[another_someone]

quote:Originally posted by Roy P
Is time infinitely divisible? If so, a stationary vehicle just about to accelerate forward will never attain a forward movement.

The whole discipline of calculus is based upon an infinite number of infinitely divided segments creating a finite answer.

George

[ukmicky]

quote:Originally posted by neilep


Is that akin to why can I never clap my hands ?...cos I start off a foot apart, then 6 inches then 3 then 1.5...etc etc ad infinitum !!...so how can I clap my hands then , If my hands are always going half the next distance ?

NO COMMENT[]



 

quote:How about this program about time folks http://www.bbc.co.uk/bbcfour/documentaries/features/time.shtml I hope it makes it over to mainstream BBC too

I saw the series a while back, it was ok, not to heavy and quite enjoyable.

Michael

[Laith]

I can hit the submit button to put this post, or I can just close the page and discard the post, I can choose to drink tea or drink coffee, isn’t that free will?
if we live in a 4d universe, would that mean that I already thought about having tea or coffee and chose tea for example and I’m just reliving it now??
How do you define free will?


Laith

[dynamix]

quote:Originally posted by neilep

Good post Roy ...it's well heavy for me !

Is that akin to why can I never clap my hands ?...cos I start off a foot apart, then 6 inches then 3 then 1.5...etc etc ad infinitum !!...so how can I clap my hands then , If my hands are always going half the next distance ?

There are a few of these little "paradoxes", based on the infinite division model supplied by calculus-based mathematics. Another one is that you can, supposedly, never close a door, for ostensibly the same reason.

Here is a "different" way of looking at the problem, based on that eternally open door. (You can apply it to other examples, but the door-closing one is easier to describe and understand - somewhat less abstract!)

I submit, IMO, that the problems arise due to an inaccuracy of language, rather than a failure of Physics or Mathematics. In other words, what do we mean by the term "the door is closed"?

The ordinary lay-person's definition is regulated solely by the necessity of having "the wood in the hole". They are describing a situation where the elements, thieves, strangers, even family members in the next room, etc. are kept out, and they are thus "inside" (another ambiguous term!) and protected. The scientific definition, however, would require that the door & jam were completely joined at the molecular level, which, of course, given the fact that they were probably manufactured from several different pieces of wood (even if they weren't, you would need the sawdust from the original cut, and an absence of Chaos Theory!), is physically, and therefore scientifically, impossible. Hence, on that basis, the Calculus model is correct, and we can never close that blinkin' door! The same logic extends to your hand-clap. Even when you clap REALLY loud, at the point of contact there will still be a microscopic air-gap between your hands. If there was not, your hands would be joined at the molecular level, and you would probably be typing with your toes... unless you apply the same logic to the process of touching your toe to the keyboard! []

So you see, there is no real discrepancy, merely an ambiguity of language. If you allow for the ever-present air-gap, however small it may be, the number of steps to door-closure, hand-clapping, etc, becomes finite, and the problem is solved!

And for my next trick... []

"What's a unified theory, daddy?"...
"Ask your mother!"

[another_someone]

quote:Originally posted by Laith
I can hit the submit button to put this post, or I can just close the page and discard the post, I can choose to drink tea or drink coffee, isn’t that free will?
if we live in a 4d universe, would that mean that I already thought about having tea or coffee and chose tea for example and I’m just reliving it now??
How do you define free will?

If we live in a 4D universe, where time is already predetermined, then thought is merely an illusion.

Thought is the process where by a contents of your mind change over time.  If time is an illusion, then the contents of your mind is already predetermined, it is merely your awareness of that contents that is different (i.e. 10 minutes ago the mind that existed in that environment did not yet contain the memories that it has 10 minutes later, but those memories already existed in the 4D extrapolation of your mind, an extrapolation that would no more see those memories as accumulating over time as it might see them dissipate in forgetfulness if time were to move in the opposite direction).

George

[yor_on]

This one was actually more brain feeding than most of the links I've seen recently.

So?

What do you think.

Is God one of those nerdy guys with big glasses, running around mumbling untellable things?

Was he mobbed at school?

