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What If Time Really Exists? (2008)

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Re: What If Time Really Exists? (2008)

#181

Post by alphydan »

andrepd wrote: post #137
tomphoolery wrote: post #128

Earlier quoted context omitted.

To me, it seems like evolution. Because when you get down "to the metal" of the universe, it's really just a bunch of dirty hacks that are thrown together and give off the illusion of uniformity and grace. The way things work at a macroscopic level seem so grand and ultimate, but on the microscopic level of all that it's utter chaos. Random acts of chemical bonding happened to create the life forms we interact with e…

I'm curious, how can you be a "big believer" in something that is entirely made up with absolutely no evidence of any sort to back it up? And how do you mean, dirty hacks. Our fundamental physics nowadays is quite elegant, I'd say, and still we have many questions still to be answered and much deeper to delve till we hit the "bare metal". We've only been in the universe-figuring-out business for real for about 200 ye…

> I'm curious, how can you be a "big believer" in something that is entirely made up with absolutely no evidence of any sort to back it up?

7,100,000,000 people seem to find it quite easy [0] (although I'm not one of them)

[0] https://en.wikipedia.org/wiki/List_of_religious_populations

Re: What If Time Really Exists? (2008)

#182

Post by naasking »

j2kun wrote: post #172
naasking wrote: post #150

Earlier quoted context omitted.

It doesn't sound like you've read Bostrom's simulation argument: http://www.simulation-argument.com/simulation.html

Oh I've read it. It's a fun game to read through it and write down all the unfounded assumptions the author makes. It also doesn't help that his ideas about the complexity of the human brain are sorely outdated.

No unfounded assumptions that I can see. Bostrom is quite explicit and thorough in documenting his assumptions, and his conclusion is undeniable.

Re: What If Time Really Exists? (2008)

#183

Post by j2kun »

naasking wrote: post #182
j2kun wrote: post #172

Earlier quoted context omitted.

Oh I've read it. It's a fun game to read through it and write down all the unfounded assumptions the author makes. It also doesn't help that his ideas about the complexity of the human brain are sorely outdated.

No unfounded assumptions that I can see. Bostrom is quite explicit and thorough in documenting his assumptions, and his conclusion is undeniable.

If you cannot convincingly argue the opposing side, then you have not thought hard enough about it. If you have no room for doubt, then there is no point discussing it. You have reduced science to zealotry. Don't waste my time.

Re: What If Time Really Exists? (2008)

#184

Post by gus_massa »

lohankin wrote: post #168
gus_massa wrote: post #115

Earlier quoted context omitted.

> Quantum physics looks a lot like lazy evaluation (State doesn't exist until "observed"). This is a common misconception (¿among programmers?). Let's think about the double slit experiment. https://en.wikipedia.org/wiki/Double-slit_experiment In a classical word, you must simulate only one path. In a quantum word, you must simulate both. You don´t need some magical conscious observer to force the collapse of the wav…

> In a classical word, you must simulate only one path. In a quantum word, you must simulate both. You don´t need some magical conscious observer to force the collapse of the wave function. A CCD detector of a camera or a simple wall is enough to force that the "wave" collapse into a "particle" and the detector or wall gets a small spot where the "particle" hits it. This is a common misconception (among programmers).…

> Circumstances under which wave function collapses is the greatest mystery of QM.

I agree with that.

Anyway, if you have an optical system, you can assume that coherence is present while the light hits mirrors, lens and similar optical equipment. (If the difference in the optical paths are smaller than the coherence length of your laser or light source.) But as soon as the light hits a white screen or a brick wall, all the further calculations must use only the intensity of the light at each spot in the screen, forgetting about the phase angle. And all the spots are not coherent.

It's not clear what cause the wave function collapse, but if you are using photons in the visible spectrum probably a mirror will not collapse it, and a brick wall will collapse it. [Or your preferred rewrite with the multiple word interpretation, or the abstract Hilbert space calculations.) I'm guessing decoherence is the correct explanation, there is a nice comment in a reply.

For other particles, the abstract calculation is equivalent, but it's necessary to choose another system to do the experiments.

Re: What If Time Really Exists? (2008)

#185

Post by naasking »

j2kun wrote: post #183
naasking wrote: post #182

Earlier quoted context omitted.

No unfounded assumptions that I can see. Bostrom is quite explicit and thorough in documenting his assumptions, and his conclusion is undeniable.

If you cannot convincingly argue the opposing side, then you have not thought hard enough about it. If you have no room for doubt, then there is no point discussing it. You have reduced science to zealotry. Don't waste my time.

So you wasted your own time by posting without pointing out even a single example of such an unfounded assumption?

Re: What If Time Really Exists? (2008)

#186

Post by j2kun »

naasking wrote: post #185
j2kun wrote: post #183

Earlier quoted context omitted.

