About the world within? Effects on Time of Speed of Light Travel.

So, I've been reading Paradox: The Nine Greatest Enigmas in Physics, by Jim Al-Khalili and I'm not satisfied by his analysis of the Paradox of Twins. It raises more questions.

The way this paradox is resolved is by observing there is no paradox. To that end we say that the travelling twin experienced acceleration. But what exactly experienced acceleration?

I'm not interested in the paradox per se. What I'm interested in understanding is exactly what force allows for a system (the travelling twin, for instance) to be considered a single unit and to experience the effect of time dilation as a whole. And if this won't somehow spill out to any outer systems. At the scale of an atom our bodies are made up of as much empty space as the universe. But we implicitly know there's a force binding us into a consubstantial object in our own scale.

Now, the solar system, is it too a system. An outer system, at our human scale. It's entire mass counts with both twins. In a trip to the Oort Cloud, within our Sun's gravitational force, if the travelling twin went there and back a few times at the speed of light, wouldn't his mass (and that of his spaceship) contributed to an infinitesimal degree to an expanded lifetime of the Solar System?

If the two twins were two cells in your body, the travelling cell will remain young. The other cell (and the rest of your body) will age normally. Your body will however benefit from the young cell. Your body (the system) didn't experience the trip, but the system will still benefit from it as a whole. It is younger. It's made up of younger mass.

So... without experiencing any acceleration how come can the solar system become younger by the travelling twin actions?

The time dilation is a relationship between coordinate systems and "imaginary clocks," not objects. So it is not tied to the object which is accelerating but actually the coordinate system in which that acceleration is defined. Had you chosen to measure from a different coordinate system you would measure a different degree of effect, however, the physical outcome remains the same.

This is similar and related to the unification of electric and magnetic forces. The degree to which an EM interaction is electrical vs. magnetic actually changes depending on the coordinate system, but it changes in a precise way which conserves the physical behavior of the system, so that different observers all experience a single physical reality. What it is telling us is that our distinction between electrical and magnetic forces is artificial. Same thing with space and time.

The problem I have with this paradox is that the "age" part is not well defined. If I get 10 years younger that means that I will live until I am X+10 instead of X. By if I don't know X and cannot know X, this statement is pointless. We could maybe find a way around this by calculating the average life of millions of micro-organisms and just sending them in a trip and back. The point then is to guarantee that Age = F(time) and not Age = F(time, acceleration) as simplified example. In other words that the travel itself won't affect the aging in any way.

Let us try to prove that. We make a valid experiment in in a subject while it is idle and while it is accelerating. We find that the subjects ages the same. The problem with that is that we just invalidated the paradox, the subject is not younger while returning back.
So since we believe on the paradox being accurate, we expect now that the subject is actually younger when it is accelerating. But then we just show that by definition Age = F(time, acceleration). So there is no paradox.
In other words, if we assume that Age = F(t), we accelerate the subject and now see that this equation we observed before isn't true. That just means one thing: our assumption wasn't true. There is still no paradox. If we can prove that Age = F(t), we make the observation and we in fact see now that Age = F(time, acceleration) then we have a paradox, but this is not the case.

More to the point, if you want to talk about the age of a system, provided you can actually define the age of its components, you need to define that. If it is the sum of ages of all components then I would agree that if a component gets younger the whole system gets younger. So I wouldn't be satisfied either if that is the case and I would just say there are more paradoxes spawned. So the solar system will become younger even without experiencing acceleration provided all the previous assumptions are true.

Quote:

---

What it is telling us is that our distinction between electrical and magnetic forces is artificial. Same thing with space and time.

---

I think in the end it is the opposite. Time and space have their definitions regardless of how you measure them. I imagine (as most people I believe) time not being affected by anything else. So if a clock is affected by acceleration I just accept that a clock doesn't count time in general. To say a clock counts time it needs to meet the criteria based on the pure philosophical definition of time I initially had. The fact that a clock used to meet it, but now it doesn't due to the theory of relativity means again one thing: my initial assumption was wrong. Electromagnetic forces on the other hand don't "conflict" on any definition I have put on them initially. That is why you won't see a famous paradox on electromagnetic forces. These are all of course all a matter of my own personal perspective...

I think that the best explanation I've ever heard was from Stephen Hawking - "Into the Universe with Stephen Hawking"

Stephen Hawking Time travel - YouTube

Mario is well versed in the Master Arthur C Clarke's work - which finely discusses such things through stories- relativity is all i say

youtube "Into the Universe with Stephen Hawking"
he has books too

twins is in universe in a nutshell, and before that the grandfather paradox is in brief history of time - IIRC

An easy way to imagine this is to combine all 3 spatial dimensions into a single spatial
dimension, which we can represent as an East-West direction. Then we represent time
as a North-South direction. If you move diagonally, say NE, you are moving through both
space and time. If you move dead North, you are only traveling through time, and likewise
if you move dead East, you are only travelling through space.
Our own motion here on earth is analagous to moving almost dead North. We are moving
through time at a relatively high rate, and through space at a relatively low rate. Someone
(like the travelling twin) who is accelerating rapidly is moving through time at a slower rate
and moving through space at a faster rate. This is analagous to moving more Easterly in
the above analogy.

It's important to remember that movement through space is not quite as we imagine it in
our common experience of it. It is a movement through the spatial dimension of spacetime.
If you accelerate, you give up some of your motion through time, your clock ticks more
slowly. This is a real effect and is what is experienced by the travelling twin. The theory
of General Relativity deals with this effect. Also it is not just the clocks that slow down.
The clock is just an indicator. Time has slowed down. The travelling twin notices nothing
different.

If you wanted to consider the age of the universe as an average of the ages of it's various
components, then the travelling twin would reduce the age of the universe compared to if
that twin had stayed home. Spacetime varies over the universe. It is not a single uniform
(flat) field. Everything in it contributes.
The travelling twin is not going to run the clock backwards, it is only going to slow it's rate
forward.

The universe does not contain the matter within it. It is created by it.
"Physical objects are not in space, but these objects are spatially extended" - Albert Einstein

Quote:

---

Originally Posted by Mario F.

The way this paradox is resolved is by observing there is no paradox. To that end we say that the travelling twin experienced acceleration. But what exactly experienced

acceleration?

I'm not interested in the paradox per se. What I'm interested in understanding is exactly what force allows for a system (the travelling twin, for instance) to be considered a single unit and to experience the

effect of time dilation as a whole. And if this won't somehow spill out to any outer systems. At the scale of an atom our bodies are made up of as much empty space as the universe. But we implicitly know

there's a force binding us into a consubstantial object in our own scale.

---

The travelling twin can experience a time flow that is different from the "rest" of the universe
because it is travelling along a different path through spacetime. It is not just the direction as
we commonly thing of it. When an object is not acted upon by any external force, it is said
to be in an inertial reference frame. Examples are objects in orbit, objects in freefall, an
object that has been tossed into the air (while it is in flight), or an obect sitting out in deep
space. Even though the object might seem motionless, it is nonetheless travelling through
spacetime. It's path is called a geodesic. Any object travelling along a geodesic is free
of any force like gravity or inertia. It's motion is entirely through time.

True, these objects certainly appear to be moving through space, but each one can perfectly
claim that it is at rest, and it is the rest of the world that is moving. All such objects are governed
equally by the laws of physics. This is given by the principle of relativity.

The stationary twin is in an inertial reference frame (ignoring the gravitational field from the planet
that he might be standing on). He is travelling along a geodesic. You might think of these geodesics
as natural paths, ones that objects will naturally follow unless forced to do otherwise.
The travelling twin though, has been diverted from a geodesic by the forces causing him to accelerate.
He has veered off of the time dimension and is travelling partly along a spatial dimension. He is now
travelling more rapidly along the spatial dimension of spacetime, and more slowly through the temporal
(time) dimension.

This moving object contributes to the universe because it has in fact created part of it. That an object
is spatially extended must also mean that it is temporally extended. They cannot be separated. Just as
cells are bound into a body, the extension of these moving objects are bound into the universe.

The twin paradox is not all that dificult of a paradox, and is usually introduced in the study of special relativity.
It is in the context of the special theory that it seems to form a contradiction. The special theory only deals
with objects and observers in an inertial (non accelerating) reference frame. For such observers, each will
see the other's clock as running more slowly than their own. And there is the paradox: how can each one both
be slower than the other? The paradox is resolved by the fact that the twins are actually not both in inertial
reference frames; only the travelling one is.
Or at least that is one form and resolution of the twin paradox.

Now the two twins could pass each other in opposite directions at uniform speed. Both would be in inertial
reference frames and so neither should experience time dilation. Yet each will observe the other's clock
as running slower than his own. Here I think is the real paradox. Unlike the classic twin paradox, it is possible
for the two twins to meet up again and compare clocks, without either one undergoing any acceleration.
They can't possibly both see each other's clock as being slower than their own. So was it all an illusion?
I believe it isn't. I would describe it as an offset in time. Time didn't slow, it just lagged. Like a clock
that was set 10 minutes slow but still ran at correct speed.

Quote:

---

Originally Posted by megafiddle

Now the two twins could pass each other in opposite directions at uniform speed. Both would be in inertial
reference frames and so neither should experience time dilation. Yet each will observe the other's clock
as running slower than his own. Here I think is the real paradox. Unlike the classic twin paradox, it is possible
for the two twins to meet up again and compare clocks, without either one undergoing any acceleration.
They can't possibly both see each other's clock as being slower than their own. So was it all an illusion?
I believe it isn't. I would describe it as an offset in time. Time didn't slow, it just lagged. Like a clock
that was set 10 minutes slow but still ran at correct speed.

---

They cannot though "simultaneously" see each other's clock to make this observation. You always need a specific reference point. Since you are describing the way you see it, what matter is how you count time. Then you can take a clock from both travelers and compare it to yours. In which case you can then check the difference from a specific reference point than the difference between two reference points "at the same time" (same time according to who?).

What you are also counting then is the different measurements in those 3 clocks. If you used an atomic clock then you counted a difference in frequencies of the atoms. I would thus say that it indeed seems like a "slowing down in time" rather than a lagging. Like the atoms actually moved slower compared to the ones on the reference point. If you combine this with general relativity it just shows that both acceleration and gravitational fields affect the atom's movement (I know I am oversimplifying...). Which is a bit easier to comprehend as you can expect gravity to interact with something that has a mass, like an atom, and movement (from acceleration) affects movement (the frequency of the atom).

Quote:

---

Originally Posted by C_ntua

They cannot though "simultaneously" see each other's clock to make this observation. You always need a specific reference point. Since you are describing the way you see it,

what matter is how you count time. Then you can take a clock from both travelers and compare it to yours. In which case you can then check the difference from a specific reference point than the

difference between two reference points "at the same time" (same time according to who?).

