| Rovelli talking about it in multiple occasions.
|
| Heres one [0].
|
| Nyaya and Madhyamika Philosophies still have many lessons that
| are not yet discussed in the spotlight.
|
| [0]: https://m.youtube.com/watch?v=CgIfNuZs56w
| ziofill wrote:
| I am a theoretical physicist, and I am very much in tune with the
| author. Take quantum mechanics (my field), it is clear that even
| though we have a working model of it, it doesn't explain _how_
| nature instantiates it. Entanglement is a prime example of this:
| I know exactly how to describe it, but nobody has a clue of how
| it works. In other words, physics is a mostly coherent and
| certainly useful story about reality, but it isn 't grounded on
| "bedrock" reality, rather on our perception of it.
| BobaFloutist wrote:
| Correct me if I'm wrong, but I think of entanglement as less
| forming an actual binding relationship to two particles, and
| more as setting them up exactly the same way.
|
| So it's not that you have two magnetic marbles and rotating one
| rotates the other, it's that you're rolling two dice with
| identical parameters and can expect that at any given slice of
| time they'll be doing the same thing.
|
| Is that incorrect?
| nathan_compton wrote:
| Entanglement is neither a bond between two objects nor a
| setting up of two objects in the same way. Entanglement
| derives from the fact that quantum mechanical systems have
| properties which are non-local with respect to the "process"
| of measurement that do not depend on the physical size of the
| system in question. Its actually suspect to say that
| "particles" are entangled at all - the entanglement is a
| property of the wave function in which the particles
| identities are (with respect to the quantity that is
| entangled) indistinct.
| ziofill wrote:
| Yes you're on the right track: there isn't any 'action'
| between the two systems, it's a correlation. However, here's
| the thing that fries my brain: for classical systems
| correlation means the pre-existing value of some property is
| correlated (e.g. if I take a random glove out of a pair, the
| moment I look at the one I picked I know the handedness of
| the other). In the quantum case there isn't a pre-existing
| value for the property you're measuring (because you're free
| to pick the measurement basis), and you can't say one
| measurement outcome caused the other because you can set up
| the measurements to happen outside of each other's light cone
| (so you are free to pick which measurement happens first by
| changing reference frame).
|
| So: how does particle A "know" how to produce the correct
| correlation if 1) the value is produced 'on the spot' and 2)
| there isn't a well-defined causal order between measurement
| of A and B?
| ChrisClark wrote:
| Basically, could I say something like, QFT is about fields, but
| what are the fields, are they in something, are they self
| instantiated, what makes the fields?
|
| We can describe the fields, but we can't get behind them, the
| how and why? At least we can't get behind them yet, but if we
| do, do we know the how of that or is it just another layer?
| jebarker wrote:
| I'm not a physicist. An idea from physics that I recently learned
| and found very unnerving was that the solid objects we see and
| feel in the world are actually mostly empty space. We just see
| them as solid because of the way light interacts with the
| particles. So in a sense our visual and tactile perception of the
| world is just one representation of the underlying reality and
| you can imagine there being infinitely many other possible
| representations.
|
| I'm just crudely saying the same thing as the author I think, but
| I wanted to emphasize how uncomfortable this makes me. In some
| sense it feels like being a prisoner in a perceptual cell you
| can't escape from surrounded by a reality you'll never know.
|
| Having philosophy as a counterpoint (in my case dabbling in
| Buddhism) has been essential to keep me calm and relaxed.
| biggoodwolf wrote:
| You're a brain in a bucket. What is the nature of the bucket is
| up for debate
| goatlover wrote:
| Your brain is part of a nervous system that extends
| throughout the "bucket". Body and brain aren't really
| separate.
| jebarker wrote:
| I think the bucket is bigger than just your body.
| nathan_compton wrote:
| This is more of an intellectual parlor trick than anything
| else. Like literally what else could "solid" mean besides "that
| which we call solid based on our perception." When you say that
| matter is "mostly empty space" you are really writing is a
| sentence which implicitly uses two definitions of solid in one
| place without distinguishing between them.
| jebarker wrote:
| But we have a common understanding of what "mostly empty
| space" looks like and what we perceive as solid objects don't
| look like it.
| nathan_compton wrote:
| Solid objects look exactly like what we perceive solid
| objects to look like. That is kind of the point.
