Carlo Rovelli on the ‘greatest remaining mystery’: The nature of time • Hacker News Board

Re: Carlo Rovelli on the ‘greatest remaining mystery’: The nature of time

#111

Post by boffinism » Sat, Jun 23, 2018, 10:26 AM UTC

Maro wrote: post #101

Disclaimer: I'm a physicist who didn't finish the Phd and went to work in the tech field instead. I wish physicists would stop writing these bullshitty popular science books. A lot of the books are popularizing unverified / unverifiable things like String Theory or Multiverse or Arrow of Time. And when they're talking about more plain things like Special Relativity, then I still cringe, because it's not something tha…

> it's not something that's worth explaining to lay people

Lay person here. I'd just like you to know that we experience curiosity too. Also, having read some Rovelli, I should point out that he's pretty good at highlighting when and how he's simplifying, and flagging up when he strays beyond the scientific consensus into the unverified.

Re: Carlo Rovelli on the ‘greatest remaining mystery’: The nature of time

#112

Post by Maro » Sat, Jun 23, 2018, 10:31 AM UTC

hansen wrote: post #108

jpmoral wrote: post #103

Earlier quoted context omitted.

> there is no situation in which some high-level bullshitty understanding of GR or SR or QM will be helpful or relevant in life, at best it will confuse you. If I only learned and experienced things that would be 'helpful' or 'relevant' it would be a very dull life.

Yeah, science isn’t about being useful and relevant in day to day life. It’s an important part of human culture and scientist should at least try to communicate their findings to general public (which is paying for it!). I partially agree with the first comment that it isn’t really helpful to popularize highly speculative – and thus probably false – ideas. But well established but still “weird” discoveries like GR &…

I respect your point of view, but I don't really agree.

A popular science understanding of BHs, BB, QM is not really an understanding. It's just some fairy tale level understanding. To be clear, I'm not being elitist, using QM as an example, I think it was Feynman who said nobody really understands it, at best we can make calculations/predictions ("shut up and calculate").

For example, ask a lay person about BB and they will tell you it's an explosion, in the classical sense (it's not). Or, I don't think you can "understand" QM without understanding the significance of unitary linear operators for time evolution, or self-adjoint linear operators for measurements. If you would "allow" non-linearities, the world would be different.

Re: Carlo Rovelli on the ‘greatest remaining mystery’: The nature of time

#113

Post by aroberge » Sat, Jun 23, 2018, 10:38 AM UTC

GnarfGnarf wrote: post #81

Time does not exist. It is an abstraction based on the movement of matter. We use time to compare the relative motions of things. Every instrument we use to "measure" time involves movement: pendulum, sandglass, rotation of Earth, translation of Earth around the Sun, vibration of atoms, etc.

Wow ... Since you are so certain that time does not exist, why don't you write a paper showing the implications for quantizing gravity, and why the standard spacetime picture of both Special and General relativity is wrong?

Re: Carlo Rovelli on the ‘greatest remaining mystery’: The nature of time

#114

Post by beesmum » Sat, Jun 23, 2018, 10:38 AM UTC

perl4ever wrote: post #77

beesmum wrote: post #24

Earlier quoted context omitted.

While I think it's an interesting argument, I don't agree that accepting that some other being than me can be conscious leads to having to accept the physical origin of consciousness a priori. If you look at Buddhism or any esoteric system, they essentially posit that consciousness is a unified field from which everything manifests, like light refracted through an (infinitely) complex array of lens. The spots of ligh…

Are you or are you not experiencing my consciousness right now? Either you claim to, in which case you're lying or delusional, or you don't claim to, in which case you can't say anything about its experiential nature without contradiction. I can say I am conscious all day, but that's just something I say - it can't prove anything to you. If I was being tortured, and I didn't communicate it to you, would you notice? L…