---

Actually, you can't do that. A separate third observer only has the reality of his own reference frame. One of the points
of special relativity is that twin A has a perfectly valid reference frame from which he can judge reality. What twin A
observes is real, in every sense of the word. Another point of the theory is that the speed of light is constant relative
to any and all observers. The theory itself was not the introduction of these points into physics. That was done by the
principle of relativity for the first point and Maxwell's field equations for the second point. What the theory did was bring
the two together. These two points would be incompatable using Newtonian physics.

Einstein's "bouncing photon" thought experiment illustrates that time must change in order for the speed of light to remain
constant. When twin A observes twin B's clock as running slower than his own, the slower speed of twin B's clock is every
bit as real as the "normal" speed of his own clock. Likewise, when twin B sees twin A's clock as running slower than his own,
that is also a reality for twin B. You can't introduce a separate observor to see what is "really" going on.

Quote:

---

Originally Posted by C_ntua

What you are also counting then is the different measurements in those 3 clocks. If you used an atomic clock then you counted a difference in frequencies of the atoms. I would

thus say that it indeed seems like a "slowing down in time" rather than a lagging. Like the atoms actually moved slower compared to the ones on the reference point. If you combine this with general

relativity it just shows that both acceleration and gravitational fields affect the atom's movement (I know I am oversimplifying...). Which is a bit easier to comprehend as you can expect gravity to interact

with something that has a mass, like an atom, and movement (from acceleration) affects movement (the frequency of the atom).

---

General relativity does have some differences. When you reunite two clocks from inertial and noninertial reference frames,
there will be a difference. More time will have passed in the inertial frame. But there is another difference. You can place
twin A at the surface of a large planet and twin B in a synchronous orbit above him. They do not move in relation to each other,
distance wise. They can observe each other's clocks directly and continuously. Maybe using precise strobes. And twin A's
clock is going to run slower on the planet surface. It is not that time is the same and the atoms are moving more slowly. It
is that time itself has slowed. The atoms are following the laws of physics just as they would anywhere else.

There is a good site with animated illustrations of the "bouncing photon". I will put it up here if I can find it.

My use of the term "lagging" is only from lack of a better one. I think it is clear that two twins who are each in inertial reference
frames will find that their clocks are still synchronized when they meet up again. Since the slowing of twin B's clock is a reality
for twin A, something in addition to slowing must have occured. At this point I don't understand where speeding up of the clock
might have occured, for example. The only other change that you can have besides rate with a clock (or time) is offset.

I found the site. This has some good explanations and animations, especially for the bouncing photon clock::

Time Dilation, Length Contraction and Simultaneity (from Einstein Light)

The play, stop, etc buttons are just above each animation image.
You might not see the animations if your security settings are on "high".

Previously I said this:

So was it all an illusion?
I believe it isn't. I would describe it as an offset in time. Time didn't slow, it just lagged. Like a clock
that was set 10 minutes slow but still ran at correct speed.

I think I need to correct that. Time did slow down. But there was an additional change which I called
an offset or lag. Maybe "shift" is a better term.

Also, I have a question myself.

In my own twin paradox, the two twins are travelling in high speed orbits about the same planet,
but in opposite directions. The orbits are slightly tilted from each other so that the twins don't
collide. They pass each other at two points in the orbit, 180 degrees apart. At these two points
they have an opportunity to observe the bouncing photon in the other's ship. The bouncing photon
constitutes the clock. Each bounce is a "tick" of the clock. Each twin sees the other twin's clock
ticking more slowly than his own at each passing. This is not a problem or paradox in itself; it is
exactly to be expected from special relativity. Each twin's observations are their own individual
realities based on their reference frames.

Now at any point, they can decelerate equally to a stop and compare clocks. Because they were
both in inertial reference frames, their two clocks will agree. Both experienced the same acceleration
while stopping, so there experience is symmetrical.

Again this is as must be expected from special relativity (and general relativity for the stopping part).
But how can one twin continue to observe the "moving" clock (the other twin's clock) as moving more
slowly than his own, and then have the two clocks show up exactly in sync when they are compared?

There is the paradox.

If I am thinking about this correctly, the path of the bouncing photon will always be longer for the "moving"
clock regardless of whether it is receding or approaching. So the "stationary" twin will always see the
"moving" twin's clock as running slower. So something additional must be happening. Could the motion
of the "moving" clock towards the observer compensate for the slowing of the clock in the same way
that the motion would cause a blue shift?

Quote:

---

Originally Posted by Mario F.

The way this paradox is resolved is by observing there is no paradox. To that end we say that the travelling twin experienced acceleration. But what exactly experienced

acceleration?

---

Imagine you are out in deep space, just floating there in zero G. Some distance away a tether is anchored
somehow and someone is attached to the free end of the tether and travelling around in a large circle,
restrained by the tether. What would you observe? You would see them travelling in a large circle, off to
one side of your position.
Now suppose you are sitting on a rediculously high platform above a planet. Someone is travelling in an
orbit around the planet. What would you observe? You would see them travelling in a large circle, off to
one side of your position.

In the first case it is your circulating neighbor that experiences a force, in that case a centrifugal force.
In the second case it is you that experience a force, the gravitational force. Both are accelerating forces
and have the same effect.
In the first case, time will be slower for your circulating neighbor as it is him that was accelerating; he
experienced a force, you did not.
In the second case, time will be slower for you, as you are experiencing a force, the orbiter experiences
no force.

Quote:

---

Originally Posted by Mario F.

I'm not interested in the paradox per se. What I'm interested in understanding is exactly what force allows for a system (the travelling twin, for instance) to be considered a

single unit and to experience the effect of time dilation as a whole.

---

We tend to think of the world in the Newtonian sense, with everything behaving just as it does in our own
limited experience (relativistic effects are only observed at significant speed, ie approaching light speed).
We also tend to think of time as an independant universal constant. In such a world, everything can move
around through space alone, while their motion through time remains fixed and determined by the cosmic
clock.
Also in such a world, one direction or path is no differect than any other. The world would be flat, not flat as
in two dimensional, but flat as in being uniform and the same in all directions and locations. It is not hard to
imagine that objects could move around in such a world with no effect on their age.

We can imagine Newtonian space if we think about a pool table. If you wanted to describe the movement
of the 8 ball across the table surface, you would only need a direction and a velocity. The 8 ball's movement
through time would be independant and unaffected by it's motion through space, in this Newtonian space.
There would be no forces there that acted on time or the 8 ball's age.

In Einstein's model of the universe, time and space are not independant. They are in fact two parts of the
same thing - spacetime. Likewise, the motion of an object through spacetime is always through both space
and time combined.

Back to the Newtonian pool table, a ball can move within two dimensions. It can move along the shorter
dimension of the table (side to side) or along the longer dimension (end to end - pool tables are rectangular).
Now suppose the ball must always be in motion at some constant speed. If you interfere with the ball's motion
and change it's direction, it's movement will change in both dimensions. If it is now moving more in an end to
end direction, it will be moving less in a side to side direction (and vice versa). Since this a Newtonian table,
time is unaffected. In our relativistic world, things appear virtually the same on a pool table, but that is only
because the relativistic effects are miniscule on this scale of things.

It will seem unusual that the ball must always be moving at a constant speed, but that is important to the analogy.
In relativistic space, objects always move at a constant speed. We don't observe that because we only see the
spatial component and temporal components separately. The variations in speed and direction that we normally
see in objects also have an effect on their travel through time (the temporal dimension), but it is unmeasurable.

Now we can imagine a relativistic pool table. Since we need to use one dimension for time, we only have one
dimension left to represent all 3 spatial dimensions. Nonetheless it should work as well, as we are primarily
interested in the time dimension and it's relation to the spatial. We only need one to represent space. Suppose
that the long dimension of the table represents space and the short dimension represents time. Also the ball,
which again represents an object in the universe, must move at some constant speed (on the table). It should
be easy to see that the object could move entirely through space (end to end on the table), or entirely through
time (side to side on the table), or some combination of the two (a diagonal movement).
We, for example, sitting here on earth, would be like a ball moving in a side to side direction, very slightly angled
because of the earth's gravity.

But there is a more important difference between the Newtonian and relativistic tables. The Newtonian table is flat.
The ball has no preference in it's direction, except to continue in it's current direction. The relativistic table though,
has a "grain" or "texture". Left to themselves, balls on a relativistic table will tend to move from side to side only. It
requires some type of force to alter their direction from temporal to spatial (from side to side to lengthwise).

And so it is with spacetime. It has a grain, or network of "preferred directions". These are called geodesics or world
lines. Left to themselves, objects will follow geodesics. The direction of the geodesics lie in the direction of the time
dimension. The spatial dimensions lie at angles to the geodesics. So left to itself, an object will travel at maximum
speed through time and at zero speed through space.

It requires a force to deflect an object from it's movement along a geodesic. This might be a force causing an object
to change it's direction, or a force causing an object to change speed (both are changes in spatial velocity).
Or it might be a gravitational force (which is equivalent to an accelerating force). In all these cases the object is no
longer travelling exclusively along the temporal dimension, while the force is present. Some of it's movment will have
been diverted to the spatial dimension. It will have travelled through time more slowly.

Quote:

---

Originally Posted by Mario F.

To that end we say that the travelling twin experienced acceleration. But what exactly experienced acceleration?

What I'm interested in understanding is exactly what force allows for a system (the travelling twin, for instance) to be considered a single unit and to experience the effect of time dilation as a whole.

---

I assume, you can tell how much something is moving, insomuch as time dilation is concerned, by how it's movement compares to the matter who's gravitational field it's most affected by.

In the case of the platform on a planet, and the orbiter of the planet: The platform is moving along with the planet, hence no "movement" / time dilation, but the orbiter is moving contrary to the planet, hence "movement" / time dilation.

Quote:

---

Originally Posted by Yarin

I assume, you can tell how much something is moving, insomuch as time dilation is concerned, by how it's movement compares to the matter who's gravitational field it's most affected by.

---

You can only define movement in relation to yourself, your own reference frame. There is no such thing as absolute motion.

Quote:

---

Originally Posted by Yarin

In the case of the platform on a planet, and the orbiter of the planet: The platform is moving along with the planet, hence no "movement" / time dilation, but the orbiter is moving

contrary to the planet, hence "movement" / time dilation.

---

The reference frame is that of the observer on the platform. The movement of the orbiter is in relation to the platform.
The question here is the forces experienced by the various observers. The orbiter experiences none. That is necessarily the case
if he is in orbit. It has nothing to do with rotation of the planet beneath him. The orbiter experiences no general relativistic time dilation.

