Quantum theory and Laplace’s demon

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asked 8 years ago

Hello Rabbi

There is a fatalistic saying known as “Laplace’s Demon” according to which an intellect which at a certain moment knew all the forces and laws operating in nature and all the locations of all the items of which the universe is composed, if this intellect were powerful enough to apply an appropriate analysis to this information, it would summarize in a single formula the movements of the largest bodies in the universe as well as that 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.
As a believing Jew, I think there are 2 factors that violate this calculus, and they are:
‘Divine Providence’ capable of intervening and miraculously changing the laws or states of nature
‘Human choice’, which, while not capable of changing the laws of nature, is capable of violating the deterministic natural state and can change the picture of the universe according to the limitations of human capabilities.
My question is, does quantum theory contradict the above?
Does superposition at the micro level mean that even without the 2 variables I mentioned (divine providence and human choice) it is not possible to predict the future state of the universe in light of its current state?

thanks

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מיכי Staff answered 8 years ago

Hello Tzvia. First, Laplace does not claim that there is one formula. That was Einstein’s hope to find a unified field theory. But it is not clear that there is one, and I do not think Laplace assumed that there was one. What he claimed was that everything that would happen could be described, but using several formulas rather than one. Second, quantum theory does indeed refute Laplace’s claim and the classical concept of causality in general. Unless a complete theory of hidden variables is found, which currently seems unlikely. Third, if you believe in free will and certainly in divine intervention, this does not align with Laplace’s words. He was a determinist. But these are beliefs and not findings, and therefore it is difficult to see them as a critique of his words. The question is open: can someone who is a determinist accept Laplace’s claim (except for the reservations about quantum theory), and who does not cannot help but accept it.

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צביה replied 8 years ago

My question was of course about the possibility of prediction without divine or human involvement.

Is the concept of causality also unfounded at the micro level? After all, we see that causality works well in all areas of life in what is visible to the eyes and senses.

Thank you

מיכי Staff replied 8 years ago

Baruch from the resurrection of the dead. It's a bit difficult to engage in such a discussion with two-month intervals between messages.
In the macro that is visible to the senses – yes, in the micro in quantum theory – no.

koby replied 3 years ago

This is the basis of our entire understanding of the concept of prayer - if a Jew can change or influence events in the world - through his prayer - if it is God's will... then nothing can be predicted - otherwise what is the value of prayer?