All of physics is based on quantum theory. It’s the most battle-tested theory in all of science. And one-third of our economy involves products designed with it. Quantum theory works for fundamental science and for practical applications.
However, this reliable and useful physics challenges any reasonable worldview. It actually denies the existence of a physically real world independent of its observation. It also tells of a strange connectedness.
Demonstrating quantum strangeness is practical only for small objects, though as technology improves, it’s being displayed for larger and larger things. Quantum theory is presumed to be valid for everything. Quantum cosmologists apply it for the whole of the early universe.
Here are quantum theory’s reality and connectedness problems in a nutshell:
Reality: By your free choice you could demonstrate either of two contradictory physical realities. You can, for example, demonstrate an object to be someplace. But you could have chosen to demonstrate the opposite: that it was not in that place. Observation created the object’s position. Quantum theory has all properties created by their observation.
Connectedness: Quantum theory tells that any things that have ever interacted are forever connected, “entangled.” For example, your friend’s freely made decision of what to do in Moscow (or on Mars) can instantaneously (though randomly) influence what happens to you in Manhattan. And this happens without any physical force involved. Einstein called such influences “spooky actions.” They’ve now been demonstrated to exist. But for human-scale things, the effect is impossible to detect, for all practical purposes. It is “averaged out” by all the other things that are happening. But nevertheless…
Two more comments:
The quantum weirdness is not hard to “understand”–even with zero physics background. But it’s almost impossible to believe . When someone tells you something you can’t believe, you might well think you don’t understand. But believing might be the real problem. It’s best to approach the subject with an open mind. That’s not easy.
The experimental facts basic to the quantum enigma are undisputed. But talking of the encounter of physics with “non-physical” stuff like consciousness is controversial. It’s been called our “skeleton in the closet.” You can look at the undisputed facts, and ponder for yourself what they mean.
To see some things leading developers of quantum mechanics have said, click on a name.