The forces on the platform would depend on the rotation of the planet. I did not specify a height for the platform; if it were right at
synchronous orbit height, the accelerating forces would be zero. However, I did imply that the orbiter would be moving with respect
to the platform. Therefore the platform could not be at a height that would also place it in zero G like the orbiter. The forces on the
platform then will either be gravitational if it's below synchronous height, or cetrifugal if it is above synchronous height. Either way,
there are accelerating forces on the platform. The observer on the platform will experience general relativistic time dilation.

Quote:

---

Originally Posted by megafiddle

There is no such thing as absolute motion.

---

I never claimed anything of the sort.
You write mile long posts, but can't even read my small post. :-/

Quote:

---

Originally Posted by Yarin

I never claimed anything of the sort.
You write mile long posts, but can't even read my small post. :-/

---

It appears you are saying that there is a preferred reference frame, that motion should be judged relative to the most influential gravitational mass.

That implies that there is something special about the planet. You said:

The platform is moving along with the planet, hence no "movement" / time dilation, but the orbiter is moving

contrary to the planet, hence "movement" / time dilation.

That could only be true if there were absolute motion.

Quote:

---

Originally Posted by megafiddle

It appears you are saying that there is a preferred reference frame, that motion should be judged relative to the most influential gravitational mass.

---

At least in regard to time dilation, yes.

Quote:

---

Originally Posted by megafiddle

That implies that there is something special about the planet. You said:

The platform is moving along with the planet, hence no "movement" / time dilation, but the orbiter is moving

contrary to the planet, hence "movement" / time dilation.

That could only be true if there were absolute motion.

---

Only insomuch as the planet is hypothetically anchored.
Example: When you drive a car at 80mph, as you know, your car is actually travelling ks and ks of mph through space, around the sun along with the planet. But we don't say that, nor do we even consider that when reasoning about physics of such objects here on Earth, because Earth is our anchor, or as you put it, reference frame.
Obviously, we do this because Earth's gravity dominates the relevant space. I purpose that the effects of time dilation from movement can be anchored in the same way.

EDIT: Not claiming that there is actually any truly absolute movement, location, rotation, distance, etc.

Quote:

---

Originally Posted by Yarin

At least in regard to time dilation, yes.

---

Thanks for clarifying.

If you mean that the gravitational source should be used to determine the amount of time dilation,
then that is true. But that can be observed from any refernce frame. And all are equally valid.
Certainly you would use the one you are in if that is your vantage point of interest.

Quote:

---

Originally Posted by Yarin

Only insomuch as the planet is hypothetically anchored.
Example: When you drive a car at 80mph, as you know, your car is actually travelling ks and ks of mph through space, around the sun along with the planet. But we don't say that, nor do we even consider

that when reasoning about physics of such objects here on Earth, because Earth is our anchor, or as you put it, reference frame.
Obviously, we do this because Earth's gravity dominates the relevant space. I purpose that the effects of time dilation from movement can be anchored in the same way.

EDIT: Not claiming that there is actually any truly absolute movement, location, rotation, distance, etc.

---

But the reason we can do that is not because of the gravitational field. It is because any reference frame
is just as valid as any other. We could use the moon and still observe an equally valid reality.
The effects of time dilation will appear one way from the earth and another way from the moon. Both are
real.

Not sure if I'm misunderstanding though.

Well I guess then GR represents individuality and unity in One. Everything is One since all is part of the space-time continuum. And Yet all is Individual since any singular perspective is valid. @megafiddle You said there is no Absolute or more important frame of reference. But what frame of reference is used when cosmologists treat the Universe as a singular object?

Quote:

---

Originally Posted by gemera

But what frame of reference is used when cosmologists treat the Universe as a singular object?

---

They can't really. The speed of light will determine also the speed at which we can gain information.

Quote:

---

Originally Posted by gemera

You said there is no Absolute or more important frame of reference. But what frame of reference is used when cosmologists treat the Universe as a singular object?

---

I don't think you need one. You can imagine that the whole universe travels with the speed of light from an imaginary "God's frame". We can just claim that our frame is actually "stationary" and the imaginary "God's frame" is actually the one moving with the speed of light. We are also not fully aware of everything in the Universe to ever treat it as a singular object. Dark energy and dark matter shows that there is more to it than thought a few years back.

Quote:

---

Originally Posted by megafiddle

Also, I have a question myself.

In my own twin paradox, the two twins are travelling in high speed orbits about the same planet,
but in opposite directions. The orbits are slightly tilted from each other so that the twins don't
collide. They pass each other at two points in the orbit, 180 degrees apart. At these two points
they have an opportunity to observe the bouncing photon in the other's ship. The bouncing photon
constitutes the clock. Each bounce is a "tick" of the clock. Each twin sees the other twin's clock
ticking more slowly than his own at each passing. This is not a problem or paradox in itself; it is
exactly to be expected from special relativity. Each twin's observations are their own individual
realities based on their reference frames.

Now at any point, they can decelerate equally to a stop and compare clocks. Because they were
both in inertial reference frames, their two clocks will agree. Both experienced the same acceleration
while stopping, so there experience is symmetrical.

Again this is as must be expected from special relativity (and general relativity for the stopping part).
But how can one twin continue to observe the "moving" clock (the other twin's clock) as moving more
slowly than his own, and then have the two clocks show up exactly in sync when they are compared?

There is the paradox.

---

That is what I meant about not being able to claim simultaneity of the events. Think on how the whole thing will seem from one of the twins point of view and how it seems from a stationary observer which describes it the way you did. For the stationary observer time will dilate the same for both twins due to the whole symmetry. For a twin's point of view though the other twin (and stationary observer) is accelerating/decelerating since their speed is constantly changing direction, so their "passing of time" constantly changes. Sometimes it seems slower, sometimes it seems faster. If we imagine that each twin changes their speed by a function v(t) that is the same for both, you could calculate the sum of relative dt. That sum will be found the same (I believe). So no paradox.

I think your description of "lagging" fits perfectly here, sorry to doubt you before :) The information travels here also with the speed of light, which is comparable to the moving observer's speeds. So when one sees the photon bouncing back to them that means that it has left the other spaceship actually at a different time. So lagging of time seems suitable and it will be the same lagging for both observers. When they are both in the same frame then the effect of their motion doesn't affect time. So they can simultaneously look at each other's clock and get the same time. There is no lagging in this case.

That is also the main reason there is the claim that information doesn't travel faster than light. That would break the theory of relativity due to these kind of paradoxes. Even if you look at quantum teleportation where an effect can travel instantaneous (thus faster than light) to actually read the effect we need some information. Which we cannot get with a speed faster than the one of light.

Quote:

---

Originally Posted by C_ntua

We are also not fully aware of everything in the Universe to ever treat it as a singular object. Dark energy and dark matter shows that there is more to it than thought a few years back.

---

Nor we could ever be. Or God for that matter (or a Demon, as another paradox names it).

Limitations of space:
Imagine a supercomputer that knew every single atom on the universe and stored that information in its memory. Now the Supercomputer has a problem. To truly know everything about the universe the supercomputer needs to know also the location of every of its own atoms, including its memory banks. But then this information needs to be stored in new memory, which itself would require new information to be stored, ad aeternum.

Limitations of Time:
The above is a simple representation of the problem that could be easily translated to any creature brain. But there are other considerations. Information travels at the speed of light. A photon has to reach the supercomputer for the information it carries to be stored. At the speed of light we know distances become 0. But we know that this says nothing about time. So a stationary supercomputer would still have to wait for this information according to its own time frame of reference, much like we need to wait for information when our astronauts go to the Moon. So, our supercomputer couldn't know everything in the Universe. Information would come dripping like the light of the different stars we observe on the night sky. In order for it to really know everything about the universe, our supercomputer would need to be travelling at the speed of light to be able to be everywhere in the universe and collect that data. But... only light can travel at the speed of light, not supercomputers.

Every measurement of time requires motion. In space in between large systems there is a large absence of motion. If time itself is only measured by its affect on objects then objects must interact in order for time to be measured in its passage.

Now time could exist in its passage completely seperate from our existence.

Code:

---

for(int CurrentTime = StartOfTime; CurrentTime < EndOfTime; CurrentTime++)
{
  if(People.AbleToMeasureTime())
    People.MeasureTime();
}

---

But because the ability to measure time is conditional to something that is subject to time, then it's measurement itself can never be accurate. The unfortunate part about our situation is that we aren't even anywhere near as close to time in that loop either. How are we to even assume to understand things that we cannot measure and cannot simulate. This is where a concept of relativity and uncertainty must be inserted to explain why no two measurements are the same and no two experiments are the same. Start throwing the human 1/10 nueron misfires into the equation and any result is going to get messy.

Quote:

---

Limitations of space:
Imagine a supercomputer that knew every single atom on the universe and stored that information in its memory. Now the Supercomputer has a problem. To truly know everything about the universe the supercomputer needs to know also the location of every of its own atoms, including its memory banks. But then this information needs to be stored in new memory, which itself would require new information to be stored, ad aeternum.

---

Does a human know where itself is without violating this? The concept of entropy memory storage shows that the system as a whole could be reduced in its storage by denoting its most common numeric frequencies occuring within the system. The supercomputer would be the system. Its just unfortunate that 90% of the computers memory would be storage of the data (dark matter? lol).

What if I suggested inifinities and paradices is our inability to finish measuring or counting something rather than a flaw in the system as a whole. Basicly infinity could be thought as the difference between the amount of space needed to know everything in the universe and the amount of space we possess as a species in unision (because obviously not every human being contributes to a positive advancement).

Our number systems will advance (beyond a decimal is a must to preserve space when denoting large numbers and still maintaining 100% accuracy rather than scientific notation rounding) and our ways of measurement will change. Concepts of impossibilities through contradiction will die as we discover measurable truths. But the concepts are very stimulating none the less and lead one to create the experiments needed to prove reality to each other.

Reality in itself is a constant and any infinity or paradox is merely our lack of ability to account for every situation accurately.

Quote:

---

Originally Posted by Mario F.

Nor we could ever be. Or God for that matter (or a Demon, as another paradox names it).

Limitations of space:
Imagine a supercomputer that knew every single atom on the universe and stored that information in its memory. Now the Supercomputer has a problem. To truly know everything about the universe the supercomputer needs to know also the location of every of its own atoms, including its memory banks. But then this information needs to be stored in new memory, which itself would require new information to be stored, ad aeternum.

