# How would you know? Thought experiment

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If you are in empty space, nothing around. Just a waste space of nothingness. You could be traveling at the speed of light, casue you don't have anything relative to you. How would you know?

If 1000 people without the knowledge of time or clocks ended up on, say a space station without anything relative to them, how would time look like to them? How would time evolve?

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If you are in empty space, nothing around. Just a waste space of nothingness. You could be traveling at the speed of light, casue you don't have anything relative to you. How would you know?

Well, you couldn't be travelling at the speed of light (because nothing with mass can). But as speed can only be defined relative to something else then, if there is nothing else, then you must be stationary by definition.

If 1000 people without the knowledge of time or clocks ended up on, say a space station without anything relative to them, how would time look like to them? How would time evolve?

Time would "evolve" (pass, whatever) in exactly the same way whether they know about clocks or not. If they don't have clocks they can't measure it. But time passed long before people had clocks (or long before people).

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Well, yes. Time will always have a direction from say a to b. But How would the time evolve in terms of how to measure it. Since there is no night and day, no moons. Would it be like how many steps you use from one end of the station to the other? ''Hey, lets meet up in 200 steps'' They will not know about seconds or hours. So the question is: How to make a device to measure time when you don't have anything to relate to? And what units would be the most logic to use?

And I agree about the speed part:)

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Well, yes. Time will always have a direction from say a to b. But How would the time evolve in terms of how to measure it. Since there is no night and day, no moons. Would it be like how many steps you use from one end of the station to the other? ''Hey, lets meet up in 200 steps'' They will not know about seconds or hours. So the question is: How to make a device to measure time when you don't have anything to relate to? And what units would be the most logic to use?

Heartbeats. Dripping water. Slow burning candles. Look at the history of clocks.

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Well, yes. Time will always have a direction from say a to b. But How would the time evolve in terms of how to measure it. Since there is no night and day, no moons. Would it be like how many steps you use from one end of the station to the other? ''Hey, lets meet up in 200 steps'' They will not know about seconds or hours. So the question is: How to make a device to measure time when you don't have anything to relate to? And what units would be the most logic to use?

And I agree about the speed part:)

This is false, atomic (cesium or rubidium) clocks do not need any reference, they ARE the reference.

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And what units would be the most logic to use?

The choice is completely arbitrary. The most "logical" is whatever is practical and useful.

Edited by Strange
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If you are in empty space, nothing around. Just a waste space of nothingness. You could be traveling at the speed of light, casue you don't have anything relative to you. How would you know?

If 1000 people without the knowledge of time or clocks ended up on, say a space station without anything relative to them, how would time look like to them? How would time evolve?

Do you at least understand that "speed" has to be measured relative to something? Your first question is simply meaningless.

As for your second question, there are still things such as heartbeat, breathing rate, etc. that give a rough measure of time.

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Do you at least understand that "speed" has to be measured relative to something? Your first question is simply meaningless.

As for your second question, there are still things such as heartbeat, breathing rate, etc. that give a rough measure of time.

well, speed is relative. And the question is not meaningless. It was a question that was asked a long time ago. And it was a question that had to be asked, or we would not be where we are today. Its all about the philosophy of physics.

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It was a question that was asked a long time ago.

Asking what speed is with no reference is meaningless.

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well, speed is relative. And the question is not meaningless. It was a question that was asked a long time ago. And it was a question that had to be asked, or we would not be where we are today. Its all about the philosophy of physics.

But you posted this in physics, not philosophy. The physics answer is that everyone in an inertial frame of reference can consider themselves to be at rest. There's no way to distinguish whether you are moving or at rest.

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In the absence of anything, I suppose the most rudimentary clock is ones own internal body rhythm; rest time and active time

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Time > is not relevant... if matter do not exist.

Time is only an illusion of the mind,,,only the senses can decide of time .

From the expected result; I would be satisfied.

