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From: dlzc on 20 Dec 2009 12:22
Dear Ste:

On Dec 20, 9:20 am, Ste <ste_ro...(a)hotmail.com> wrote:
> On 20 Dec, 03:17,dlzc<dl...(a)cox.net> wrote:
> > On Dec 19, 5:18 pm, Ste <ste_ro...(a)hotmail.com> wrote:
>
> > > I was contemplating the laws of physics, as
> > > one does, and in the course of some basic
> > > research on the matter I came across the
> > > concept of the "arrow of time", and the
> > > statement that whereas one can move in
> > > both directions in space, currently we can
> > > only move forward in time.
>
> > > Now I'm not an expert in physics, so
> > > perhaps this question may come across as
> > > ridiculously simple. But setting aside for
> > > one moment human perception and common
> > > sense, the question is this: exactly what
> > > leads us to conclude that we are constantly
> > > moving forward in time?
>
> > We don't remember tomorrow.
>
> Droll. But I ask the question in all
> seriousness,

I gave an elegant (or at least not incorrect in any part) and reasoned
answer.

> and because it strikes me that there is
> nothing that suggests an absolute constant
> movement forward along any spacial
> dimension, so why is there an assumption
> of constant movement forward along the
> time dimension (which introduces
> absurdities like travelling into the past)?

Not an assumption. Based on evidence, the cause never follows the
effect.

> On the subject of travelling into the
> past, how would travelling backwards in
> time, be distinguishable from simply
> restoring the universe to the same
> physical state as in the past (but which
> had not actually travelled "back in time"
> in any meaningful sense)?

Violation of conservation of mass/energy. Violation of Pauli
exclusion principle. The same matter cannot be in the same Universe
twice, or at least it has never been seen to do so. There have been
SciFi stories of people that "aged" backwards, and remembered the
future but not the past... the bodies appeared to the rest of us as
moving forward.

> Obviously I haven't posted here before,
> so I'm not sure whether there is anyone
> here who can discuss this at an
> appropriate level.

If you want mathematics and appropriate basis in underlying and
related physical laws, you might post instead on
sci.physics.foundations. It is a moderated newsgroup, so it'll take a
while for your posts and replies to appear.

> And more generally, I'm interested to
> know whether the assumption of forward
> movement is not just a product of
> subjective human intuitions (and
> bearing in mind that every paradigm
> shift in science has involved throwing
> out what was previously held as
> unquestionable).

It is not an assumption. It is the result of experiment. Phenomenon
in systems have been found to be irreversible. "The Arrow of Time"
applies only to systems, much as "population mean" applies only to
populations.

I'd suggest you question the "assumption" of gravity in a similar
way. Might as well try something that Nature can speak directly to
you about.

David A. Smith
From: Simple Simon on 20 Dec 2009 13:19
Ste wrote:
> I was contemplating the laws of physics, as one does, and in the
> course of some basic research on the matter I came across the concept
> of the "arrow of time", and the statement that whereas one can move in
> both directions in space, currently we can only move forward in time.
>
> Now I'm not an expert in physics, so perhaps this question may come
> across as ridiculously simple. But setting aside for one moment human
> perception and common sense, the question is this: exactly what leads
> us to conclude that we are constantly moving forward in time?

from:
http://www.timecrazy.org/pdfs/Brief_History_of_Time.pdf

9. Arrows of Time
'There are at least three different arrows of time. First, there is the
thermodynamic
arrow of time, the direction of time in which disorder or entropy increases.
Then,
there is the psychological arrow of time. This is the direction in which we
feel time
passes, the direction in which we remember the past but not the future.
Finally there
is the cosmological arrow of time. This is the direction of time in which
the universe is
expanding rather than contracting.'
10. Pointing the Same Way
'I have shown that the psychological arrow is essentially the same as the
thermodynamic arrow. The no boundary proposal for the universe predicts the
existence of a well-defined thermodynamic arrow of time because the universe
must
start off in a smooth and ordered state. And the reason we observe this
thermodynamic arrow to agree with the cosmological arrow is that intelligent
beings
can exist only in the expanding phase.'