I think you capture what I was referring to when I said that limited awareness is what narrows consciousness -- it's like putting some of the ocean in a bucket. It's still part of the ocean, but it's not the whole ocean. What do logic and labels like solipsist and materialist have to do with consciousness? Yes, they're part of consciousness, but they're a construct: concepts and words that we're using to discuss our own unique experiences of consciousness. We can chase each other around forever in a rabbit hole of semantics about what the nature of consciousness is, and how my experience varies and is separate from your experience of it, but we're just looking at our buckets of water that we scooped up as if it's the entirety of the ocean. Meanwhile, the ocean is sloshing around us. It doesn't rely on us to be aware of it's oceanness to exist, it just is. Consciousness has more than enough space to accommodate your experience that relies very heavily on logical coherence to form a version of reality that is comfortable for you to function in, but that experiential frame isn't the ground of all being. It's just a lens that one can look through. Sure, I can't share you're exact experience, but I could empathize with you if I knew you were tortured. You can look through one lens and then another: consciousness is constantly changing and modulating our experiences, there's nothing static about it.

Re: Carlo Rovelli on the ‘greatest remaining mystery’: The nature of time

#115

Post by [deleted] » Sat, Jun 23, 2018, 10:39 AM UTC

jerf wrote: post #65

_8j50 wrote: post #54

Earlier quoted context omitted.

I was defining time as the measurement of change. Change does not depend on measurement therefore there is no circular definition. For example, a star is different from star light. When I look at the sky through a telescope I don't see a star,I see star light. Same can be said for any object as well,we see light emanating from an object therefore vision is perception of an object as measured by our optics. Time is ho…

The problem is that if you take the time and carefully consider all of your statements, and carefully lay them all out in a row in the right way, you will find you've got circularity hiding in them. I am confident in this statement because you are walking very well-covered ground, and lots of smart people have examined it all very closely. For instance, "change" intrinsically has a before and after element in it; you…

[deleted]

Re: Carlo Rovelli on the ‘greatest remaining mystery’: The nature of time

#116

Post by dempseye » Sat, Jun 23, 2018, 10:41 AM UTC

Maro wrote: post #112

hansen wrote: post #108

Earlier quoted context omitted.

Yeah, science isn’t about being useful and relevant in day to day life. It’s an important part of human culture and scientist should at least try to communicate their findings to general public (which is paying for it!). I partially agree with the first comment that it isn’t really helpful to popularize highly speculative – and thus probably false – ideas. But well established but still “weird” discoveries like GR &…

I respect your point of view, but I don't really agree. A popular science understanding of BHs, BB, QM is not really an understanding. It's just some fairy tale level understanding. To be clear, I'm not being elitist, using QM as an example, I think it was Feynman who said nobody really understands it, at best we can make calculations/predictions ("shut up and calculate"). For example, ask a lay person about BB and t…

> It's just some fairy tale level understanding.

This has value in itself, as the first step towards greater understanding. I bet most people who study physics had their interest piqued by such fairytales. Maybe you did too.

Re: Carlo Rovelli on the ‘greatest remaining mystery’: The nature of time

#117

Post by hansen » Sat, Jun 23, 2018, 10:45 AM UTC

Maro wrote: post #112

hansen wrote: post #108

Earlier quoted context omitted.

Yeah, science isn’t about being useful and relevant in day to day life. It’s an important part of human culture and scientist should at least try to communicate their findings to general public (which is paying for it!). I partially agree with the first comment that it isn’t really helpful to popularize highly speculative – and thus probably false – ideas. But well established but still “weird” discoveries like GR &…

I respect your point of view, but I don't really agree. A popular science understanding of BHs, BB, QM is not really an understanding. It's just some fairy tale level understanding. To be clear, I'm not being elitist, using QM as an example, I think it was Feynman who said nobody really understands it, at best we can make calculations/predictions ("shut up and calculate"). For example, ask a lay person about BB and t…

> For example, ask a lay person about BB and they will tell you it's an explosion, in the classical sense

Give her Weinberg’s book to read and she’ll come to a different conclusion. Of course those books won’t give you a deep understanding of cosmology but that doesn’t mean they have to be completely wrong. Stephen Weinberg’s The First Three Minutes is my favorite example of pop-sci done right.

Re: Carlo Rovelli on the ‘greatest remaining mystery’: The nature of time

#118

Post by aroberge » Sat, Jun 23, 2018, 10:55 AM UTC

uh_what wrote: post #91

acqq wrote: post #78

Earlier quoted context omitted.

