Friday, September 12, 2014

World is not deterministic

Quantum gravity physicist Marko Vojinovic posted on a philosophy site:
Despite all developments of modern science in the last century, a surprising number of laypeople (i.e., those who are not familiar with the inner workings of quantum mechanics) still appear to favor determinism over indeterminism. ...

By “determinism” I will refer to the statement which can be loosely formulated as follows: given the state of the Universe at some moment, one can calculate a unique state of the Universe at any other moment (both into the future and into the past). This goes along the lines of Laplace’s demon [2] and physical determinism [3], with some caveats about terminology ...

The analysis presented in the article suggests that we have only two choices: (1) accept that Nature is not deterministic, or (2) accept superdeterminism and renounce all knowledge of physics. To each his own, but apparently I happen to be predetermined to choose nondeterminism.

It is a fantastic achievement of human knowledge when it becomes apparent that a set of experiments can conclusively resolve an ontological question. And moreover that the resolution turns out to be in sharp contrast to the intuition of most people.
I mostly agree with this. If determinism means completely defined by observables or hidden variables obeying local differential equations, then quantum mechanics and chaos theory show it to be impossible.

In the comments, some argue that some interpretations of quantum mechanics (many worlds and Bohmian) are formally deterministic. But this is mainly playing stupid word games. What good is determinism, if the outcome is only determined on some goofy parallel universe that no one can ever interact with?

Einstein had a religious belief in determinism, and so he rejected quantum mechanics. History has favored quantum mechanics.


  1. This comment has been removed by the author.

  2. "History has favored quantum mechanics. "

    So why does marko waste his life on quantum gravity?

  3. Einstein didn't reject quantum mechanics. He hoped for a deterministic model of quantum mechanics.

    1. That is like saying: Republicans do not reject Obama. They just hope for a president with Republican policies.

      Yes, read the Bohr–Einstein debates.