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Time > is not relevant... if matter do not exist.

Time is only an illusion of the mind,,,only the senses can decide of time .

From the expected result; I would be satisfied.

Two things can't be in the same place at the same time but they can at different times, so time exists independent of mind.

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Time > is not relevant... if matter do not exist.

Time is only an illusion of the mind,,,only the senses can decide of time .

If time is only an illusion of the mind, how did the universe develop before minds existed?

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If time is only an illusion of the mind, how did the universe develop before minds existed?

Who says it 'developed'?

You see the universe 'developing' but that's only an illusion of the mind.

Einstein: the distinction beween past, present and future is only an stubornly persistent illusion.

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Who says it 'developed'?

You see the universe 'developing' but that's only an illusion of the mind.

Einstein: the distinction beween past, present and future is only an stubornly persistent illusion.

You are quoting an extract from a personal letter he wrote to the wife of his recently deceased close friend Michele Besso. My guess is he was saying something totally different to what you think it means and its meaning is a personal one meant as consoling words, not a a scientific one.

Besso was born in Riesbach of Jewish Italian (Sephardi) descent. He was a close friend of Albert Einstein during his years at the Federal Polytechnic Institute in Zurich,[2] today the ETH Zurich, and then at the patent office in Bern, where Einstein helped him to get a job.[3] Besso is credited with introducing Einstein to the works of Ernst Mach, the sceptical critic of physics who influenced Einstein's approach to the discipline.[4] Einstein called Besso "the best sounding board in Europe" for scientific ideas.[5]

Besso died in Geneva, aged 81. In a letter of condolence to the Besso family, Albert Einstein included his now famous quote "Now he has departed from this strange world a little ahead of me. That means nothing. People like us, who believe in physics, know that the distinction between past, present and future is only a stubbornly persistent illusion." Einstein died one month and 3 days after his friend, on 18 April 1955.
Edited by StringJunky
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You are quoting an extract from a personal letter he wrote to the wife of his recently deceased close friend Michele Besso. My guess is he was saying something totally different to what you think it means and its meaning is a personal one meant as consoling words, not a a scientific one.

That's indeed your personal guess.

I know what Einstein wrote:

<< Since there exists in this four dimensional structure [space-time] no longer any sections which represent "now" objectively, the concepts of happening and becoming are indeed not completely suspended, but yet complicated. It appears therefore more natural to think of physical reality as a four dimensional existence, instead of, as hitherto, the evolution of a three dimensional existence. >> (Albert Einstein, "Relativity", 1952).

<< From a "happening" in three-dimensional space, physics becomes, as it were, an "existence" in the four-dimensional "world". >> (Albert Einstein. "Relativity: The Special and the General Theory." 1916. Appendix II Minkowski's Four-Dimensional Space ("World") (supplementary to section 17 - last section of part 1 - Minkowski's Four-Dimensional Space).

<<...for us convinced physicists the distinction between past, present, and future is only an illusion, although a persistent one." >> ( Letter to Michele Besso family, March 21, 1955. Einstein Archives 7-245).

In case you doubt;

Karl Popper about his encounter with Einstein:

<< The main topic of our conversation was indeterminism. I tried to persuade him to give up his determinism, which amounted to the view that the world was a four-dimensional Parmenidean block universe in which change was a human illusion, or very nearly so. He agreed that this had been his view, and while discussing it I called him "Parmenides".... >> (Karl Popper, Unended Quest: An Intellectual Autobiography.Routledge Classics. Routledge. pp.148–150).

And Einstein believed in physics when he said his famous quote:

<<People like us, who believe in physics, know that the distinction between past, present and future is only a stubbornly persistent illusion." Einstein died one month and 3 days after his friend, on 18 April 1955.>>

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

Edited by VandD
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!

Moderator Note

Let's all remember this thread is in Relativity, not Philosophy. If you have philosophical aspects to discuss, they would be best explored in a different thread.

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