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A delightful quirk of relativity theory

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Re: A delightful quirk of relativity theory

#91

Post by vidarh »

awb wrote: post #78
danbruc wrote: post #42

Earlier quoted context omitted.

Rescuing free-will from the jaws of spacetime would be cool! Free will does not exist. It is logically inconsistent. Either your choice is some function of your current state and the environment you are in, then the choice is not free, or it is independent of your current state and the environment you are in, then it is not your choice in any meaningful way, it is just the result of a coin flip. You can do some menta…

A few issues with the “free will” debate. 1) Define “free” 2) How do you test your hypothesis? You’re trying to apply logic to an untestable philosophical debate. If you believe free will doesn’t exist, you can’t design an experiment that would invalidate that belief. And if your theory is untestable and unfalsifiable, then what good is it other than a creative exercise? However, we do know from Quantum Mechanics tha…

> You’re trying to apply logic to an untestable philosophical debate. If you believe free will doesn’t exist, you can’t design an experiment that would invalidate that belief. And if your theory is untestable and unfalsifiable, then what good is it other than a creative exercise?

This is reversing the burden of proof. The issue with "free will" is getting those who think there is a meaningful "free will" concept to actually define what they mean.

Look through this discussion and see the comments trying to justify the existence of free will, and look for definitions of what they actually mean by that.

> However, we do know from Quantum Mechanics that the universe is probabilistic and not deterministic:

That's a meaningless distinction in this context. The point is that nobody has presented a mechanism whereby you can inject any form of agency that fits a definition of "free" (see your own point: define "free") that doesn't devolve to smoke and mirrors that way.

In order to do so, there'd need to be something that would lead to measurable biases in outcomes that can not be explained by the probabilities.

The rest of your argument devolves to Russel's teapot: As long as nobody has posited a reasonable definition that'd give rise to a theory of what free will might mean, the notion is so absurd that it is entirely reasonable to say that free will makes no sense.

If you can present a definition that can't easily be shown to be just smoke and mirrors and which somehow makes sense to people, even without coming up with ways of actually testing it, I might be tempted to moderate that claim, but I've had these discussions with people for decades, and in none of them have anyone ever managed to come up with a cohesive definition of what free will would even mean that doesn't very easily start looking distinctly "unfree".

There are clearly definitions of free will that would allow something you label with that term to exist. But I challenge you to come up with one that people would agree is both "free" and "will".

Re: A delightful quirk of relativity theory

#92

Post by whatshisface »

philipov wrote: post #83
irthomasthomas wrote: post #21

This would be more fun in a blog post. Twitter is a fucking horrible format for a complex analysis of special relativity. That aside, my favourite quirk from relativity is this: "The more you move in space, the less you move in time." Like relativity in general, it sounds simple enough, but it's consequences are profoundly shocking. (That is, if you take the time to understand it, and don't leap to the conclusion tha…

There is no room for free will in physics, period . All processes are completely deterministic. Even quantum processes might appear to be probabilistic if you look at individual particles, but the statistics are nevertheless completely deterministic: if you look at enough particles, a predictable shape will emerge. The future is set in stone and not only is there no way to change it, but the concept of changing the f…

There is no room for free will in classical mechanics. Quantum mechanics has plenty of "room for free will," because either:

1. The universe is not deterministic (if you believe that wavefunctions collapse)

2. The mysterious thing that makes conscious entities experience high-amplitude events more often than low-amplitude events is not deterministic (if you believe in MWI).

Evidence for free will, a definition of free will; those things physics cannot provide. But there's room for it.

Re: A delightful quirk of relativity theory

#93

Post by krupan »

Some people hate tweet threads like this, but I feel like it really forces concise communication and arranging thoughts into small but complete chunks. I’ve never put my thoughts into this format, but I would guess it’s actually pretty difficult and requires some careful planning to do it well, especially for a challenging topic like this. Thanks for sharing this to hacker news, sohkamyung!

Re: A delightful quirk of relativity theory

#94

Post by Retric »

Jeff_Brown wrote: post #86
awb wrote: post #61

Earlier quoted context omitted.

> Take the case of two people on Earth, one stationary and one travelling past in a car. They each have a different reference frame, and a different set events which make up their present. Now imagine that there is an alien government in Andromeda debating a possible invasion of Earth. In the reference frame of the person on Earth who is moving, the debate is still going on. But, in the reference frame of the station…

The reason the scenario posits an invasion from so far away is that that's about how much distance it takes for a small speed difference here to translate into a day long time difference there.

That’s not how it works.

But even beyond that you have the math wrong. Andromeda galaxy is only 2.5 million light-years from Earth. To get a 1 day difference in time dilation across 2.5 million years would take 1 in 913 million difference which someone traveling at even 100MPH (45m/s) isn’t going to see. (1 - (45^2/((3x10^8)^2))^0.5 simply isn’t enough.

Re: A delightful quirk of relativity theory

#95

Post by vidarh »

cjameskeller wrote: post #69
danbruc wrote: post #42

Earlier quoted context omitted.