---

If you believe that the laws of physics are constant, that is not entirely true as we can predict where atoms go without needing to observer and store their path. If I tell you there are 1000 objects with this exact same attributes one being apart from the other exactly a given space, you wouldn't need to store each and every object.
Assume thus that there is a Demon that lived from the beginning of times and had built a supercomputer. The Demon find out the laws of physics and about themselves and also built a supercomputer. It comes across matter before the Big Bang and measures all its atoms and stores it in the supercomputer's memory. Since the Demon has all the information about the laws and matter they could predict everything that will happen ever. Lets assume that there is no external energy or matter, there is no God that would change the equations and free will doesn't change anything either. No way to prove they don't exist, but no way to disprove this either. In this case what the Demon cannot do is store the location of each atom in the super computers memory. But is it wrong to say that he knows it? I know how an infinite series of bits going 101010... are even if I cannot possibly store infinite bits in my brain.

Quote:

---

Originally Posted by Mario F.

Limitations of Time:
The above is a simple representation of the problem that could be easily translated to any creature brain. But there are other considerations. Information travels at the speed of light. A photon has to reach the supercomputer for the information it carries to be stored. At the speed of light we know distances become 0. But we know that this says nothing about time. So a stationary supercomputer would still have to wait for this information according to its own time frame of reference, much like we need to wait for information when our astronauts go to the Moon. So, our supercomputer couldn't know everything in the Universe. Information would come dripping like the light of the different stars we observe on the night sky. In order for it to really know everything about the universe, our supercomputer would need to be travelling at the speed of light to be able to be everywhere in the universe and collect that data. But... only light can travel at the speed of light, not supercomputers.

---

I assumed somehow you can see the Universe when its static and when matter doesn't move away from each other creating a race condition. If that time existed and the Demon was there then they could know by predicting. I also mentioned the limitations of quantum teleportation but that could be just our own current limitations. The Demon doesn't need to be limited by the uncertainty principle. It does if it was to observer the world the way we observer it, but imagine if it could use somehow vision with particles much smaller than the observable matter in the sense that their interaction wouldn't practicaly affect the state if matter as we can perceive it. In this case there is an imaginary transfer of information faster than the speed of light. Or you can simply state that those imaginary particles could by definition travel faster than the speed of light.


But lets see this purely philosophical. Imagine an omnipotent and all-knowing God. Then you ask him, "hey, can you create a box that you I can hid something from you?" If God could, then he wouldn't be able to see inside the box, thus not being all-knowing. If God couldn't, then there is something God cannot do, so cannot be omnipotent. If you remove the omnipotent or the all-knowing, then there is no problem (this is a whole other discussion itself...). So lets just say that God was only all-knowing. Could you ever prove that there is something God doesn't know? No. Could God prove that they are all-knowing? No, since God cannot know what they don't know. You could safely state that God just believes they know everything and that there could be something they will find out in the future. Or something that exists but God can never find out.
As humans we learn more and more, yet we keep having more and more questions. There could be a time that we have answered all our current questions and we have no answers. Unlikely, but not impossible. At that time, could we not claim that we are all-knowing in the way we describe a God being all-knowing? To say it differently, if I was a being that could only observer one thing, if I could see all there is to that one thing, wouldn't I get the impression that I know everything from a scientifically point of view? I could say there is something else I haven't discovered, the same way humans say there is a God we cannot fully perceive, but that is beyond science from my point of view. As long as we don't have an indication of an existence of something we claim it as "non existent" in the context of science, bottom line being that we define what we "can know". Since we define what we "can know" and we define what we know, it is entirely up to as to claim that we know or we don't know everything.

Quote:

---

Originally Posted by gemera

Well I guess then GR represents individuality and unity in One. Everything is One since all is part of the space-time

continuum. And Yet all is Individual since any singular perspective is valid. @megafiddle You said there is no Absolute or more important

frame of reference. But what frame of reference is used when cosmologists treat the Universe as a singular object?

---

I believe it would be no different than any other reference frame. The reference frame is basically just a vantage point.
It's important property is that one single set of physical laws apply to any and all reference frames. There is no test that
you can perform to determine if you are "really" in motion or not. Hence no absolute motion.

Or do you mean a reference frame in some other way? Something other than as it's used in special relativity?

Quote:

---

Originally Posted by C_ntua

That is what I meant about not being able to claim simultaneity of the events. Think on how the whole thing will seem from one of the twins point of view and how it seems from a stationary observer which describes it the way you did. For the stationary observer time will dilate the same for both twins due to the whole symmetry. For a twin's point of view though the other twin (and stationary observer) is accelerating/decelerating since their speed is constantly changing direction, so their "passing of time" constantly changes. Sometimes it seems slower, sometimes it seems faster. If we imagine that each twin changes their speed by a function v(t) that is the same for both, you could calculate the sum of relative dt. That sum will be found the same (I believe). So no paradox.

---

That sounds rights. It seems that must be the case.

Quote:

---

Originally Posted by C_ntua

If you believe that the laws of physics are constant, that is not entirely true

---

Really? Well, those aren't my thoughts. You may want to argue against the time and space impossibility of a supercomputer that knew everything about the universe. But you'll need to find a theoretical physicist for that.

In any case, to refute your argument, look more closely at it. Now look more closely at how a all-knowing supercomputer is an impossibility due to its space and time limitations as argued by theoretical physicists (sorry for pushing the argument from authority buttons, but I can't help since it's a far more elegant argumentation that what I personally could). Now... would your demon ever be able to build such a machine? He wouldn't. Exactly because of the limitations imposed by it. There was no new matter since the big bang. All matter that exists today, existed then. So that supercomputer would face then the same impossibility of existence as it faces now.

Quote:

---

Originally Posted by C_ntua

As humans we learn more and more, yet we keep having more and more questions. There could be a time that we have answered all our current questions and we have no answers. Unlikely, but not impossible. At that time, could we not claim that we are all-knowing in the way we describe a God being all-knowing?

---

No, not really. You are confusing a general knowledge of the rules of the universe, which is what human knowledge seeks, with omniscience which is the attribute some give to God. We describe a God all-knowing as being omniscient. Having infinite knowledge. The box you speak a little above is a known thought experiment that tries to refute both omnipotence and omniscience.

Quote:

---

Originally Posted by megafiddle

I believe it would be no different than any other reference frame. The reference frame is basically just a vantage point.
It's important property is that one single set of physical laws apply to any and all reference frames. There is no test that
you can perform to determine if you are "really" in motion or not. Hence no absolute motion.

---

Maybe I should have framed my question more clearly. I had in mind the big-bang
theory. Cosmologists create models using GR and are able to calculate certain
values like the age of the Universe and its size and thus how much of the universe we can
actually observe etc.

They are also able to replicate the expansion of the Universe etc.

So all these measurements must take place in a frame of reference.

And wherereas I agree that that the laws of GR are the same for all observers and
no frame of reference is more valid or special than another, it just seems that the
actual frame of reference in which the whole Universe is expanding could be described
as a 'special' frame of reference.

And could be used as a default absolute against which other frames could be measured?

For instance suppose we hypothesise alien cosmologists all over the universe as well.

Presumably it would not matter what frame of reference cosmologists all over the Universe
were actually in - if the theory is correct - they should all agree about this reference
frame of the expanding universe?

Quote:

---

Originally Posted by gemera

Maybe I should have framed my question more clearly. I had in mind the big-bang
theory. Cosmologists create models using GR and are able to calculate certain
values like the age of the Universe and its size and thus how much of the universe we can
actually observe etc.

They are also able to replicate the expansion of the Universe etc.

So all these measurements must take place in a frame of reference.

---

Not completely sure about this, but I believe the universe's origin, history, age, etc. are referenced to our
own position in the universe and it's current state. So the age for example is based on time as it currently
progresses, and it's size is based on what we can see in all directions (and extrapolate beyond that).
All of this works as if we are at the center of the universe, which in effect we are. But still there is nothing
special about this; any point in the universe can claim to be at the center.

Quote:

---

Originally Posted by gemera

And wherereas I agree that that the laws of GR are the same for all observers and
no frame of reference is more valid or special than another, it just seems that the
actual frame of reference in which the whole Universe is expanding could be described
as a 'special' frame of reference.

And could be used as a default absolute against which other frames could be measured?

For instance suppose we hypothesise alien cosmologists all over the universe as well.

Presumably it would not matter what frame of reference cosmologists all over the Universe
were actually in - if the theory is correct - they should all agree about this reference
frame of the expanding universe?

---

In the Big Bang model, there is nothing external to judge it by. It can be judged only in reference to itself.
In that case the alien cosmologists will all agree on general characteristics of the universe, because they
are in equivalent reference frames. They will disagree though based on the relative motion that they share
with each other. Each is at the center, and each sees the others are receding away from himself, along
with the rest of the universe.

I'm pretty sure the big bang theory is not extrapolated from our
own reference system, or position in the universe.

Well, apart from the actual cultural/scientific/math units of measurement etc of which any alien species would have their own equivalent, and also the observations that led to the theory in the first place.

But if alien cosmologists were to follow our own lines of enquiry they would have an equivalent of GR and end up with similar models of the Universe, which they could THEN use to extrapolate to their own local systems. Which is what cosmologists on earth do.

Maybe.

Are you saying there could be reference frame outside of the universe's origin?
That there is some observation point where the Big Bang itself could be observed?

That is what I would disagree with. In my understanding of relativistic space, there is nothing outside our universe,
nor was there ever anything outside of it. There was nothing here at all until the "explosion" of the cosmic egg. And
then there was only what was in the "sphere" of the expanding universe.

Quote:

---

Originally Posted by megafiddle

Are you saying there could be reference frame outside of the universe's origin?
That there is some observation point where the Big Bang itself could be observed?

---

I don't think he's trying to say that. Although it certainly looks that way ;)

Quote:

---

Originally Posted by megafiddle

That is what I would disagree with. In my understanding of relativistic space, there is nothing outside our universe,
nor was there ever anything outside of it. There was nothing here at all until the "explosion" of the cosmic egg. And
then there was only what was in the "sphere" of the expanding universe.

---

The philosophy that the Big Bang is the first cause is superfluous to the relativity of space.

Quote:

---

Originally Posted by Mario F.

No, not really. You are confusing a general knowledge of the rules of the universe, which is what human knowledge seeks, with omniscience which is the attribute some give to God. We describe a God all-knowing as being omniscient. Having infinite knowledge. The box you speak a little above is a known thought experiment that tries to refute both omnipotence and omniscience.

---

I meant actually having full knowledge (even temporary) in the field of cosmology. That is not omniscience as the later would involve knowledge from all fields.

