Page "Determinism" Paragraph 71

Some ( including Albert Einstein ) argue that our inability to predict any more than probabilities is simply due to ignorance.

The idea is that, beyond the conditions and laws we can observe or deduce, there are also hidden factors or " hidden variables " that determine absolutely in which order photons reach the detector screen.

They argue that the course of the universe is absolutely determined, but that humans are screened from knowledge of the determinative factors.

So, they say, it only appears that things proceed in a merely probabilistically determinative way.

In actuality, they proceed in an absolutely deterministic way.

These matters continue to be subject to some dispute.

A critical finding was that quantum mechanics can make statistical predictions which would be violated if local hidden variables really existed.

There have been a number of experiments to verify such predictions, and so far they do not appear to be violated.

This would suggest there are no hidden variables, although many physicists believe better experiments are needed to conclusively settle the issue ( see also Bell test experiments ).

Furthermore, it is possible to augment quantum mechanics with non-local hidden variables to achieve a deterministic theory that is in agreement with experiment.

An example is the Bohm interpretation of quantum mechanics.