Time

Originally posted by apathist
Not just that. Science is [b]unable to address many of our questions. Logic and reason are tools and nothing more. Every tool has a job, and can be misused. Beware of scientism, humy.[/b]

Not just that. Science is unable to address many of our questions.

If science, i.e. if the theorizing based purely on the imperial evidence and/or flawless logic alone, cannot answer those questions, then, except for questions of either morality or taste, they are stupid questions by being unanswerable questions and not worth asking. For example, the question of what is the meaning of life and the universe and anything else? Since nobody can define the meaning of the question, it is a stupid unanswerable question. If, as you say, "Science is unable to address many of our questions", all that means is that, excluding those that are purely morality or about good/bad taste, those questions are stupid unanswerable ones.

Logic and reason are tools and nothing more.

and they are the only tools we have for valid inference of what the truth might be. They are also generally quite effective tools at that so that "and nothing more" comment is pretty idiotic. Do you reject logic and reason? If so, why?

Every tool has a job, and can be misused.

no, flawless logic can never be misused to assign probabilities to theories else it wouldn't be flawless logic.

Beware of scientism, humy.

Since the word "scientism" has several different mutually exclusive meanings, typically with pretty vague subtle differences between them at that, that is a meaningless statement without defining concisely exactly what you mean by "scientism".

Originally posted by apathist
I don't know if your numbers are right, but your concept is. You understand the traveler got only one regular lifetime?

His own fundamental time clock is slowed down so he thinks he sees one second go by on his clock but 7 seconds has gone by on Earth. The formula is pretty simple, T =Sqr root of 1 minus V^2/c^2 which says at 99% of c time goes by about 7 times slower so you go to a start 70 light years away and you on board aged only 10 years. So you stay at the target star say 10 years and go back at the same velocity, you age 30 years but when you get back 150 years passed on Earth so you are in fact being injected into your own future and nobody you knew including their grandchildren and greatgrandchildren are most likely dead. You are a real live Rip Van Winkle totally now out of touch with Earth, having to learn everything all over again, since in 150 years, political systems come and go, maybe the USA is gone, maybe English has evolved where you will not even be understood. You will be a duck out of water.

Originally posted by humy

Not just that. Science is unable to address many of our questions.

If science, i.e. if the theorizing based purely on the imperial evidence and/or flawless logic alone, cannot answer those questions, then, except for questions of either morality or taste, they are stupid questions by being unanswerable questions and not worth asking. For ...[text shortened]... that is a meaningless statement without defining concisely exactly what you mean by "scientism".

I wonder what "Imperial Evidence" is? The rest of your post seems to revolve around the idea that a question that cannot be answered on the basis of empirical evidence has no meaning. This sounds like logical positivism, the basic tenet of which is a sentence along the lines of: "Any statement which is not empirically verifiable has no meaning.". The difficulty is that that sentence is not empirically verifiable. Consequently the basic tenet of logical positivism has no meaning within the terms of reference of logical positivism.

Now, you might attempt to rescue logical positivism by arguing that one could enumerate all sentences and see which ones are meaningful to test the basic tenet of logical positivism. Finding a sentence which is meaningful but not verifiable would then disprove logical positivism and not finding one would prove it. The problem there is that one needs a separate definition of what sentences are meaningful. Given that definition one may as well ditch the tenet I showed above. So there is no way around it, logical positivism is bunk.

Originally posted by DeepThought
I wonder what "Imperial Evidence" is? The rest of your post seems to revolve around the idea that a question that cannot be answered on the basis of empirical evidence has no meaning. This sounds like logical positivism, the basic tenet of which is a sentence along the lines of: "Any statement which is not empirically verifiable has no meaning.". The ...[text shortened]... well ditch the tenet I showed above. So there is no way around it, logical positivism is bunk.

I wonder what "Imperial Evidence" is?

oh that was a msiedit. That should have been "empirical evidence".
I have absolutely no idea what "imperial evidence" is.

The rest of your post seems to revolve around the idea that a question that cannot be answered on the basis of empirical evidence has no meaning.

oh no, that wasn't what I was saying. I would say they could still 'mean' something, even if they are unanswerable or even stupid questions.