Regarding the demon I implied, without clearly stating so, that it can be a being from another dimension in a way that it can observe this dimension without changing its state (as we do) and without necessarily our limitations of time. The same can be said for the imaginary supercomputer and that I believe would get away with most common paradoxes and limitations. For example the supercomputer wouldn't need to have memory for itself or the demon as those our out of the universe in question. This would of course imply that the demon could still not know everything in its own dimension so you somehow transfer the problem, but still strictly in the field cosmology as we mean and observe it the demon I believe could have full knowledge.

I am sure I would disagree with a lot of theoretical scientists but they would probably say that I am cheating by removing the demon from the universe (which probably I am a bit).

Quote:

---

Originally Posted by megafiddle

That is what I would disagree with. In my understanding of relativistic space, there is nothing outside our universe,
nor was there ever anything outside of it. There was nothing here at all until the "explosion" of the cosmic egg. And
then there was only what was in the "sphere" of the expanding universe.

---

There has to be something before the Big Bang as otherwise we are just "conveniently" setting the beginning of time which indeed contradicts of saying time is relative in the first place. I think we simply haven't really answer what was in the "beginning of times" as on one hand "everything flows" and matter and energy could not just be in a frozen initial state and on the other hand we don't have an indication that our universe has a circular story where the Big Bang would be repeated as we just see the universe expanding. It is still an open and interesting question to be answered.

Quote:

---

Originally Posted by C_ntua

There has to be something before the Big Bang as otherwise we are just "conveniently" setting the beginning of time which indeed contradicts of saying time is relative in the first place. I think we simply haven't really answer what was in the "beginning of times" as on one hand "everything flows" and matter and energy could not just be in a frozen initial state and on the other hand we don't have an indication that our universe has a circular story where the Big Bang would be repeated as we just see the universe expanding. It is still an open and interesting question to be answered.

---

God :p

But speaking of a First Cause, Yarin seems to have anticipated your point with the assertion that:

Quote:

---

Originally Posted by Yarin

The philosophy that the Big Bang is the first cause is superfluous to the relativity of space.

---

at least treating "space" to mean "space-time".

Quote:

---

Originally Posted by C_ntua

There has to be something before the Big Bang as otherwise we are just "conveniently" setting the beginning of time which indeed contradicts of saying time is relative in the first place.

---

We just don't know. There's the theory of a pulsating universe; growing, eventually loosing momentum and contracting back to a singularity, at which point a new Big Bang takes place. We seem to agree all the laws of physics break down at the moment of the Singularity. Space-time breaks down and we lose any meaning for terms like "before" or "here". They just don't exist anymore. It's just not that we won't ever be able to prove their existence, study, observe or even extrapolate. It's that in fact that moment and that place before the Big Bang never existed. A Big Bang is, for better or worse, the real beginning. One just has to accept a theory without its implications.

It's important to reinstate that a pulsating universe can never be proved. The laws of physics make it impossible for us to do so. We can only eventually one day observe a universe collapsing, but our calculations can only put us close to an eventual singularity.

(EDIT in the shape of a PS)

An analogy can be made (carefully) with the idea of self-awareness. The moment at which you gained your idea of Self. When was this exactly? You cannot ever measure it precisely. It is lost because your brain never registered the moment it turn that aspect on or it did so in a time where there were no active receptors to store it. And more importantly, was there ever a "You" before You?

Do not be tempted to gain refuge in future science. We may reach a moment when one day all answers to the mystery of self-awareness will be reached. But this is so only because we benefit from an advantaged observation. We can observe others. As if an observer in another universe could study us and our universe. But were you living all your life in isolation in a cave, you would in fact properly emulate our universe boundaries in terms of what knowledge you could gain of your self-awareness. Regardless if you lived 90 years or a billions years, you would only be able to contemplate that you had a beginning, not sure when or how, and there was no time before you.

I find this thread very interesting, since relativity has always been my favourite physics problem :D

I know that my knowledge is very limited (through I must admit to have been reading and thinking on this subject much), but nonetheless, I would like to share my understanding as a young person. I will purposedly be using "I know, I should" instead of "we know, we should". And I am sorry if I am ignorant.

The thing I know is that there are at least 4 dimensions. The first three are spatial and the other one is time, all four forming a space-time. As far as I know, I should be looking everywhere for patterns and common features, and generally try to treat everything in a uniform manner. If so, this means that I should not differentiate dimensions into spatial [x,y,z], time [t], and others like let's say atomic-level (or whatever I heard of) [w1,w2,w3] etc. These all dimensions have common properties, and the only difference is that I percieve them differently. I percieve them differently because, e.g., [x,y,z] change slower for objects which surround me than [t]. Light moves at zero speed in the 4-th dimension [t], but with maximum speed in [x,y,z], unlike me who move with almost maximum speed in [t] and almost zero speed in [x,y,z]. This makes me think to treat all dimensions in a uniform manner, no matter how many there are.

Now I would like to create a universe equation. I have several possibilities. The most obvious one for a human being like me is to associate the function's variable with [t]:
1. fy = f(t)
This function returns all particles (and so forth) and their coordinates at the specified time point. This is the most obvious one, because as the time elapses things move and interact.
2. fy = f(x)
This one does the same, except that it accepts x as an argument. It is pretty hard to visualise through.
3. fy = f(y,t)
Or any combination as above.

The problem with my approach is that it seems to be introducing a global reference point, meaning that relativity does not exist for God who knows this function.

Having defined a function, do I really need to simulate it? What would be that simulation?

I have a function y=x^3 and this function just exists - exists in theory. If I want to check what is the value at x = -1000, I do a substitution. If I want to check what is the value 2,3,n units before that x, I just do a substitution. And my understanding of a universe (which changes everyday...) is something like this. If I want to know what happened at t = <some_t>, I substitute and get all possible coordinates of all possible information. If I want to know what happened before big bang, I need to substitute [t] to the equation and I will get the result. So I did not have to simulate it in a continuous form from the beginning of f(-inf) at all. It just exists for me as y=x^3 does for x = -1000.

The problem with my understanding is that I do not know whether I introduce a global reference point or not. I do if I have a reference state, like f(0), but I do not if this function does not have a reference state like y=x^3 does not. However, the function itself is defined in some way, so some information is somewhat globally predefined. I could use infinite recursion, not introducing any state, but this one seems impossible because it would require continuous simulation from the beginning. In any case such my function would allow my universe to be non-circular (not a "pulsating universe" as somebody before said?), and could be either discrete or continuous.

In other words, I imagine that God invented such a function, together with perception and ability to differentiate time from space. I know it does not make much sense through... ;)

Hey, I was meant to be getting back to something constructive like reading
through a zillion pages of Linux documentation, and instead I'm dragged back into
metaphysical speculation and even G. O. D.?:rolleyes::)

Anyway, what I was saying is that IF the big bang theory is correct ( currently its
known as the Standard Model and all observational data is generally talked about
with reference to it e.g. the recent discovery that the expansion is continuing to
accelerate.) and if it reaches a good degree of precision they will have found the
reference frame in which an observer would be accelerating in sync with the general
expansion.There is only ONE reference frame in which this would be true in space and
time.

This reference frame would thus be a kind of absolute frame of reference throughout
the Universe.

In a static universe no such reference would exist.

Whereas to talk about before the big bang or 'outside' the universe would be the realm of
metaphysics - it would be trying to talk about a 'different reality' entirely maybe.

For example 'before the big bang' would effectively be to talk about before or beyond
time which is the definition of 'eternity', and notions of non-existance as opposed to
existance which as Mario wrote also have parallels with our own individual lives.

As the Nasadiya Creation Hymn from the Rig Veda says ' who really knows?'.

(Not that I'm recommending the Rig Veda or anything, it's just one short interesting passage.)

Of course, the other Big Bang is Life itself.

And what life is, is still another really biggy science has yet to answer as well.

So we have 2 mysterious big bangs.

As for God, well, we all know he sits on a cloud in front of a control panel with thousands
of buttons,pulleys and levers and if we pray hard enough he will give us next weeks lottery
money.

Quote:

---

Originally Posted by laserlight

God :p

---

I actually find it quite interesting how these questions are combined with other believes people have, religious being the most significant one. It gives an expectation to people, that what we will find in science will align with what their religion believes. If you believe that the God of thunder is the only one creating lighting then you are probably disappointed to see it being a natural phenomenon. If your God was a one of Time, Einstein maybe is your favorite person (or your worst).

Quote:

---

Originally Posted by Yarin

The philosophy that the Big Bang is the first cause is superfluous to the relativity of space.

---

Quote:

---

Originally Posted by C_ntua

There has to be something before the Big Bang as otherwise we are just "conveniently" setting the beginning of time which indeed

contradicts of saying time is relative in the first place. I think we simply haven't really answer what was in the "beginning of times"

as on one hand "everything flows" and matter and energy could not just be in a frozen initial state and on the other hand we don't

have an indication that our universe has a circular story where the Big Bang would be repeated as we just see the universe

expanding. It is still an open and interesting question to be answered.

---

Those were in response to this:

"That is what I would disagree with. In my understanding of relativistic space, there is nothing outside our universe,
nor was there ever anything outside of it. There was nothing here at all until the "explosion" of the cosmic egg. And
then there was only what was in the "sphere" of the expanding universe" - me

I should have been clearer. The only point was that there is nothing outside the universe as we know it,
and there was nothing here before the Big Bang in the form of spacetime as we know it. That was all in
relation to relativistic reference frames. I would imagine that the "cosmic egg" itself was here at least,
immediately before the Big Bang.
So not the first cause, just the origin of spacetime.

Quote:

---

Originally Posted by gemera

Anyway, what I was saying is that IF the big bang theory is correct ( currently its
known as the Standard Model and all observational data is generally talked about
with reference to it e.g. the recent discovery that the expansion is continuing to
accelerate.) and if it reaches a good degree of precision they will have found the
reference frame in which an observer would be accelerating in sync with the general
expansion.There is only ONE reference frame in which this would be true in space and
time.

---

Wouldn't accelerating expansion still be relative? Wouldn't every point be accelerating away from every other point
in the same way?

Also, we can measure accelerating forces, like we experience just standing here on the earth, or the centrifugal
forces of the rotating earth. But this in itself doesn't indicate motion (Einstein's Elevator and Newton's Bucket).
Some will argue that there is no physical test that you can perform to indicate whether your experienced effects
are due to acceleration through space or gravity. This has nothing to due with the likelyhood of one or the other
being correct, just that both are equally valid.

It's intrinsic to the big bang theory that you can model the Universe
and that observation can be married with theory.

So the field equations are used to form a mathematically non-extrapolated
4d Riemannian universe. This riemannian equation describes a reference frame
in which an observer is accelerating in sync with the expansion.