Rescuing free-will from the jaws of spacetime would be cool! Free will does not exist. It is logically inconsistent. Either your choice is some function of your current state and the environment you are in, then the choice is not free, or it is independent of your current state and the environment you are in, then it is not your choice in any meaningful way, it is just the result of a coin flip. You can do some menta…

This is conflating causation and determination. It is true that one's choice must have a cause, and this can either be internal or external to oneself. But it is not true that the choice must be _determined_ by the cause. The Agent Causation [0] view denies the notion that only states or events can serve as causal priors, and instead asserts that substances themselves may be the terminal "cause" [0] https://plato.sta…

That just introduces infinite regress [1] into the mix. In order to justify why that would introduce free will you now need to justify why the substance itself has free will. It's not a solution.

[1] https://en.wikipedia.org/wiki/Infinite_regress

Re: A delightful quirk of relativity theory

#96

Post by snet0 »

bradstewart wrote: post #76
Thomashuet wrote: post #7

More readable formatting: https://threadreaderapp.com/thread/1482811504424542211.html

Am I crazy, in that I actually like Twitter threads for this sort of thing--at least in the hands of a capable author? When threaded correctly (as this one is), its easy to follow. And the requirement to condense and split thoughts into tweet-sized chunks creates natural breaks to pause and consider the content before continuing. I find the cadence of "each thought is a tweet" provides a nice rhythm. Sure, you can do…

I think this was one of the few good Twitter threads. Each Tweet was a kind of step from the previous, towards the next.

The only thing I think would be improved by having this in blogpost form is more interact-able visuals, equations and similar.

Re: A delightful quirk of relativity theory

#97

Post by whatshisface »

time_to_smile wrote: post #87
philipov wrote: post #83

Earlier quoted context omitted.

There is no room for free will in physics, period . All processes are completely deterministic. Even quantum processes might appear to be probabilistic if you look at individual particles, but the statistics are nevertheless completely deterministic: if you look at enough particles, a predictable shape will emerge. The future is set in stone and not only is there no way to change it, but the concept of changing the f…

You can even leave out the 'physics' part there. "Free will" is a very poorly defined concept that mostly falls out of problems with theodicy in early moral philosophy. Since the idea of "free will" plays a major role in Christian ethics this notion has permeated a huge amount of the Western intellectual tradition, but only makes sense in the framework of other archaic philosophical questions around theodicy like "if…

Free will might be hard to define but it has plenty of very well-defined corollaries. For example, if there is such a thing as free will, it would not be possible to reliably predict a human being's actions in advance.

Re: A delightful quirk of relativity theory

#98

Post by snet0 »

ramraj07 wrote: post #16
lordnacho wrote: post #2

Summary: For small angles, approximation makes it look like gradients (y/x) add simply (a+b). Similarly low velocity in relativity world makes it look like velocities just add as well. With some insight we discover how it really works, including how the approximation makes it look correct for small values.

But who was actually genuine surprised or flabbergasted that there was an extra factor that in macro real life becomes zero but is there in extreme speeds? The un-intuitiveness is typically more to do with understanding what that factor means and where it came from.

The insight is, in my opinion, more related to the attaching of the idea of "rotation" to space-time, and using that to explain why we can't just add velocities at high "rotations".

Re: A delightful quirk of relativity theory

#99

Post by logifail »

irthomasthomas wrote: post #21

This would be more fun in a blog post. Twitter is a fucking horrible format for a complex analysis of special relativity. That aside, my favourite quirk from relativity is this: "The more you move in space, the less you move in time." Like relativity in general, it sounds simple enough, but it's consequences are profoundly shocking. (That is, if you take the time to understand it, and don't leap to the conclusion tha…

> Twitter is a fucking horrible format for [..]

... any intelligent thought which takes more than a couple of sentences to type out?

Re: A delightful quirk of relativity theory

#100

Post by danbruc »

awb wrote: post #78
danbruc wrote: post #42

Earlier quoted context omitted.

Rescuing free-will from the jaws of spacetime would be cool! Free will does not exist. It is logically inconsistent. Either your choice is some function of your current state and the environment you are in, then the choice is not free, or it is independent of your current state and the environment you are in, then it is not your choice in any meaningful way, it is just the result of a coin flip. You can do some menta…

A few issues with the “free will” debate. 1) Define “free” 2) How do you test your hypothesis? You’re trying to apply logic to an untestable philosophical debate. If you believe free will doesn’t exist, you can’t design an experiment that would invalidate that belief. And if your theory is untestable and unfalsifiable, then what good is it other than a creative exercise? However, we do know from Quantum Mechanics tha…

However, we do know from Quantum Mechanics that the universe is probabilistic and not deterministic

That is not true, quantum mechanics - more specifically the Schrödinger equation - is deterministic. What is not deterministic is the wave function collapse but that is also incompatible with the Schrödinger equation because it implies non-unitary evolution of the wave function. And we have - as far as I know - no really good ideas how to resolve this. In consequence I think it would be premature to declare that the universe is definitively non-deterministic.

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