From: Sue... on 20 Dec 2009 16:21
On Dec 19, 7:18 pm, Ste <ste_ro...(a)hotmail.com> wrote:
> I was contemplating the laws of physics, as one does, and in the
> course of some basic research on the matter I came across the concept
> of the "arrow of time", and the statement that whereas one can move in
> both directions in space, currently we can only move forward in time.
>
> Now I'm not an expert in physics, so perhaps this question may come
> across as ridiculously simple. But setting aside for one moment human
> perception and common sense, the question is this: exactly what leads
> us to conclude that we are constantly moving forward in time?

If it takes you 3 seconds to change the speed of a
car 1km/sec by pushing on the front bumper then it
should take you 3 seconds to change the speed of the
car by 1km/sec by pushing on the rear bumper.

<< the four-dimensional space-time continuum of the
theory of relativity, in its most essential formal
properties, shows a pronounced relationship to the
three-dimensional continuum of Euclidean geometrical space.
In order to give due prominence to this relationship,
however, we must replace the usual time co-ordinate t by
an imaginary magnitude

sqrt(-1)

ct proportional to it. Under these conditions, the
natural laws satisfying the demands of the (special)
theory of relativity assume mathematical forms, in which
the time co-ordinate plays exactly the same rôle as
the three space co-ordinates. >>
http://www.bartleby.com/173/17.html

"Space-time"
http://farside.ph.utexas.edu/teaching/em/lectures/node113.html

Sue...


From: Inertial on 20 Dec 2009 17:21

"Sue..." <suzysewnshow(a)yahoo.com.au> wrote in message
news:8f25c8d2-a941-4c55-9c28-6e5254d3e86e(a)c34g2000yqn.googlegroups.com...
> On Dec 19, 7:18 pm, Ste <ste_ro...(a)hotmail.com> wrote:
>> I was contemplating the laws of physics, as one does, and in the
>> course of some basic research on the matter I came across the concept
>> of the "arrow of time", and the statement that whereas one can move in
>> both directions in space, currently we can only move forward in time.
>>
>> Now I'm not an expert in physics, so perhaps this question may come
>> across as ridiculously simple. But setting aside for one moment human
>> perception and common sense, the question is this: exactly what leads
>> us to conclude that we are constantly moving forward in time?
>
> If it takes you 3 seconds to change the speed of a
> car 1km/sec by pushing on the front bumper then it
> should take you 3 seconds to change the speed of the
> car by 1km/sec by pushing on the rear bumper.

Irrelevant

> << the four-dimensional space-time continuum of the
> theory of relativity, in its most essential formal
> properties, shows a pronounced relationship to the
> three-dimensional continuum of Euclidean geometrical space.
> In order to give due prominence to this relationship,
> however, we must replace the usual time co-ordinate t by
> an imaginary magnitude
>
> sqrt(-1)
>
> ct proportional to it. Under these conditions, the
> natural laws satisfying the demands of the (special)
> theory of relativity assume mathematical forms, in which
> the time co-ordinate plays exactly the same r�le as
> the three space co-ordinates. >>
> http://www.bartleby.com/173/17.html

Irrelevant

> "Space-time"
> http://farside.ph.utexas.edu/teaching/em/lectures/node113.html

Yet another irrelevant post by spambot sue. I thought you'd gone .. must
have been a bug in your software.