All I'm saying is that if it is true it can be modelled then it would represent
a default absolute in the sense that intelligent cosmologists all over the universe
should agree on this model and thus this reference frame. This follows directly as
a consequence of the theory.

And whereas the expansion is only apparent on the large scale such that, for example,
our local cluster of galaxies take part in the expansion as a group, I would agree
that as an actual absolute against which ALL motion could be referenced, things might be
more problematic.

Ok, that's interesting.

Would that also imply an absolute center of the universe?
Would such a space be non-isotropic?

Well its been a while since I looked at this stuff, and I'm certainly no
expert, so you're probably better off googling for the minutae.

I mean, I have always taken the text book line that there was no universally
agreeable reference frame up until reading your piece when this 'irritant' thought
entered, so I'm still wondering what it means exactly, if anything.

I would think in a closed system a reference that different parts of
the system can agree on would normally be an absolute for that system.

But it may be in this case that whereas there can be agreement on the
model/reference it has no use beyond that.

So its some kind of Non-absolute Absolute.

Maybe.

Any cosmologists about?:)

Quote:

---

Originally Posted by megafiddle

I should have been clearer. The only point was that there is nothing outside the universe as we know it,
and there was nothing here before the Big Bang in the form of spacetime as we know it. That was all in
relation to relativistic reference frames. I would imagine that the "cosmic egg" itself was here at least,
immediately before the Big Bang.
So not the first cause, just the origin of spacetime.

---

There are actually theories that go beyond the Big Bang theory. There are also 3 known problems with the theory as it is where you need to expand it to solve. The string theory attempts for example to give a more complete picture, though I haven't ever studied it to comprehend it.

One thing I don't fully comprehend with relativity is why do we choose to consider space and time relative but not speed. For example, if I talk about curves in spacetime I am basically saying that it curves compared to an "imaginary" 3-dimensional space. When I say that two reference points will see a different sequence of events I am using an "imaginary" absolute time where I could take two snapshots that would be different. All I know really is that if you are in motion using the same measuring devices we will end up with different results. We assume that the measuring devices are not affected thus we need to change how we view space, speed and time but I don't comprehend why we cannot just say that the measuring devices function in a specific way, meaning that the speed of light is not constant in that sense. Then we can keep the space 3-dimensional as well as the time absolute which at least to me feels more solid as modelizing the world just because I can understand it better.

If the speed of light is not constant that means that other laws become relative in that sense. For example, if we measure the time using the frequency of atoms that would mean that motion affects their frequency or motion would affect electromagnetic waves, which is something that we say is not true. Yet mathematically speaking you can say it is if you were to keep time itself linear. The difference is really how you imagine it and for me it is easier to say that motion affects matter in a fundamental way rather than changing the way I view time and space.

Quote:

---

Originally Posted by C_ntua

One thing I don't fully comprehend with relativity is why do we choose to consider space and time relative but not speed.

---

Oh, but speed is relative. To an external observer someone walking inside a train in the direction the train is moving, is walking at a different speed than to any observer inside the train.

I don't fully comprehend the rest of your reasoning and you may need to clarify.

Quote:

---

Originally Posted by Mario F.

Oh, but speed is relative. To an external observer someone walking inside a train in the direction the train is moving, is walking at a different speed than to any observer inside the train.

I don't fully comprehend the rest of your reasoning and you may need to clarify.

---

I wasn't indeed very clear. My point was to say that there are two parts in a theory like SR. One is the mathematical part where you can use to predict motion and the other part is how that changes the way we view the world. I believe that SR does an excellent job on the first, but doesn't help us for the second. The impact of this is that we might not get what we think we will get.

Let me go to the twins paradox again. Let me change it saying that the twin returns to earth and he looks exactly the same as his brother (we cannot prove yet if this is true or not), but the atomic clock in his spaceship shows something different. The question is if time slowed down in which the answer would depends on what do you define as time. If it is related to aging then time didn't slow down. If it is how the atomic clock measured it would (according to SR). At the end of the day both have to do on the effect of acceleration in atoms which we have trouble measuring anyway according to the uncertainty principle. The assumption is that time affects all atoms the same way, since it affects the clock it would affect the body. But "time" is really an abstract idea and with SR it is even relative. So instead of saying that acceleration affects time and time affects the body, you can say that acceleration affects the body itself, every atom of the body. The same can be said for speed. Instead of saying that space contracts or expands you can say that matter went faster or slower and that is what is what I meant that speed is relative or "more" relative including the speed of light.

I am not implying that SR is wrong, even if you think of matter fundamentally changing still the end result is the same and the differences are between different frames. But it is just a matter of how we view time and space and I don't think we can view them differently as we "normally" do. So spacetime can have a mathematical meaning but it is really not space and time the way we imagine it and somehow "overriding" the terms of space and time creates more confusion.

On the other hand we can imagine a clock going slower or faster easily. The reason is that we envision time using an "imaginary and absolute" clock. If we were to view a clock going slower it would be slower compared to our imaginary clock. If now we take the faster clock it would go faster compared to the imaginary clock. In both cases we assume of course that the imaginary clock stays the same.
If we want to imagine one twin aging slower then we would need to take a snapshot from both. SR shows there is no simultaneity. Yet there is no other way imaging it. This implies again that time is not relative, not in the way we actually imagine it. That is also what I meant of the spacetime having curves as a curve by itself means nothing if you cannot compare it with a straight line. So we put the "real" spacetime in an imaginary space which is in its sense 3D space not being affected by motion. Now if we were to use pure Newtonian laws then it seems that we can imagine things as we describe them. Time is the same as our imaginary time and space is the same as our imaginary space. You can say that this is due to the complexity, but my point is that you there is a certain way you will imagine or modelize them. So instead of trying to make a complex model or a complex explanation on how space and time is we can just describe the laws in a more complex way. When you put everything together you still have the same result regardless the model chosen.

(I am not sure I make sense anymore...)

Ah, I see your point now.

Well, Special Relativity was the beginning of a "new wave" of science that will invariably make our universe harder and harder to understand. Possibly for the simple reason its just the way it really is. Our understand of that which surrounds us has no doubt reached a threshold in which it no longer needs to concern itself with basic explanations meant for a practical life. I know i'm stretching it because there's still many things we need to discover, but I think you get my meaning.

And that is; On our quest for knowledge of the Cosmos (all things that are, were, and will ever be, from the smallest to the largest) we obviously are overshooting our still young and undeveloped human brain cognitive capacities. Most of the modern science today needs to be explained in all manner of tropes (analogies, hyperbole, anthropomorphism, parables, paradoxes, etc). In fact many of the things we have discovered in the past have evolved themselves into radically more complex entities that are hard to understand in modern science. The atom is a notorious example. It's cloud-like shape has evolved from the simpler orbiting electron form, but we know that even that is a gross representation of an object we cannot comprehend in the physical reality we inhabit.

And let's not even get into quantum mechanics.

But the important thing to retain about the Twins Paradox and other similar constructs is that they aren't real science. They are Thought Experiments meant to expose a complex scientific concept that can only be fully understood in the closed world of mathematical calculations. Let me make this perfectly clear: The Twins Paradox is not science. It's a way to convey science. It opens the mind for initiates to the actual science that will take place in its only possible domain; mathematics. And it can often also help convey science to the untrained. For this reason, the Twins Paradox and other constructs are potentially ripe with... I wouldn't call it inaccuracy, but are clearly loose in the way they describe a concept that can only be described in a mathematical format.

A true representation of a superior intellect has always been in my mind that of a being capable of having full cognitive understanding of a physical reality that isn't in the same domain/dimension where his senses inhabit. In that regard, we humans are lesser beings. Mere nothings in our ability to perceive the physical reality of our universe. Mathematics have been our greatest achievement so far in that evolutionary process. But that stands to reason being us so young in the universe.

Quote:

---

Originally Posted by Mario F.

A true representation of a superior intellect has always been in my mind that of a being capable of having full cognitive understanding of a physical reality that isn't in the same domain/dimension where his senses inhabit. In that regard, we humans are lesser beings. Mere nothings in our ability to perceive the physical reality of our universe. Mathematics have been our greatest achievement so far in that evolutionary process. But that stands to reason being us so young in the universe.

---

That is very well phrased!

Quote:

---

Originally Posted by Mario F.

A true representation of a superior intellect has always been in my mind that of a being capable of having full cognitive understanding of a physical reality that isn't in the same domain/dimension where his senses inhabit.

---

I'm inclined to say that description can't exist, as that sounds like it would violate cognitive closure.

Quote:

---

Originally Posted by Yarin

I'm inclined to say that description can't exist, as that sounds like it would violate cognitive closure.

---

That concept is merely an untested (it didn't pass the rational method) philosophical proposition. It also completely ignores evolution and what it can possibly offer in a few million years to a surviving intelligent species. Being a philosophical proposition it also can't be proposed as a law, much less one that can't be violated.

Let's leave philosophy (which I adore, mind you) to those areas where its relationship with science can be useful.

Quote:

---

Originally Posted by Mario F.

A true representation of a superior intellect has always been in my mind that of a being capable of having full cognitive understanding of a physical reality that isn't in the same domain/dimension where his senses inhabit. In that regard, we humans are lesser beings. Mere nothings in our ability to perceive the physical reality of our universe. Mathematics have been our greatest achievement so far in that evolutionary process. But that stands to reason being us so young in the universe.

---

Measuring yourself or humanity by a gross idealisation which has no basis in reality
is a sure-fire way to give yourself or humanity a negative characterisation with no
basis in reality.

At some point you missed the point.

Quote:

---

Originally Posted by Mario F.

And that is; On our quest for knowledge of the Cosmos (all things that are, were, and will ever be, from

the smallest to the largest) we obviously are overshooting our still young and undeveloped human brain cognitive capacities. Most

of the modern science today needs to be explained in all manner of tropes (analogies, hyperbole, anthropomorphism, parables,

paradoxes, etc). In fact many of the things we have discovered in the past have evolved themselves into radically more complex

entities that are hard to understand in modern science. The atom is a notorious example. It's cloud-like shape has evolved from

the simpler orbiting electron form, but we know that even that is a gross representation of an object we cannot comprehend in the

physical reality we inhabit.

---

I think physics doesn't so much describe the physical world as it describes our model of it. Every once in a while,
experimental physics throws a monkey wrench into the model and we wind up with a new or revised model. Maxwell's
electromagnetic field equations did just this. Often it gives us more new things to explain than it answers.

Quote:

---

Originally Posted by Mario F.

But the important thing to retain about the Twins Paradox and other similar constructs is that they

aren't real science. They are Thought Experiments meant to expose a complex scientific concept that can only be fully understood

in the closed world of mathematical calculations. Let me make this perfectly clear: The Twins Paradox is not science. It's a way to

convey science. It opens the mind for initiates to the actual science that will take place in its only possible domain; mathematics.