---
Sorry missed that I had wrote 'unintelligent' when meaning 'untellable'. There is a difference you know. I'll blame it on me using 'software' when I couldn't remember the correct spelling. I will punish it (the software:) They won't succeed taking over my world at least.

Wha...@€£{[ !!!! Dieeee. . .

[yor_on]

---Originally posted by Laith---
Time consists of:
Past Time - which no longer exists
Future Time - does not yet exist
Present time - takes no time at all
-------------------------------------------


What exists is dependent upon that which we perceive to exist.  We cannot know of any absolute existence, only of our perception of existence.

The past exists because we perceive of its existence (i.e. we remember it existing).  In fact, it is the present that cannot exist, because we cannot know of anything until some small fraction of a second after it has happened.

Ofcourse, there are degrees of past, some closer than others.

Well reading you I think that time do exist even though we are pretty bad 'eyewitnesses' as you state. Life is all about times arrow, if we stop trusting in it makes no difference. it will still move us 'forward'.

As for 'past', 'present' and the 'future' I agree on that the 'present' alway will be an 'after construction' made after the facts. So in a way no biological system can be 'there'. Not while obeying physical processes.

But we have this strange idea about consciousness and meditation. when you stop your 'thinking' sort of, it seems that this is a state needed for 'enlightenment', although there might be other ways too?

Why I drag it up is because consciousness is a little like those smallest constituents in physics, nowhere to be found, no matter how good we will become on seeing its effects and the predispositions craved for it to exist. Maybe I'm wrong but I expect consciousness to be very like those constituents? There but not 'there' at all.

As for the future it can only be said to exist as long as we don't know it. If we by some fluke, would be able to know it, predetermination would have won and we would no longer have that 'free will', as I see it that is. To me you can't have both a knowledge of 'all things to come' and your free will. Not as long as we are talking about only one SpaceTime at least.

This is a very interesting thread to me in fact

[Ethos]

Regarding this issue of time:

It's common to hear comments about the past, the present, and the future. I'd like to stir the pot just a tad by offering the following thought experiment.

The concept of, "the past" is comfortable for us because we talk about history and how it has influenced "the present". We construct plans regarding "the future" to insure that our common goals are met. Now, I'd like to think for a moment about "the present". The moment we speak about "the present", it's already become "the past".

"The past" lies 13.7 billion years behind us, according to cosmologists, and "the future" lies a possible infinity before us. Where does that leave "the present"? I submit that there is no such thing as "the present". Only "the past and the future".

[questioner]

Aren't we all time travelers the past is our memories, our present is as we perceive it and the future is in our imagination.

[yor_on]

Nicely put.

Almost poetic in fact.

[LeeE]

Yup, this is one of the more interesting old threads to resurrect.

The question, as posed in the thread title, cannot be answered definitively, although I think it's fair to say we've got quite a lot of insight relating to it.

First of all, we can show that clear relationships exist between space and time, hence the emergence of the concept of a unified space-time.  However, while we these relationships indicate that space and time are essentially the same, our personal perspective indicates that they are fundamentally different, and I think this is where and why the entire issue arises.

The most obvious difference seems to be that we can move in any direction through space but can only move forward through time.

One way that this can be explained is to look at the phenomenon of time dilation due to spatial movement i.e. the way that time appears to slow down as one moves faster.  Now the Lorentz solution that describes time dilation due to spatial movement is a simple adaptation of Pythagoras's right-angle triangle solution, where Lorentz uses it to sum the movement vectors through space and time.  The solution indicates that the sum of the two vectors is always equal to the speed of light 'c', so that the rate of movement through time reduces as the rate of movement through space increases, and visa-versa (when you normalise the rates of movement along both axis to the range 0 - 1 and then plot the curve you end up with a quadrant of a circle  []).

It also seems that, in accordance with Relativity, it is not possible for anything with a non-zero rest mass to be accelerated to 'c'.

The consequence of this is that anything with non-zero rest mass must always exist on the circular arc between the two axis but can never actually reach either axis and just as nothing can be accelerated to 'c', so that the rate of movement along the time axis reaches zero, the implication is that the same holds true at the other end of the arc and nothing can ever be absolutely stationary and move at the temporal equivalent of 'c' through time.

