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A growing number of scientists are convinced the future influences the past

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Re: A growing number of scientists are convinced the future influences the past

#221

Post by nanidin »

dekhn wrote: post #179
nanidin wrote: post #140

Earlier quoted context omitted.

If we reverse time, would gravitational waves flow backwards?

yes. it's literally like playing a movie in reverse.

" it's literally like playing a movie in reverse" seems overly authoritative for something we haven't observed. I have seen Tenet, but it's a work of fiction.

Have we observed reflected gravitational waves? In reverse-time, where would they originate from if they presumably rippled out into space and didn't collide with anything in forward-time?

Re: A growing number of scientists are convinced the future influences the past

#222

Post by nanidin »

bigbacaloa wrote: post #178
entropicdrifter wrote: post #113

Earlier quoted context omitted.

Gravity is a universal constant. If you reverse time, you just reverse the order of cause and effect, not what the effect is . Does that make more sense to you?

"gravity is a universal constant" contradicts Newtonian mechanics, special and general relativity.

In these "it's like taking a video of throwing a ball in the air and allowing it to land on the ground, then playing it in reverse" examples, I can't help but think of Newton's first law. If an object at rest stays at rest, how does the ball leap from the ground? Where does the impulse come from? Reverse time seems too far fetched for me, or at least the simplified naïve version of it does.

Re: A growing number of scientists are convinced the future influences the past

#223

Post by richardw »

ChancyChance wrote: post #195

It's an article about QM. On Vice. About a QM thought experiment. On Vice. Why would there be any expectation of scientific rigor whatsoever? "retrocausality, may seem like science fiction grist at first glance" Stop there, vice.

https://en.wikipedia.org/wiki/Ad_hominem

Re: A growing number of scientists are convinced the future influences the past

#224

Post by klipt »

0xBABAD00C wrote: post #134
jonny_eh wrote: post #77

> It may seem eerie to our brains, which process events sequentially, but the history of science is also littered with examples of human biases leading to bad conclusions, such as the Earth-centric model of the solar system. Slow down. Assuming that time moves in one direction is not comparable to geocentrism.

Here's the analogy, per Sean Carroll [1]: - There seems to be a special direction "down", where things fall by default, because we live in the vicinity of an influential object in space, called Earth - There seems to be a special direction "forward in time", where things happen by default, because we live in the vicinity of an influential event in time, called Big Bang If we had stuck to the local Earth context and g…

Right, entropy can decrease, just with low probability, which you can calculate using the Fluctuation Theorem: https://en.wikipedia.org/wiki/Fluctuation_theorem

Perhaps given infinite time, we will randomly get back to a low entropy state infinite times, but I don't know enough about the math to say for sure.

Re: A growing number of scientists are convinced the future influences the past

#225

Post by marcus_holmes »

explaininjs wrote: post #91
marcus_holmes wrote: post #37

Interesting because it messes with the school of thought that everything is determined already and we're just following a sequence of actions that arise from the starting conditions of the universe. If causality is broken then maybe we have free will?

Scott Aaronson's "Ghost in the Quantum Turing Machine" tackled this question in a way I found enlightening. It's a bit of a dense read (I needed a plane trip to sit down and focus on it), but it presents a compelling case for the possible reversal of time arrows when it comes to the effects of quantum indeterminism on macro scale interactions. In short: what if humans, somehow, someway, have the ability to "influence…

That seems crazy - that my decision to have a ham sandwich for lunch had to be propagated all the way back to the start of the universe in order to happen ;)

And yes, provability is a major problem with all these kinds of theories. We don't have a parallel universe handy as a control, and just saying "I am not going to have a ham sandwich tomorrow" isn't a viable experiment.

Re: A growing number of scientists are convinced the future influences the past

#226

Post by agilob »

ChancyChance wrote: post #195

It's an article about QM. On Vice. About a QM thought experiment. On Vice. Why would there be any expectation of scientific rigor whatsoever? "retrocausality, may seem like science fiction grist at first glance" Stop there, vice.

Check other articles by the same author.

Re: A growing number of scientists are convinced the future influences the past

#227

Post by felipeerias »

prerok wrote: post #196
whatshisface wrote: post #114

Earlier quoted context omitted.

> Also, geocentrism is actually disproven by numerous observations, which in fact guided the mathematical formulation of our current physics. The validity of a coordinate system with the earth stationary at the center is guaranteed by the general principle of relativity. To get the stars to circle around it you would add a radially increasing potential in classical mechanics, or some coordinate shenanigans in GR. The…

To be honest, I have no idea what you are talking about. Certainly, there is merit in practical calculations when we are all this close to the ground where it all seems either flat or at least geo-centric. But... the movements of the other planets in our solar system were really strange to model in geo-centric models. In short, each of the other planets should rotate around an imaginary axis to compensate for their c…

In the XVII century, the alternative to heliocentrism was Tycho Brahe’s model: Earth at the centre, the Sun and Moon and the stars revolving around it, and the other planets revolving around the Sun. It was basically equivalent to the heliocentric model with a different coordinate system.

It’s important to understand that astronomers chose it because it really seemed to provide a better explanation given the knowledge and technology at the time.

Tycho Brahe himself noted that his model could be disproved by observing the stellar parallax effect as the Earth orbits the Sun (if the Earth does move, then the stars would look slightly different throughout the year). This is a real effect, but so small that it couldn’t be observed until the XIX century.

Re: A growing number of scientists are convinced the future influences the past

#228

Post by coldtea »

ChancyChance wrote: post #195

It's an article about QM. On Vice. About a QM thought experiment. On Vice. Why would there be any expectation of scientific rigor whatsoever? "retrocausality, may seem like science fiction grist at first glance" Stop there, vice.

Is there any point to the comment? Did Vice made the theory up?

Re: A growing number of scientists are convinced the future influences the past

#229

Post by marcus_holmes »

anotherman554 wrote: post #53
marcus_holmes wrote: post #37

Interesting because it messes with the school of thought that everything is determined already and we're just following a sequence of actions that arise from the starting conditions of the universe. If causality is broken then maybe we have free will?

It could just mean causality has more dimensions than we can perceive. It doesn't mean it is nonexistent.

So my decision to have a ham sandwich for lunch is determined by some meta-universe that created the starting conditions for this universe, and allows for the breach in causality? Or somehow is involved in the backwards-arrow of quantum events that the article talks about so the universe cannot turn out any other way?

I dunno, seems like a "God of the gaps" thing - we can speculate on meta-meta-universes endlessly. Including one where my decision to have a ham sandwich disturbs the state of a yet higher dimension that sets the starting parameters of your higher dimension and once again I have free will.

Re: A growing number of scientists are convinced the future influences the past

#230

Post by novaRom »

nextaccountic wrote: post #132
whatshisface wrote: post #118

Earlier quoted context omitted.

Let's check. F = ma F = m dv/dt u = -t dv/dt = -dv/du - F = m dv/du If you stop there it looks like you're right, but you also must change the definition of velocity to account for the new time. v = dx/dt = -dx/du +F = m dx/du So the direction of gravity (the force F) stays the same when you flip time. I can explain that without the math by pointing out that if you took a video of a ball being thrown up and caught an…

> I can explain that without the math by pointing out that if you took a video of a ball being thrown up and caught and played it in reverse, it would still depict a ball being thrown up and caught. That's amazing, thanks. The portion where you caught the ball in forward time is equivalent to throwing the ball in reverse time. I need to rewatch Tenet some day

I watched it 4 times. Only then I started to understand what's happening. How great and unique this movie really is.
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