| nathan_compton wrote:
| I think I can be more clear. When you refer to what
| something looks like you are referring to the way we
| perceive things, which is with electromagnetic waves. In a
| very real sense, with respect to that, (that is, with
| respect to the electromagnetic field), solid objects really
| aren't "full of empty space," they are chock full of
| electromagnetic fields. Like the idea of "empty" is
| actually just sort of not a great way of thinking about
| small stuff. In fact, if we want to operationalize our
| notion of full or empty, we'd probably end up back at our
| intuitive notion of the idea.
|
| For example. We might say that a helium atom is "mostly
| empty space" because if we measured the position of one of
| the electrons it would tend to be far away from the other
| one (maybe the right way to think of this is to look at the
| spread of coherent position states). But, in fact, around a
| helium atom the electrons interact pretty strongly (enough
| to distort their wave functions substantially) so in that
| sense the region around a helium atom is significantly
| _less_ empty than the space around the sun between (say)
| mercury and venus, which have very little effect on one
| another. What I am getting at is that all this idea of
| "atoms are mostly empty space" gets at is that our
| definition of "empty space" is pretty vague. Vague enough
| to do some silly word gymnastics.
| whatshisface wrote:
| Electrons meaningfully fill up the space in materials at low
| frequencies but not at high frequencies. So you can be... half
| calm?
| nh23423fefe wrote:
| why is this unnerving? fog isnt transparent while air is and
| since these are gases they are "emptier" than solid things. the
| emptiness properties is disconnected from visual or tactile
| properties.
|
| i cant understand what you mean by knowing reality. reality is
| sui generis and knowledge is a relational concept.
| nonameiguess wrote:
| "Solid" doesn't really have meaning at the sub-molecular level.
| All space has something in it, even if it's just vacuum energy.
| Virtual particle pairs come and go all the time. Some space has
| particles with electromagnetic charge. Each of these has some
| interaction radius. Technically, this is infinite. Electric
| field reaches everywhere, but thanks to inverse square law,
| only other particles within some much smaller radius than
| infinity will interact with enough force to change velocity
| noticeably. Gather together a large enough collection of these
| into chemically bonded distinct macroscopic objects, and there
| you go. The radius at which particles are repelled from each
| other is smaller than the distance between these bonds. That's
| all "solid" means.
|
| Whether particles truly have any material extent at all, or are
| simply literal points representing the center of various
| interaction radii, is unknown and probably unknowable. It's not
| even clear what the difference would mean. Can a particle
| somehow "take up space" and prevent another particle from
| occupying that space if it interacted with no force at all? I'm
| not a physicist and kind of talking out of my ass here, but I
| think the Pauli exclusion principle implies maybe, but it
| doesn't apply to all particles.
|
| Human perception relies entirely upon electromagnetism. Once
| you get down to distances less than the wavelength of the
| highest frequency photons and electrons, we can probe and
| describe the relationships mathematically, but I don't think it
| makes sense to try and conceive of what these things "are" in
| some greater ontological sense. We inherently analogize to what
| things look and feel like, but looking and feeling like
| anything is a higher-level emergent phenomenon of
| electromagnetic interactions.
| wigster wrote:
| i can't read that due to the bobbing header. atrocious design.
| michael9423 wrote:
| How can he be sure he's a theoretical physicist if he doesn't
| know reality exists at all?
|
| The truth is, instead of reality, he would be better off
| questioning theoretical physics, which indeed does not exist
| outside the heads of academia.
|
| His "questioning of reality" only happens philosophically (in
| other words, it is an academic farce), once he gets up to do some
| grocery shopping he sure knows what to buy so he can eat in order
| to survive. There is your objective reality.
|
| Humans understand reality if they do not bury their heads in the
| sand. But academia can get in the way.
| analog31 wrote:
| Disclosure: I'm not a theoretician, but just an old industrial
| physicist who helps design measurement equipment.
|
| What I've noticed is that most physicists are aware of the great
| epistemological puzzles, and may even have briefly dabbled in
| them, but also tend to ignore them if there's work to be done.
| There's a lot of pleasure and utility to be gained from just
| finding a hard problem and working on it, maybe even solving it,
| or inventing something.
|
| When people find out that I'm a physicist, and ask me about those
| puzzles, I usually plead ignorance. I'm not dismissive of them,
| or anti-intellectual, but I think you shouldn't let them be an
| obstacle to the enjoyment of physics, either as a spectator or
| practitioner.
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