In quantum physics, which interpretation treats the wavefunction as a tool for predicting measurement outcomes?

In quantum physics, the Copenhagen interpretation treats the wavefunction as a tool for predicting measurement outcomes.

Developed mainly in the 1920s by Niels Bohr and Werner Heisenberg, it became the traditional interpretation of quantum mechanics. It emphasizes that quantum theory predicts probabilities for observations rather than definite properties existing independently of measurement. The wavefunction evolves smoothly according to the Schrödinger equation until a measurement is made, after which a particular result is obtained.

A central idea is complementarity: some experimental arrangements reveal wave-like behavior, while others reveal particle-like behavior, and these descriptions cannot be observed simultaneously in the same setup. The interpretation also stresses that the measuring apparatus must be described using ordinary, classical concepts.

“Copenhagen interpretation” is not a single perfectly formal doctrine; Bohr and Heisenberg expressed related but not identical views. It is also often confused with the claim that consciousness causes collapse, but that is not required by the interpretation. Alternatives include many-worlds, pilot-wave, and objective-collapse theories.