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Old May 1st 2008, 01:02 PM   #1
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Determinism of our Universe

Before having read about Laplace thoughts and the ones of the quantum mechanics, I already had an idea about the determinism of our Universe. I think it's almost natural to ask yourself about it. If we could have all the positions of all the particles, matter and so on, on a precise instant, could we know in advance how the Universe would evolve? I thought yes, as Laplace thought. But since the quantum physics appeared, we know that it is not possible. At a microscopic scale, our Universe is totally different in many ways of what it is at our scale. That is, if there exist a particle, it cannot have a position and a speed at the same time! And if a human try to determinate one of them, then the other would be unknown. But before taking those data, the particle doesn't have both qualities, which seems impossible to our scale. Therefore we cannot "put" the Universe data on an almost infinitely equation to determine how it can evolve. The quantum world is lead by probabilities, so we can only have probability of how would a simple system evolve. Thus, what was before a very important question about our Universe is now solved thanks to physics : the Universe is not "Laplacely determinist". Of course there is much more to know about this fascinating topic. I didn't read it, but I think this page is interesting. http://en.wikipedia.org/wiki/Determinism
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Old May 6th 2008, 07:48 AM   #2
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Determinism is usually considered in terms of a temporal cause and effect sequence.
However (with some brain stretching) one might consider a deterministic universe as a single multi-dimensional FIXED structure.

This evokes the meta-physical issues about self-awareness and (the illusion of) free-will in such an immutable system.

The probablistic descriptions of Shrodringer et al. seem to provide a much more fluid universe (which could arguably incorporate free-will).
However returning to the multi-dimensional universe, does this imply that the past is as fluid as the future?

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Old May 6th 2008, 01:22 PM   #3
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However returning to the multi-dimensional universe, does this imply that the past is as fluid as the future?
The answer is no. It is known that the past will never be again. Even if all the universe has a cycle life (which he doen't have), then the events would be repeated, not the time. The philosopher-physicist Étienne Klein (who is a specialist in question of Time) explains all about that in some of his books. I have here a nice video (but in French), about the Time question. http://www.cea.fr/var/cea/storage/st...TIPE/index.htm
Also what is surprising me at least is that if there were no matter, the Time would still exists.
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Old Jul 26th 2009, 08:10 PM   #4
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Also what is surprising me at least is that if there were no matter, the Time would still exists.
Time is imaginary. Just like numbers. Our consciousness creates the concept of time.

If intelligent life did not exist, neither would time.
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Old Jul 26th 2009, 10:08 PM   #5
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Originally Posted by Deco View Post
Time is imaginary. Just like numbers. Our consciousness creates the concept of time.

If intelligent life did not exist, neither would time.
Ok so according to you the concept of time started with intelligent life and will end with it, as well as the existence of time. I do not agree with this because of the following point : when one thinks about a mountain, does it make the mountain exist? Not to me.
So basically, saying that time is imaginary, to me, is the same as saying that time does not exist at all. And I've no idea about the veracity of this affirmation! It seems an open question.

About the sentence you quoted me, I just said what Klein said. Though now I realize it's its own point of view.
Since my last post in this thread I've found a paper where a very famous physicist (C.Rovelli) states that time is not necessary in physics and he gave a Hamiltonian (or 2? I don't remember) that does not involve time. I'm not familiar with this at all. So he seems to agree with the affirmation "time does not exist".
I'm just a second's year physics student and I'm very confused about what time is, if it is something. So don't be too hard on me .
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Old Jul 27th 2009, 04:12 AM   #6
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I agree with deco here.

The most satisfying definition (at least to me) of time that i ve heard to date is that " Time is the awareness/consciousness of the interval between two events" . If there is no awareness of change there is no time. Think of the unit of time "second". We say the "first" "second" and not the "first" "first" ! Maybe because without a second event time cant be registered.
This is an age old debate as to whether consciousness evolved from matter or vice versa.

I subscribe to the latter.

Another "definiton" which i like is that of consciousness.
" That which knows itself and the other". It is something like light. To see an object, we need light. But to see light itself, we dont need another light! Light is self luminous as it were. The same is true of consciuosness. What would be the colour of an object where there is no light? This question doesnt have much meaning as the concept of colour only comes after light. Similarly one point of view is that existence of any thing has a meaning only if consciousness is present, at least a background consciousness to certify it.

You know you exist. Does the best supercomputer know it does? You know it does. Does inert matter know it exists? But a conscious being knows it does.

Inert matter needs consiousness to certify its existence, consciousness doesn't need matter to certify its.

Just another point of view

Last edited by physicsquest; Jul 27th 2009 at 04:27 AM.
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Old Jul 27th 2009, 10:19 AM   #7
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Originally Posted by physicsquest View Post

Inert matter needs consiousness to certify its existence, consciousness doesn't need matter to certify its.

Just another point of view
I think we're going out of the subject of the thread but well... I don't really know what you mean by "certify" in the quoted sentence.
I personally see no difference between matter that acquired consciousness and matter that didn't, such as rocks. I know I need a brain to realize both exists, but I believe that without my brain, the rock would still exist.
Otherwise I don't see how life appeared if nothing existed before intelligent life. In my opinion life started with some matter that existed billions year before. Hence the no need to intelligent life to realize matter's existence. Of course it's my opinion and I'm not saying I'm telling the truth!

And about
The most satisfying definition (at least to me) of time that i ve heard to date is that " Time is the awareness/consciousness of the interval between two events"
the problem with time's definitions is that they ALL refer to time itself. It's well known that time is a primary word. For instance, the definition contains "interval between two events". You have to define that without time in order to say you have a good definition of time. According to Klein, there's no definition of time. (He's a physicist but also doctored in philosophy and earned great mentions for his thesis related to time).

As I implied before, I do not know if time is a property of the Universe or is just an illusion we have. I think the question is open and not solved, yet at least.
If we could describe all our current physics without time involved in equations and if we could go even further, then we would realize that time is an illusion, I believe. Not before.
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