Quantum Measurement: The Observer Chooses Which Reality Gets Recorded

In the double-slit experiment, an electron or photon passes through two slits and leaves behind an interference pattern that behaves like a wave. The moment a detector records which slit the particle used, the interference pattern disappears. The result changes exactly when the path information comes into being, and related entanglement experiments were recognized in the 2022 Nobel Prize in Physics. This is a repeatable result in quantum physics, not a spiritual tale.

A measuring device needs no eyes and no consciousness. A detector, an environmental photon, or a stray atom hitting the particle can all mark the path. "Measurement" means the quantum system interacts with some object and leaves information that can be told apart. From the moment that information exists, the two ways through the slits stop combining the way they did before.