And it can often also help convey science to the untrained. For this reason, the Twins Paradox and other constructs are potentially

ripe with... I wouldn't call it inaccuracy, but are clearly loose in the way they describe a concept that can only be described in a

mathematical format.

---

The "twin paradox" may not be science in the usual sense (providing an experimental result), but Thought Experiments
are science. A Thought Experiment has some serious requirements. It must be based on accepted laws of physics; it
cannot violate any. It needs to obvious or at least determinable that the Thought Experiment would proceed exactly as
the real experiment would, if it could be performed. A Thought Experiment is used where the actual experiment would
be impossible for practical or technical reasons.

It was partly the simplicity of Einstein's "bouncing photon clock" that was responsible for it's wide acceptance. It involved
nothing more than the Principle of Relativity (relative motion) and the observed constancy of light speed (both of these
principles were already widely accepted, but at odds with each other). The experimental results of that Thought Experiment
became the Special Theory of Relativity.

But to answer your original question, "...To that end we say that the travelling twin experienced acceleration. But what exactly

experienced acceleration?

I'm not interested in the paradox per se. What I'm interested in understanding is exactly what force allows for a system (the

travelling twin, for instance) to be considered a single unit and to experience the effect of time dilation as a whole...",

There are two aspects of the time dilation effect. One of these is described by Special Relativity and is what I would
call nonpersistant. These effects do not persist when the two clocks are reunited and compared. The effect only
exists while the clocks are observed in motion relative to each other. My "symmetrically orbiting twins" thought experiment
in an earlier post illustrates this.
This aspect of time dilation is a matter of perspective, it is how the universe appears to an observer in relative motion.
But the concept of an observed effect should not be mistaken for an illusion. Observation is the same concept as used in
performing any experiment and evaluating the results. It is not just what we see; it is physical reality in the same sense as
any other experimental observation. When the "stationary" and "travelling" clocks are reunited, the relative motion is no longer
there, and neither is the time dilation. The perspective view of spacetime is now different.

The other aspect of time dilation is described by General Relativity, and is what I would call persistant. When reunited
and compared, the clocks will show an elapsed time discrepency. The travelling twin does indeed experience a force, an
accelerating force, although I'm not sure that it is a force in the same sense that you meant it.

If an object is falling above a planet, it experiences no force. Yet it accelerates. The reason is that the force is distributed
evenly (ignoring tidal force) among the entire mass of the object. There is nothing resisting the acceleration. If the object
is sitting on the surface of the planet, however, the surface is resisting the accelerating force. So the object experiences
weight. In the case of an object sitting on a gravitational mass, or an object being accelerating through space, both
experience accelerating forces and both experience persistant time dilation.

However, I think the accelerating force is not the cause of time dilation, but just another effect of being within a curved
section of spacetime. It is the curvature that causes the accelerating force. And it is within this curvature that time
progresses more slowly.

Quote:

---

Originally Posted by megafiddle

I think physics doesn't so much describe the physical world as it describes our model of it. Every once in a while,
experimental physics throws a monkey wrench into the model and we wind up with a new or revised model. Maxwell's
electromagnetic field equations did just this. Often it gives us more new things to explain than it answers.

---

I'm not sure what a model may mean in this context(*), but Physics strives to make us understand how the universe behaves. It's really a wide-encompassing field, full of complexity, but really easy to generally describe. There's no mystery to its purpose. No second meaning either.

The trouble is that the universe has been consistently shown to exist and behave in ways that transcend our senses -- lately, also our cognitive abilities to understand it.

It's easy to come up with false color images to show light in all its variety, considering the greatly limited band our eyes can perceive. But its a first step to understand how our universe exists in domains that exceed our senses. Other physical realities are however much harder to model and may never have a proper representation. While an atom can be exactly represented as a mathematical entity (a mathematical model if you may), it probably will forever be beyond our sensory and cognitive capacities to come up with a visual entity that better describes it. Exactly because it exists in a "place" outside that domain.

Meanwhile we have been developing scientific fields that go well beyond these limitations and into newer areas that completely challenge our cognitive abilities. Quantum Theory is such a branch of physics, in which men like Heisenberg, Bohr, Schrodinger and Feynman have been known to openly and gladly admit we cannot understand it. The science is way beyond our available tools to explain it. Even Thought Experiments show their limitations when it comes to explaining its theories. And yet, Quantum Physics, despite its almost wizardly reputation, has been consistently shown to produce sound theories that stand peer review and have been proven consistent over and over again. It seems to be true than that the universe exists and behaves too on a level well beyond our ability to properly understand it.

So.. my earlier post (and this one as an extension to that) was all in reply to C_ntua justifiable annoyance that later branches of physics have been consistently introducing into our understanding of the universe a reality that is becoming harder and harder to understand. That is so because the universe really exists beyond our capacity to fully understand it. It's not terrible, shouldn't be heart breaking, and it's not humiliating, to assume that we may need to climb a few more steps in the evolutionary ladder to better understand our universe. The progression of Science is deeply tied to our evolutionary pattern. Has in the past and will be in the future.

Quote:

---

Originally Posted by megafiddle

The "twin paradox" may not be science in the usual sense (providing an experimental result), but Thought Experiments
are science. A Thought Experiment has some serious requirements. It must be based on accepted laws of physics; it
cannot violate any. It needs to obvious or at least determinable that the Thought Experiment would proceed exactly as
the real experiment would, if it could be performed. A Thought Experiment is used where the actual experiment would
be impossible for practical or technical reasons.

---

Again, no. Thought Experiments aren't science! Really, we need to get that right. It's a dangerous road that one with the potential to damage even more the already shaken credibility of science in the public eye.

Thought Experiments.

Quote:

---

Originally Posted by megafiddle

It was partly the simplicity of Einstein's "bouncing photon clock" that was responsible for it's wide acceptance. It involved
nothing more than the Principle of Relativity (relative motion) and the observed constancy of light speed (both of these
principles were already widely accepted, but at odds with each other). The experimental results of that Thought Experiment
became the Special Theory of Relativity.

---

This says nothing about the actual science that took place to properly demonstrate the theory. The thought experiment was simply a verbal device that helped producing a scientific theory, because there was no way at the time to properly apply the scientific method. The theory was accepted, but put on hold until properly demonstrated. Thought experiments can certainly end up producing new theories. But in themselves they are nothing more than an exercise of the Rational Method, not the Scientific Method.

I agree with Mario F

The scientific method uses both Deductive Logic and Inductive Reasoning.

Deductive Logic starts with one or more premises -> Things that the researcher assumes is true

"Gumtrees are Plants" (premise 1)
"All plants produce energy through photosynthesis" (premise 2)
"Then Gumtrees must produce energy through photosynthesis" (conclusion)

If one of these premises are false, then all post conclusions are compromised - "The world is flat" is often a good example of this.

Inductive Reasoning is based on what has been observed to draw conclusions about things. This is usually done by experiments and measuring the outcomes of the experiments. For example: 100% of my peanut-butter on toast fell on the floor peanut-butter side down; therefore it is likely to always fall that side down.

The Scientific Method requires a defined problem, a hypothesis (which if confirmed, solved the problem), gathering of data, and analysing the data to see whether it supported the hypothesis or not.

A hypothesis from the peanut butter experiment may be that one side of the bread may be heavier ->
"When things fall, the heavier side will orientate itself closer to the ground"
"The Peanut-Butter side is heavier"
"When the Peanut-Butter on toast falls to the ground, the Peanut-Butter side will orientate itself closer to the ground"

However, marking both sides with coloured pens (making the colours different to tell the different sides apart, whilst keeping the weight equal) will debunk this hypothesis - It's because there is a problem with the first premise.


Without experimental results supporting your Hypothesis, you have a chance of being wrong - And if someone else uses your assumption to build another assumption... well...

I would agree that Thought Experiments are not scientific method, and are not an scientific experimment.

But it seems they can be scientifically valid, if properly constructed. Even physical experiments require
logic and reasoning to arrive at a result. If no additional data or facts are required, beyond what is already
given, then shouldn't logic and reasoning provide a scientifically valid result?

Are you asking if all Deductive Logic premises are backed up with Inductive Reasoning - Is the result valid?

I don't believe that this is always true, because there could be another reason for an experiment agreeing with the hypothesis that the person conducting the initial research didn't think of.

The actual reason for the toast always landing spread side down is usually put down to the hight of the table -> If the experiment was conducted on a different sized table, the data may accidentally support a wrong hypothesis (When I removed the weight from one side, the landing orientation became unpredictable: Therefore, the reason the toast always lands spread down is because of one side being heavier than the other)

Quote:

---

Originally Posted by megafiddle

But it seems they can be scientifically valid, if properly constructed. Even physical experiments require
logic and reasoning to arrive at a result. If no additional data or facts are required, beyond what is already
given, then shouldn't logic and reasoning provide a scientifically valid result?

---

That is akin to applying a Rational Method (Rational Argument, as known to philosophy) to science. It can't do.

Not at least in the context of Thought Experiments. Because they make no concessions to the natural laws. A Thought Experiment is only scientific valid in its logical domain and exists only as a logical abstraction. It won't be valid anywhere else. Demons don't really exist (apparently) that can manipulate machinery at the speed of light, a cat cannot be confirmed to both dead and alive, an athlete carrying a pole cannot run at the speed of light. This may or may not have an effect on the validity of a Thought Experiment as a source for a scientific result. While Albert Einstein was able to successfully develop a theory through a Thought Experiment, he was also able to be proven completely wrong with another; on his infamous EPR paper.

I would argue that we can successfully apply logic and reasoning while analyzing a scientific result. That will do. And its been sorely lacking on many of our universities and what students and their teachers have been doing with their grants. Studying 100 random people, no matter how valid is the scientific method applied, does not make the result necessarily universal to the human race. There's been an overabundance of statistics and very little science in many of our universities. At least judging by the media.

Quote:

---

Originally Posted by Click_here

Are you asking if all Deductive Logic premises are backed up with Inductive Reasoning - Is the result valid?

I don't believe that this is always true, because there could be another reason for an experiment agreeing with the hypothesis that the person conducting the initial research didn't think of.

---

But isn't that also true with a physical experiment?

Quote:

---

Originally Posted by Mario F.

That is akin to applying a Rational Method (Rational Argument, as known to philosophy) to science. It can't do.