> humble 2 cents Sadly, not humble, and, from my point of view, uninformed, that is, exactly what would be expected from an otherwise uninformed reader of the newspaper articles about the topics touched, especially from one not understanding how science actually works. In reality, the "failed" fulfillment of some expectations when the best experiments up to now are performed is also what advances our knowledge, great…

Your post kind of rambles on and fails to address the point that OP is making: Physics is, in fact, stuck. It's been almost 100 years since the initial clash between classic mechanics and quantum theory, and how much closer are we to unification? And you take an extremely condescending tone while addressing OP's lack of humility while making statements attacking him for "especially from one not understanding how scie…

> It's been almost 100 years since the initial clash between classic mechanics and quantum theory, and how much closer are we to unification?

There is no problem with, to use your words, unification of classical mechanics and quantum theory

Classical Mechanics is recovered from Quantum Mechanics in the limit of h-bar (Planck's constant) goes to zero. In our day to day experience, Planck's constant is so small as to effectively be zero. The non-intuitive effects of Quantum Mechanics occur when we probe areas where the non-zero value of Planck's constant cannot be ignored.

There has been enormous progress in the last 100+ years in understanding how the world is described by Quantum Theory. In some ways, the so-called Standard Model of Particle Physics can be seen as the crowning achievement of that work.

The only remaining question on that front is the absence of a testable theory that describe gravitation as a quantum theory. String Theory appears to be a leading candidate for this, but it has not, so far, made any testable prediction outside of what we already know from other theories.

Re: Carlo Rovelli on the ‘greatest remaining mystery’: The nature of time

#119

Post by oldandtired » Sat, Jun 23, 2018, 11:04 AM UTC

hansen wrote: post #108

jpmoral wrote: post #103

Earlier quoted context omitted.

> there is no situation in which some high-level bullshitty understanding of GR or SR or QM will be helpful or relevant in life, at best it will confuse you. If I only learned and experienced things that would be 'helpful' or 'relevant' it would be a very dull life.

Yeah, science isn’t about being useful and relevant in day to day life. It’s an important part of human culture and scientist should at least try to communicate their findings to general public (which is paying for it!). I partially agree with the first comment that it isn’t really helpful to popularize highly speculative – and thus probably false – ideas. But well established but still “weird” discoveries like GR &…

The problem with the "well established" or "settled" discoveries is that there is enough experimental evidence that is anomalous to the theories thus presented. This effects everything from the ideas from General Relativity, Special Relativity, Big Bang, Quantum Mechanics, the Standard Model of Particles, etc.

I think the biggest problem that is faced today (it hasn't really changed in centuries) is that people do not like to be considered ignorant, especially those who delve into such matters at a professional level. We actually know so little of the universe around us, but as humans, we do not like to acknowledge that we don't know.

The fact that we don't know and that our current suite of theories is incomplete and hence could very well be wrong in both minor and major ways should be driving us onward into understanding the universe around us. It really is not a problem if we don't understand. It should mean that we strive to learn more.

However, far too often, I find that the supposed knowledgeable ones exhibit an attitude of superiority that effectively closes them to a better understanding. There are those of course who are humble enough to say that they actually have little understanding even though they are at the very top of their respective fields.

Being able to be honest and say that one doesn't know is the first step on the road to acquiring some semblance of understanding. Being able to explain to someone else what the current understanding is in a simple enough manner is a good step on the way to increasing one's own knowledge.

Re: Carlo Rovelli on the ‘greatest remaining mystery’: The nature of time

#120

Post by resource0x » Sat, Jun 23, 2018, 11:12 AM UTC

GnarfGnarf wrote: post #81

Time does not exist. It is an abstraction based on the movement of matter. We use time to compare the relative motions of things. Every instrument we use to "measure" time involves movement: pendulum, sandglass, rotation of Earth, translation of Earth around the Sun, vibration of atoms, etc.

The most surprising fact is that the readings of all these instruments are in sync with each other! We take it for granted, and don't appreciate the mystery. It very well might be that the Universe forms a complex landscape with varying "laws", with the pockets where the notions of space and time become quite fuzzy and inconsistent; we might live in a rare oasis where the things more or less "make sense". Elsewhere, there might be no time at all. Popular books on physics never mention this possibility.