Not yet sure because haven't yet got to study it properly but, from my little current knowledge of logical positivism, I currently think I would probably come to disagree with it. But I have to wait to later in my current research to when I came to study logical positivism in relation to my research before deciding whether logical positivism is valid and then say whether it is valid and why so in my book.

Originally posted by DeepThought
Your perception of time is due to chemical rates and signal path duration as neurones fire signals at one another. That there is an arrow of time is to do with entropy rather than anything particularly fundamental to the dimension itself. Entropy always increases and has a maximum, when all micro-canonical states are equally probable, in that situation ...[text shortened]... ent thing from time somehow ceasing to exist, which would involve the universe ceasing to exist.

I don't have a problem with calling time a dimension because of its relationship with space. But I think it's possible to illustrate a fundamental difference between the 3 dimensions of space and the 1 dimension of time with a simple thought experiment:

If I remove the dimension of time, could the remaining 3 dimensions of space continue to exist? Intuitively the answer appears to be 'yes'. However (and I'm probably mistaken) you seem to be saying 'no' due to entropy... (?)

So my next question is, if you remove any one of the 3 dimensions of space could the remaining 3 dimensions (2 of space plus 1 of time) continue to exist? Again (intuitively) my answer would have to be 'no'. To illustrate, if you take a wooden board (having width length and depth) and completely shave away any one of its dimensions, the entire board will be gone (cease to exist). And time (as a dimension) would also cease to exist, because the existence of time is dependent on the other 3 dimensions.

Originally posted by lemon lime
I don't have a problem with calling time a dimension because of its relationship with space. But I think it's possible to illustrate a fundamental difference between the 3 dimensions of space and the 1 dimension of time with a simple thought experiment:

If I remove the dimension of time, could the remaining 3 dimensions of space continue to exist? Intu ...[text shortened]... would also cease to exist, because the existence of time is dependent on the other 3 dimensions.

Not sure where you went from point A to point B. If you have a 3 D universe and take away time, you would still have 3 dimensional objects but they would be forever static, not able to change position. They would still be 3 D but more like a holographic photo.

Originally posted by sonhouse
Not sure where you went from point A to point B. If you have a 3 D universe and take away time, you would still have 3 dimensional objects but they would be forever static, not able to change position. They would still be 3 D but more like a holographic photo.

it would be impossible to observe anything in such a 'time-absent' universe or for consciousness to exist in such a universe, and it is impossible for us to truly imagine space with no time since we always takes periods of time for us to imagine, but that's another matter and just because we cannot imagine something doesn't mean it cannot be so and a reminder of that fact is that we cannot visualize the vast number of particles there must exist in the known universe and yet that number of them must surely exist.
I have often noticed there is a common implicit erroneous assumption many people make of intuitively assuming if they cannot imagine it then it cannot be.
Just because we cannot imagine space without time or time without space doesn't logically entail one cannot exist without the other.

Originally posted by sonhouse
Not sure where you went from point A to point B. If you have a 3 D universe and take away time, you would still have 3 dimensional objects but they would be forever static, not able to change position. They would still be 3 D but more like a holographic photo.

Not sure what points A and B are, but so far we are in agreement. I said "thought experiment", but there were actually two of them and we seem to be in agreement with the first one.

I see time and space as being both intangible and real. Both exist (are real), but neither are (in and of themselves) a tangible material reality. Space can exist without (is not dependent on the existence of) time, but time cannot exist without space. And the existence of space is dependent on the presence of a physically material 3D reality. Without anything else to define what space is (or might be) it would only exist as 'nothing' or 'nothingness'. But space is not nothing... it came into existence when time and gravity and everything else began to exist.

Originally posted by lemon lime
Space can exist without (is not dependent on the existence of) time,

how do you know this?

but time cannot exist without space.

how do you know this?

Originally posted by humy
how do you know this?

but time cannot exist without space.

how do you know this?

Time cannot be static, and it would have to exist before it could be measured. But how would you define time 'flow' without the medium of space? If only one thing existed, say a single material point, then how (or in what form) would time exist?