From: Inertial on 20 Dec 2009 19:53

"Henry Wilson DSc." <HW@..> wrote in message
news:lv7ti5l3ku8ehn83bcse2qsi0i4onu856t(a)4ax.com...
> On Sun, 20 Dec 2009 08:20:28 -0800 (PST), Ste <ste_rose0(a)hotmail.com>
> wrote:
>
>>On 20 Dec, 03:17, dlzc <dl...(a)cox.net> wrote:
>>> Dear Ste:
>>>
>>> On Dec 19, 5:18 pm, Ste <ste_ro...(a)hotmail.com> wrote:
>>>
>>> > I was contemplating the laws of physics, as
>>> > one does, and in the course of some basic
>>> > research on the matter I came across the
>>> > concept of the "arrow of time", and the
>>> > statement that whereas one can move in
>>> > both directions in space, currently we can
>>> > only move forward in time.
>>>
>>> > Now I'm not an expert in physics, so
>>> > perhaps this question may come across as
>>> > ridiculously simple. But setting aside for
>>> > one moment human perception and common
>>> > sense, the question is this: exactly what
>>> > leads us to conclude that we are constantly
>>> > moving forward in time?
>>>
>>> We don't remember tomorrow.
>>
>>Droll. But I ask the question in all seriousness, and because it
>>strikes me that there is nothing that suggests an absolute constant
>>movement forward along any spacial dimension, so why is there an
>>assumption of constant movement forward along the time dimension
>>(which introduces absurdities like travelling into the past)?
>>
>>On the subject of travelling into the past, how would travelling
>>backwards in time, be distinguishable from simply restoring the
>>universe to the same physical state as in the past (but which had not
>>actually travelled "back in time" in any meaningful sense)?
>>
>>Obviously I haven't posted here before, so I'm not sure whether there
>>is anyone here who can discuss this at an appropriate level. And more
>>generally, I'm interested to know whether the assumption of forward
>>movement is not just a product of subjective human intuitions (and
>>bearing in mind that every paradigm shift in science has involved
>>throwing out what was previously held as unquestionable).
>
> As you can see, asking intelligent questions here is usually a waste of
> time.

How would you know .. you've not asked any (at least not many)

> People like David Smith respond with entirely circular logic and think
> they are
> making intelligent comments, when in fact they are merely preaching their
> nonsensical relativist religion.

Yeah .. we know you're ant anti-relativist crackpot .. move along.

> Other people claim that time and time flow do
> not actually exist but are just psychological constructs.

I don't think time could be said to not exist, as there are certainly things
that change over time.

That it is seen to 'flow' is possibly a psychological construction. Just
like hearing 'music' is a psychological construction based on vibrations
received in the ear. The vibrations are real, but it being 'music' is
subjective.

And that there is what appears to be a 'now', and that 'now' seems to remain
and things change within it (rather than the other way around), may well be
psychological.

> The whole subject TIME is often classified as philosophy, when in fact it
> is
> very much a physical question.

It really depends on the question being asked

> One might also ask for a physical explanation of
> why 'space' exists. One day these questions will be answered, just as
> 'action-at-a-distance' will. After all, physics is only a few hundred
> years old
> and still very much in its infancy.

True. Though usually questions of 'why' things exist is beyond physics ..
'why' they behave as they do can often be explained .. but then it is really
is more of a question of 'how' it works .. not 'why' (ie giving a purpose to
it).

> In my opinion TIME is a basic dimension, totally unrelated to the spatial
> ones.
> We feel time 'flowing' because we possess fairly accurate biological
> clocks
> that sense that flow.

So we feel time flowing because we feel time flowing.

> To us, time flows at 1 second per second, by definition....

Yet time does not always seem to flow at the same rate. As we get older,
time seem to flow slower. When you're holding your breath a few seconds
seems a long time etc. Its all subjective.

> a statement that is
> plainly circular

Indeed it is

> UNLESS there are at least two time subdimensions. Then, just
> as we can assess the slope of a hill as 'metres UP per metre ALONG', we
> might
> say that "time flows at the rate of n t1 seconds per t2 second".

Or the '1 second per second' is just circular nonsense .. like saying a cars
length is one meter per meter

> As far as past and future are concerned consider this: do all states of
> the
> universe 'always' exist and are we simply 'falling' down the absolute time
> axis?

It depends on what you mean by 'exists'. Obviously the past and future do
not exist now. Did the past exists in the past and will the future exist in
the future ? .. of course. In that sense they exist.

> Then ask yourself this question,"If I wasn't alive, what year would it
> be?"

When?

> The 'present' seems to be fundamentally associated with conscious life.

Yeup

For once you've made a sensible post .. congratulations. There's hope for
you yet :)


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