Not at least in the context of Thought Experiments. Because they make no concessions to the natural laws. A Thought Experiment is only scientific valid in its logical domain and exists only as a logical abstraction. It won't be valid anywhere else. Demons don't really exist (apparently) that can manipulate machinery at the speed of light, a cat cannot be confirmed to both dead and alive, an athlete carrying a pole cannot run at the speed of light. This may or may not have an effect on the validity of a Thought Experiment as a source for a scientific result. While Albert Einstein was able to successfully develop a theory through a Thought Experiment, he was also able to be proven completely wrong with another; on his infamous EPR paper.

I would argue that we can successfully apply logic and reasoning while analyzing a scientific result. That will do. And its been sorely lacking on many of our universities and what students and their teachers have been doing with their grants. Studying 100 random people, no matter how valid is the scientific method applied, does not make the result necessarily universal to the human race. There's been an overabundance of statistics and very little science in many of our universities. At least judging by the media.

---

Is it possible to construct a thought experiment that is so simple, that the result would be accepted a priori as scientific fact?

A Thought Experiment is a Hypothesis - Nothing more. And a Hypothesis is not a scientific fact.

"scientific fact" from Dictionary.com
"Definition: Any observation that has been repeatedly confirmed and accepted as true; any scientific observation that has not been refuted"

You build your Hypothesis from Scientific Fact, but it in itself does not become Scientific Fact until it can predict an observation in the real world.

The movie "The Matrix" has a very convincing argument. In fact, there would be a lot of Sci-fi which could be roped in as arguments logically put forward - But none of them Scientific Fact.

Quote:

---

Originally Posted by Mario F.

That concept is merely an untested (it didn't pass the rational method) philosophical proposition.

---

It's an observed concept. I imagine trying to test it would produce far less promising results than said simple observation of it. This seems to hold true for any stance on qualia.

Quote:

---

Originally Posted by Mario F.

It also completely ignores evolution and what it can possibly offer in a few million years to a surviving intelligent species.

---

Even if the evolution you speak of was true, closure would still hold true because said evolution isn't driven by ourselves.

Quote:

---

Originally Posted by Mario F.

Being a philosophical proposition it also can't be proposed as a law, much less one that can't be violated.

---

When unwound, all reason will eventually fall on to "philosophical propositions", so labelling my argument as such is not sufficient reason to dismiss it.

Quote:

---

Originally Posted by megafiddle

But isn't that also true with a physical experiment?

---

For sure. Science usually advances by debunking old theories.

But a thought experiment doesn't offer any mechanisms to be tested through another thought experiment. It is a construction that is purposely made valid according to available knowledge. As such, in its time, it is always true and never false. What will determine its falsehood is new knowledge gained from hard science. A scientific theory, on the contrary, requires will be evolved or debunked through another scientific theory. The scientific method is built to oversee itself.

Quote:

---

Originally Posted by megafiddle

Is it possible to construct a thought experiment that is so simple, that the result would be accepted a priori as scientific fact?

---

Such a thought experiment would be unnecessary. What manner of new scientific knowledge could we gain from a simple logical device? If something new is so obviously true, then we don't need an abstraction to test and validate it. It just is true by sheer deduction.

Quote:

---

Is it possible to construct a thought experiment that is so simple, that the result would be accepted a priori as scientific fact?

---

Can you give us an example?

[edit]
I should add that I'm after a new scientific fact, not just establishing that your "thought experiment" is a variation of another scientific fact.
[/edit]

Quote:

---

Originally Posted by Yarin

It's an observed concept. I imagine trying to test it would produce far less promising results than said simple observation of it. This seems to hold true for any stance on qualia.

---

Right. The God theory. You cannot prove it false, so it must be true.

Anyways, no it is not an observed concept. It can only be partially observed and because of the very nature of its formulation, cannot be proven true. Cognitive Closure is an absolute nonsense that has the good sense of remaining to this day a philosophical hypothesis. Check your facts.

Quote:

---

Originally Posted by Yarin

Even if the evolution you speak of was true, closure would still hold true because said evolution isn't driven by ourselves.

---

And who by then? Nature (whatever It may be)? God? Aliens?

Evolution is strictly dictated by ourselves. I suggest, if Charles Darwin is too complicated of a reading, you read Mount Improbable by Richard Dawkins, author of The Selfish Gene. An even better reading, but more difficult.

As for the evolution I speak of being true or not, I'm assuming you are not a Creationist and you just referring to the fact we may not evolve in the direction I wished.

Well, there's very little doubt in my mind that one of the organs in our body that has a whole lot more evolving to do is precisely our brain. Unless you think we reached the pinnacle of our species. Personally I think we haven't seen even the beginning of it.

Quote:

---

Originally Posted by Yarin

When unwound, all reason will eventually fall on to "philosophical propositions", so labelling my argument as such is not sufficient reason to dismiss it.

---

Let's avoid unwinding too much then.

Quote:

---

Originally Posted by Mario F.

You cannot prove it false, so it must be true.

---

I never said this. Strange that you make this a false dilemma.

Quote:

---

Originally Posted by Mario F.

It can only be partially observed and because of the very nature of its formulation, cannot be proven true.

---

Well, it's been proven that not all truths can be proven.
I tend to believe things when I have good reason to, even if not proven (in the purest sense of the word).

Quote:

---

Originally Posted by Mario F.

Cognitive Closure is an absolute nonsense that has the good sense of remaining to this day a philosophical hypothesis. Check your facts.

---

Your opinion. I may just as easily tell you to "check your facts".

Quote:

---

Originally Posted by Click_here

A Thought Experiment is a Hypothesis - Nothing more. And a Hypothesis is not a scientific fact.

"scientific fact" from Dictionary.com
"Definition: Any observation that has been repeatedly confirmed and accepted as true; any scientific observation that has not been refuted"

You build your Hypothesis from Scientific Fact, but it in itself does not become Scientific Fact until it can predict an observation in the real world.

---

As formally defined, the results of a thought experiment would not be accepted as scientific fact.
But isn't it just a matter of confidence that makes the scientific method an acceptable source of fact?
Isn't scientific method also a test of the reasonong that formed the hypothesis and designed the experiment?
And isn't the result meaningless unless the reasoning itself was valid to begin with?

What I am wondering is if scientific method just has a higher level of confidence in the result because of the physical result,
but not only because of the physical result. Wouldn't it be the combined weight of both reasoning and physical result, and
not necessarily the presence of both.

I'm not arguing with the meaning of "scientific method". It is as it is defined.

Quote:

---

Originally Posted by Mario F.

But a thought experiment doesn't offer any mechanisms to be tested through another thought experiment. It is a construction that is purposely made valid according to available knowledge. As such, in its
time, it is always true and never false. What will determine its falsehood is new knowledge gained from hard science. A scientific theory, on the contrary, requires will be evolved or debunked through another scientific theory. The
scientific method is built to oversee itself.

---

Some thought experiments are just imagined scenarios based on accepted fact or theories. The "twin paradox" was not intended as a proof of time dilation.
It only demonstrates the difference between inertial and noninertial effects.
Is this what you are referring to, or would you say that it also applies to an "experiment" where one or more facts are the basis, and a separate result is being derived?

Referring to my question - "Is it possible to construct a thought experiment that is so simple, that the result would be accepted a priori as scientific fact? "

Quote:

---

Originally Posted by Mario F.

Such a thought experiment would be unnecessary. What manner of new scientific knowledge could we gain from a simple logical device? If something new is so obviously true, then we don't need an
abstraction to test and validate it. It just is true by sheer deduction.

---

But isn't that a matter of degree, not of principle?

Quote:

---

Originally Posted by Click_here

Can you give us an example?

[edit]
I should add that I'm after a new scientific fact, not just establishing that your "thought experiment" is a variation of another scientific fact.
[/edit]

---

No, I wish I had one. But I will use the "bouncing photon clock" just to illustrate what I mean by "a thought experiment that is so simple".

The "experiment" is based on just three quantities, length, time, and velocity. Also it is based on just two scientific facts or principles, motion is relative,
and the velocity of light is constant for all observers.

It just seems that the following must be true:

The photon in the moving clock must travel a longer path between clock "ticks".
The photon must travel at the same velocity in the travelling clock as it does in the stationary (reference frame) clock.
Time = Distance / Velocity; therefore if distance increases, then time increases (time has slowed).

I would imagine though, that another thought experiment could just as well be a valid refutation, if one exists.

Quote:

---

Originally Posted by megafiddle

But isn't that a matter of degree, not of principle?

---

It's definitely a matter of principle where grade pays a role. If there is no reason to construct a Thought Experiment because the formulation is so simple it can be understood by mere reasoning, a Thought Experiment is just redundant and pedantic.

Quote:

---

Originally Posted by megafiddle

Some thought experiments are just imagined scenarios based on accepted fact or theories. The "twin paradox" was not intended as a proof of time dilation.
It only demonstrates the difference between inertial and noninertial effects.
Is this what you are referring to, or would you say that it also applies to an "experiment" where one or more facts are the basis, and a separate result is being derived?

---

It applies to Science as a whole. A Thought Experiment, when used as a means to construct a new theory, as was the case with Special Relativity (not entirely accurate, but lets leave it that way), does not constitute proof of any kind. Thought Experiments are not a scientific device. I really can't stress this any further. Special Relativity has its own experimental basis. This is the true device of science and the one that validated SR as a theory.

So a bouncing photon clock thought experiment that tries to demonstrate the possibility of time dilation, as simple as it may sound, cannot evolve from that formulation without being experimentally sound. It's at that point that it can constitute a true scientific theory. In isolation, without any application of the scientific method, the thought experiment is simply a play in logic -- and some simple mathematics -- that don't have the power to evolve. It remains logically speculative.

Quote:

---

Originally Posted by megafiddle

No, I wish I had one. But I will use the "bouncing photon clock" just to illustrate what I mean by "a thought experiment that is so simple".

The "experiment" is based on just three quantities, length, time, and velocity. Also it is based on just two scientific facts or principles, motion is relative,
and the velocity of light is constant for all observers.

It just seems that the following must be true:

The photon in the moving clock must travel a longer path between clock "ticks".
The photon must travel at the same velocity in the travelling clock as it does in the stationary (reference frame) clock.
Time = Distance / Velocity; therefore if distance increases, then time increases (time has slowed).

I would imagine though, that another thought experiment could just as well be a valid refutation, if one exists.

---

I say that the confusion is on the "experiment". We usually make an experiment because we want to observe something. If it is a thought experiment there is no observation, just imagination. So a thought experiment is more like a "thought exercise". Or it is jut a logical conclusion of a theorem as your example seems.

But without being too picky on the words, I would just say that a thought experiment is not a valid scientific experiment as anyway not all experiments are valid scientific experiments.

String Theory -> A reasonable argument with no experimental proofs; hence why it is not currently accepted as Scientific fact.