Special Relativity negates free will

[ruffen]

In Special Relativity, space and time are relative.

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An important concept in Special Relativity is the fact that time progresses at different rates depending on relative velocity. So if I travel by you at great speed, you will see that my clock runs slower than yours, yet I will see that your clock is the one running slow.

What is even more interesting is the concept of relativity of simultaneity. This is a necessary consequence of Special Relativity.

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This means that viewed from a high-speed particle moving from the Sun towards the Earth, that particle's past contains parts of my future. So what I'll do tomorrow is in the past of certain reference frames, and not only hypothetical reference frames, but the reference frames of real particles out there.

This ultimately means that our 4D (3D space + 1D time) Universe is set like the 3D (2D space + 1D time) loaf of bread that Brian Greene slices at different angles depending on movement. This slicing is called the "hypersurface of simultaneity".

More info on that here:
Spacetime and the Relativity of Simultaneity


So all this means that our future already exists and is set. If someone moves towards us at high speed (and the larger their distance to Earth the better), then their "now" is in our "future". They cannot actually see our future because information can only travel at the speed of light, but their hypersurface of simultaneity still intersects with our future.

And if our future is already set, how can we have free will? Yes of course, we choose our actions, but what we will actually choose in the future is already set just as much as what we chose in the past is set.

 

[Amechania]

How would you suggest a person approach life based on this perspective? I can't see how it would make much difference to someone trying to make decisions except to alleviate some of the regret of bad calls. I've already resigned myself to fate anyhow.

 

[ruffen]

It doesn't mean that one should resign and stop making useful decisions. In practice, it means very little.

For example, if the future holds that something bad will happen, one might think that it is useless to do anything to prevent bad stuff from happening, but then again, maybe the future brings the fact that your effort is what prevented bad stuff from happening.

So the decision is still yours, it's just that what choice you will make, is already determined. This is coherent with deterministic world views, where you still get to make a choice, but a neuroscientist with probes in the right places in your brain will be able to predict what you choose before you know it yourself.

It will never be practically usable for predicting the future, because you have to be far away and move fast toward Earth for your hypersurface of the present to look a useful amount of time into the Earth's future, and you will not be able to see it because that information on Earth's future will have to travel at light speed and will therefore not reach you in time for you to warn us of future events. Thus causality is preserved.

So this is in a way just a theoretical construct with no practical applications, but nonetheless real if Special Relativity is real (and it is, and it has been tested thoroughly and is among other things tested in every GPS receiver every day, as relativistic effects must be accounted for if GPS is to be accurate).

But what this tells us is that my present can be your future or past depending on our motion relative to each other. It therefore also tells us that the past and the future are every bit as real as the present. This has philosophical consequences, but I do not think it has any practical consequences.

The illusion of free will is still important - you still have to eat and drink and go to the toilet and plan for the future and do the right decisions, it's just that those decisions are already determined, and that fact seems to strengthen the deterministic view of the Universe.

Cause and effect and any sequence of events is just a static "shape" or "blob" in the 4D spacetime. This also means that the randomness introduced by Quantum Mechanics is highly overrated. Because the future is already set, this means that the future discovery of whether Schödinger's Cat is dead or alive, already exists. Which would again imply that the randomness and probability distributions seen in Quantum Mechanics is just due to unseen underlying mechanisms. If it is truly probabilistic and random in nature, and yet the outcome is determined by some particle moving fast toward us, is it then truly probabilistic? I'm talking about for example the probabilistic nature of proton decay - because the future answer on exactly when that exact proton will decay, is already set. The wave distribution of the position of an electron, for example, is more difficult, because the proton is at a given time partly at many places simultaneously.

But any event that seems probabilistic with respect to what will happen or exactly when it will happen, is already determined, it would seem.

 

[Amechania]

Brain...pain...nose...blood. It really just seems to be a matter of perspective. Could a being within the universe experiences the reality of chance and the illusion of predetermination, whereas a being outside the universe or on the extreme edges of spacetime experience the opposite: a seeming reality of inevitability and an intuition of chance?

 

[idav]

I dont think special relativity negates free will, if anything it makes it possible since things aren't all linear like we prefer, like eisntein would have preferred even.

 

[Willamena]

So all this means that our future already exists and is set.

No... because "time is relative," and we are examing events relatively. When one person sees the other's clock as slower, we have to change frame to see the other person see their clock is normal and the first person's clock is not. We can only examine events from one frame or fixed point at a time.

 

[idav]

No... because "time is relative," and we are examing events relatively. When one person sees the other's clock as slower, we have to change frame to see the other person see their clock is normal and the first person's clock is not. We can only examine events from one frame or fixed point at a time.

Eventually the fixed points can merge. I could have a kid, go traveling the speed of light for 30 years and come back to an earth where my kid is my age.

 

[Willamena]

Eventually the fixed points can merge. I could have a kid, go traveling the speed of light for 30 years and come back to an earth where my kid is my age.

How have "fixed points merged" in your story? It seems to be narrated from one point of view.

 

[idav]

How have "fixed points merged" in your story? It seems to be narrated from one point of view.

Both views have velocity, but only one has the speed to make a difference. After experimenting with velocity they find that clocks dont stay in sync when one of the clocks was going at high speeds. You do have a point about the observer, seems like I am throwing in a third observer to observe the relativity of two objects in question.

 

[Willamena]

Both views have velocity, but only one has the speed to make a difference. After experimenting with velocity they find that clocks dont stay in sync when one of the clocks was going at high speeds. You do have a point about the observer, seems like I am throwing in a third observer to observe the relativity of two objects in question.

Right. Both clocks remained in the present at all times.

Edit: Or, if it makes more sense, think of it as that there is no present, just bendy wiggly-wobbly spacetime.\
(I love that science eventually caught up with Doctor Who.)

 

[idav]

Right. Both clocks remained in the present at all times.

Edit: Or, if it makes more sense, think of it as that there is no present, just bendy wiggly-wobbly spacetime.

Sure they remain in present but the clocks will not be in sync when one of them slows down due to speed.

Yeah bendy wiggly wobbly spacetime , that will work.

On perspective both objects would appear to speed up based on the speed of the observer. Same thing with a black hole, time slowz down as we approach a black hole and outside the black hole everything would appear to speed up. Though in a black hole is due to gravitational time dilation.

 

[Willamena]

It's never the case that one clock is in the future, though, as I understand the problem. That may properly be labelled "illusion" from the relevant frame of reference, and illusion created by the idea that spacetime is like a flat surface and we are all supposed to be riding along on a similar plane.

(But maybe I misunderstand the problem.)

 

[idav]

It's never the case that one clock is in the future, though, as I understand the problem. That may properly be labelled "illusion" from the relevant frame of reference, and illusion created by the idea that spacetime is like a flat surface and we are all supposed to be riding along on a similar plane.

(But maybe I misunderstand the problem.)

It is real because we already have machines that need to take time dilation into account.

Time dilation - Wikipedia, the free encyclopedia