The three major metaphysical aspects of quantum mechanics are:

1. Particle-wave duality.
2. The role of the act of observation in creating reality.
3. Nonlocality (spooky action at a distance).

Particle-wave duality and nonlocality, as metaphysical as they may seem, are aspects that have been observed experimentally and so would seem to be definitely a part of our physical reality.

But what about the quantum mechanical formalism that the act of observation actually creates reality? The central problem, of course, is who is the observer?

What do you think?