One of the great triumphs of modern science is the theory of quantum mechanics, one of the most successful ideas in history. Every experiment ever done is compatible with its predictions and despite numerous attempts, physicists have never been able to create conditions in which it doesn’t work.
But quantum theory’s success forces physicists to accept a number of uncomfortable truths. For example, it allows “spooky action at a distance” between entangled particles. This occurs when two particles become so deeply linked that a measurement on one instantly determines the state of the other, regardless of the distance between them.
Since then, physicists have studied spooky-action-at-a-distance in detail; it is straightforward to observe in a quantum optics laboratory. It is now even exploited in technologies such as quantum cryptography.
Another uncomfortable conclusion is that the quantum universe is governed by probabilistic behavior. At any instant, lots of different things could happen but the thing that actually happens is determined by probability, essentially on the roll of a dice.
This thinking forces physicists to the conclusion that our deterministic experience of the universe is an illusion. Indeed, there is little debate among physicists that the foundation of reality is fundamentally and weirdly probabilistic.