If you cannot convincingly argue the opposing side, then you have not thought hard enough about it. If you have no room for doubt, then there is no point discussing it. You have reduced science to zealotry. Don't waste my time.

So you wasted your own time by posting without pointing out even a single example of such an unfounded assumption?

You have already made it clear that you think his argument is undeniable. But since you insist on trolling, let me start with the obvious one.

In order to simulate a human brain, you need to simulate physics. Not a mathematical model of physics, but the actual true process that governs nature. In order to do that, you need to (1) understand the true laws of physics and (2) the process needs to be simulatable in polynomial time (at the very least). Where in the essay does he give you a convincing argument that these are true? Or is it just the lack of impossibility enough to convince you that they are possible?

Re: What If Time Really Exists? (2008)

#187

Post by gpsx »

dghf wrote: post #114
Jizzle wrote: post #89

Earlier quoted context omitted.

It's the most obvious counter-interpretation. I think it's become remarkably successful, but also suffers in its embrace of causality. While the Copenhagen interpretation can skirt the issue completely, Bohm's must wrangle with the implications of both relativity and non-locality and no one has been completely successful as such. Also, if it were the leading view, I don't think discussions of a simulated universe wou…

> It's the most obvious counter-interpretation. More obvious than many worlds?

Yes. Many worlds is the single obvious solution. It seems some people don't understand many worlds though. Or maybe there is some other definition I am not aware. I want to describe my understanding here for people's benefit.

The idea is that when you make an observation nothing special happens at all. For one, there is no wave function collapse. This is more an idea about how the observer experiences making a measurement. The salient feature is that the observer is not external to the system. He is a part of the system. His belief that the result was heads or tails is coincident in the wave function with the coin being heads or tails. In other words, the user becomes entangled with the system.

A toy wave function would look like this (I am leaving off normalization since I can't write a square root of 2):

Coin flip result, no observer: |heads> + |tails>

Coin flip with observer, "Tom": |heads>|Tom: it was heads> + |tails>|Tom: it was tails>

There is no collapse here. However, to Tom it appears as if the world did collapse. For the "version" of him that thinks the coin flip came up heads, his entire world is consistent with the measurement coming up heads.

I assumed most people who really understand quantum mechanics believe this (but I may be wrong). And that among them, there is no effort to say "There is no collapse" because indeed the effective result of the measurement is a collapse. I also use the language "wave function collapse" to describe what happens. This not because it is an objective reality of the universe but because it is the way we observe the universe.

Re: What If Time Really Exists? (2008)

#188

Post by thinkloop »

witty_username wrote: post #175
semi-extrinsic wrote: post #102

Earlier quoted context omitted.

In relativity we can model time as a dimension, with great success. But even there it is always evident that the time dimension is very different from the spatial ones; for one, we cannot travel in it. I believe GP is only saying this is the problem, ignoring that the time dimension is very special.

We can travel in it. We all are travelling in time and at different rates depending on our speed and gravity.

That's the sci-fi terminology and view that complicates and confuses the issue. Can reactions happen faster or slower, yes. No need to say "travel", that word has distinct meaning and connotations that lead to incorrect possibilities.

Re: What If Time Really Exists? (2008)

#189

Post by baytrailcat »

phkahler wrote: post #129
baytrailcat wrote: post #54

Earlier quoted context omitted.

Are you entirely sure about that? There has been some solid efforts to explain collapse - like Ghirardi–Rimini–Weber theory

Nothing changes at the time of "wave function collapse". When you measure one particle of an entangled pair, nothing actually happens to the other one. But you don't need to listen to me, check this out: https://www.youtube.com/watch?v=dEaecUuEqfc

The wave function collapse and "spooky action at distance" for entangled particles are somewhat different concepts. The collapse idea arises as a part of Copenhagen interpretation, which states that particle always exists in a superposition state (aka wave function of probabilities). So when audience asks, "well why is it that my measurement device showing particle exists/doesn't exist in one place"? The interpretation then says, "That, my dear fried, is because the wave function collapsed to a single state just when you did the measurement". People have been trying to explain and figure out what/why/when this collapse occurs to make sense of Copenhagen interpretation.

Re: What If Time Really Exists? (2008)

#190

Post by Alex3917 »

School-Cotton wrote: post #69
Alex3917 wrote: post #11

Earlier quoted context omitted.

> It's very nearly a religion. I'd argue it is a religion. The word religion means to "bind back" or "yoke" [edited], i.e. to seek an understanding of the universe and our place in it. That's what physicists and cosmologists do. These disciplines also fulfill the needs of scientists for meaning and community and ritual, not unlike Christianity or Islam or whatever. Just because you might happen to believe something d…

Arguing based on etymology is a logical fallacy.

In this case, as I've documented, the way many modern religious studies people use the word is closely aligned with the etymology I gave. Whether that etymology is historically accurate has been disputed, but the fact that people use the word to mean basically the same thing as the purported etymology is not.
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