A single material point could (theoretically) exist without space, but I don't see how time flow could exist without there being a number of material points/objects separated by space. Without space to move around in nothing changes because nothing can change...

Is there such a thing as 'static' time, or motionless time flow?

Originally posted by lemon lime
Time cannot be static, and it would have to exist before it could be measured. But how would you define time 'flow' without the medium of space? If only one thing existed, say a single material point, then how (or in what form) would time exist?

A single material point could (theoretically) exist without space, but I don't see how time flow could exis ...[text shortened]... ecause nothing can change...

Is there such a thing as 'static' time, or motionless time flow?

Time cannot be static

You mean time moves? In what sense? You must be confusing the concept of the dimension of time with the point along that dimension we call the present.

But how would you define time 'flow' without the medium of space?

Why not? Why cannot there be a universe with time but no space and time 'flow' in an unobservable way we cannot imagine nor visualize? Are you making the assumption that just because we cannot imagine or visualize or understand it, it cannot be so?

A single material point could (theoretically) exist without space, but I don't see how time flow could exist without there being a number of material points/objects separated by space. Without space to move around in nothing changes because nothing can change...

Now you are again confusing the concept of change with time. They are not the same thing. Change is something that happens IN time, not what IS time.

Also, by stating that "but I don't see how", I can see you are making the logical error many people make which I explained in my other post; you are erroneously assuming that, just because you cannot imagine or visualize something, it cannot be so.
Proof of that is that you cannot visualize the vast number of particles there must exist in the known universe and yet you surely believe that number of them must surely exist.

remember, I did say;
"I have often noticed there is a common implicit erroneous assumption many people make of intuitively assuming if they cannot imagine it then it cannot be.
Just because we cannot imagine space without time or time without space doesn't logically entail one cannot exist without the other."

Originally posted by lemon lime
Time cannot be static, and it would have to exist before it could be measured. But how would you define time 'flow' without the medium of space? If only one thing existed, say a single material point, then how (or in what form) would time exist?

A single material point could (theoretically) exist without space, but I don't see how time flow could exis ...[text shortened]... ecause nothing can change...

Is there such a thing as 'static' time, or motionless time flow?

In a one dimensional space there is nothing to distinguish a time-like and space-like dimension. What makes time time in General relativity is the way it transforms. So if you rotate your axes, in the ordinary sense, then the transformation involves trigonometry. If you introduce a boost then the coordinate system changes by a hyperbolic rotation, so rather than cos and sin you need to use cosh and sinh. Sorry, off hand I can't think of a non-technical way of explaining this.

Originally posted by DeepThought
. Sorry, off hand I can't think of a non-technical way of explaining this.

I suspect that's because there is none. The 'best' we can do to explain the subtleties of physics to laypeople without tediously explaining the whole thing properly is use counterproductive analogous that inevitably do far more to make them misunderstand than understand and, to make matters worse, make them think they understand. The classic example of that is the trampoline analogy to explain gravity; it is impossible to visualize a trampoline without 3D space being above and below the trampoline thus inevitably making many laypeople think that means there is space above and below the curvature of 3D space, which is a big misunderstanding.

Originally posted by DeepThought
In a one dimensional space there is nothing to distinguish a time-like and space-like dimension. What makes time time in General relativity is the way it transforms. So if you rotate your axes, in the ordinary sense, then the transformation involves trigonometry. If you introduce a boost then the coordinate system changes by a hyperbolic rotation, so ...[text shortened]... to use cosh and sinh. Sorry, off hand I can't think of a non-technical way of explaining this.

By boost, I assume you mean acceleration?

Originally posted by sonhouse
By boost, I assume you mean acceleration?

Sort of, given two observers moving relative to one another then to get between their coordinate systems one needs a boost. This isn't an acceleration, in the sense that nothing material is being accelerated, but is like an acceleration in the sense that there's a change in velocity. The technical term is boost to avoid the confusion involved in calling it an acceleration, which would be huge as there are also accelerated frames of reference, such as the one I'm sat in now as I type this.