In short then, to change our direction in time would need us to cross the axis, which we can't because we can only ever approach it.

Just going back to that circular plot is also instructive; we seem to only exist along that arc in the quadrant between the two +ve value axis, but the implication of a complete circle is clear.

Also consider how what we view as three spatial dimensions and one temporal dimension may well be transformed into, let's say two spatial axis and two temporal axis.

Imagine a cylinder: we perceive it as a three spatial-dimensional object that exists in a single temporal dimension but we could just as easily define it as being a two dimensional disk that exists for a period of time where the length of the cylinder represents its temporal duration i.e. its life time, but because it has two temporal dimensions we can see its entire life time all at once instead of serially.

So no definitive answer, but I don't think we're entirely devoid of ideas and insights.

[yor_on]

Weirdly nice LeeE
That one take some time assimilating.

I've seen you present that idea before but here you made it clearer to me. I will reread it when I slept.

[yor_on]

"Just going back to that circular plot is also instructive; we seem to only exist along that arc in the quadrant between the two +ve value axis, but the implication of a complete circle is clear."

So, do you have any diagram showing this possible circle?
With some examples of how you see that it could be used, ordinary and more 'imaginative' like your example with the cylinder?

(Well I slept a little so I should be able to understand something?

[Make it Lady]

If time is an illusion, how comes David Copperfield, Paul Daniels or David Blain never use it as part of their act?

I find it interesting that we have no linear time memories before the age of about 4 years old so the perception of time is obviously a learnt thing.

[LeeE]

"Just going back to that circular plot is also instructive; we seem to only exist along that arc in the quadrant between the two +ve value axis, but the implication of a complete circle is clear."

So, do you have any diagram showing this possible circle?
With some examples of how you see that it could be used, ordinary and more 'imaginative' like your example with the cylinder?

(Well I slept a little so I should be able to understand something?

Heh - I've been meaning to make a diagram to explain it more easily as the time dilation thing comes up quite often - just haven't got around to it yet.  In short though, you just need to extend the axis to cover both +ve and -ve ranges to see where the full circular plot is implied.

However, although the implication of a full circle is there, I'm not sure that it means anything because what we're talking about here is spatial speed, which is directionless, so negative values of speed don't really make much sense.

Then on top of that, you have the problem of trying to find the square root of negative numbers when you're working in the adjacent quadrants.

[yor_on]

We won't know LeeE but it sure fires the imagination, and from there might a experiment come

"I find it interesting that we have no linear time memories before the age of about 4 years old so the perception of time is obviously a learnt thing."

Well, can't that be due to the time our brain needs to make all the synapses fire in the right order to place it in our 'long time storage'?

[yor_on]

You see, there is this experiment involving gravity and babies.

you have a screen, two magnets, on behind and one before the screen f ex. connected...

And then you film the babies eye movements.

You will find that if you change the magnets trajectory from following a 'normal' path of gravity to one 'impossible' for following gravity that the baby's eye movement still will track the path it should have followed.

If it didn't have any feeling for 'times arrow', that is ordered sequences in time, then that shouldn't happen.

[Make it Lady]

Wow, that's interesting. Put that aside and personally try to order events in your past. You can do it down to just before you start school. Before that events seem to be on a confused plain with no order. Maybe it has more to do with how our brains process memories but I feel that to a certain extent appreciation of time passing is a learnt thing.
If you do an activity that puts you in the zone time seems to pass faster than if you are bored or waiting for a train. Your appreciation of time can be altered in this way. 

[LeeE]

Here's an attempt at a diagram:



This shows the relationship arc (in pink) between spatial speed and time dilation.  The red plot shows how the degree of time dilation is 0.5 when you're travelling at 0.866 'c', the green plot shows that the time dilation is 0.707 when you're travelling at 0.707 'c' and the blue plot shows that time is running at 0.866 when you're travelling at 0.5 'c'.

[yor_on]

You made it LeeE?
Very nicely done.

And now

The 'whole circle' please, that's the one I want to see..

(Don't mind if it's not 'proof able', I would just like to see how you visualize it)