Scientific Determinism

[shekib82]

Is the universe fully determined, eg were a supreme being or a very powerful being to copy the universe in its early state create a parallel universe that would unfold in the exact same way as our universe, down to the everyday decisions made by every human being who lives or ever lived ?

In the 19th century the answer would have been yes, Pierre-Simon Laplace of the Laplace transform fame would say yes:

We may regard the present state of the universe as the effect of its past and the cause of its future. An intellect which at a certain moment would know all forces that set nature in motion, and all positions of all items of which nature is composed, if this intellect were also vast enough to submit these data to analysis, it would embrace in a single formula the movements of the greatest bodies of the universe and those of the tiniest atom; for such an intellect nothing would be uncertain and the future just like the past would be present before its eyes.
—Pierre Simon Laplace, A Philosophical Essay on Probabilities[34]

But in the 20th century the scientific discovery of Quantum Mechanism sheds strong doubts about the former statement. QM in its very nature is probabilistic. Particles can come into being at random, and the quantum process is part of our thought process. Of course, nothing is fully understood on this front. The probabilistic nature of QM might be an approximation and there might exist some hidden variables that would make QM deterministic, but this is not the opinion of most scientists today.

The current thinking is that a universe that started out just like ours would not unfold in the exact same way and there might be differences.

Does this means that the universe is not deterministic. Well, scientists today can be less confident of this than during Laplace's time.

 

[idb]

Is the universe fully determined, eg were a supreme being or a very powerful being to copy the universe in its early state create a parallel universe that would unfold in the exact same way as our universe, down to the everyday decisions made by every human being who lives or ever lived ?

In the 19th century the answer would have been yes, Pierre-Simon Laplace of the Laplace transform fame would say yes:

We may regard the present state of the universe as the effect of its past and the cause of its future. An intellect which at a certain moment would know all forces that set nature in motion, and all positions of all items of which nature is composed, if this intellect were also vast enough to submit these data to analysis, it would embrace in a single formula the movements of the greatest bodies of the universe and those of the tiniest atom; for such an intellect nothing would be uncertain and the future just like the past would be present before its eyes.
—Pierre Simon Laplace, A Philosophical Essay on Probabilities[34]

But in the 20th century the scientific discovery of Quantum Mechanism sheds strong doubts about the former statement. QM in its very nature is probabilistic. Particles can come into being at random, and the quantum process is part of our thought process. Of course, nothing is fully understood on this front. The probabilistic nature of QM might be an approximation and there might exist some hidden variables that would make QM deterministic, but this is not the opinion of most scientists today.

The current thinking is that a universe that started out just like ours would not unfold in the exact same way and there might be differences.

Does this means that the universe is not deterministic. Well, scientists today can be less confident of this than during Laplace's time.

Excellent question!!!!

 

[editec]

Yup.

Chaos means that advancing predictions in highly complex systems is impossible.

A lot of people don't really get that.

Since we live our lives in a SCALE where newtonian mechanistic physics seems to obvious and so prevelaant, its hard for some people not to think of the universe as have some kind of mechanistic determinability.

But there are at least two things in our lives that ought to tip us off about how chaos in the universe makes predicting the future state of highly complex systems impossible.

The WEATHER and (better still) the CLIMATE. Both (they're really just different periodical aspects of the same system) are impossible to predict long range because of the nature of those chaotic systems.

Another example of a chaotic complex system that is not truly predictable in the longer run is found in the world of MACROeconomics.

AGain the complexity of the macroeconomic sytem means that even very small changes in the system lead to massive changes to outcomes in the longer run.

And as there are billions of small changes happening constantly, prediction of what the macroeconomic system will look like in the distant future is quite impossible.

 

[Dr.Traveler]

I always considered Goddel's Incompleteness Theorem to be the nail in the coffin of a deterministic universe myself.