Which interpretation of quantum mechanics denies hidden variables and emphasizes measurement?

The Copenhagen interpretation is the interpretation of quantum mechanics most associated with rejecting hidden variables as necessary and emphasizing the role of measurement. It developed through discussions involving Niels Bohr, Werner Heisenberg, and other physicists during the 1920s.

In this view, quantum mechanics predicts the probabilities of measurement outcomes rather than assigning every observable a definite value in advance. A system is represented by a wavefunction, and measurement produces a definite result. The interpretation also stresses complementarity: phenomena such as wave and particle behavior are different but necessary aspects of quantum descriptions.

“Copenhagen interpretation” is not a single perfectly codified doctrine. Bohr and Heisenberg held somewhat different philosophical positions, and later writers grouped several related ideas under the label. Still, it is the standard quiz answer when a question highlights measurement, probability, and the rejection of classical hidden properties.

It is commonly contrasted with Bohmian mechanics, which explicitly introduces hidden variables, and with many-worlds, which avoids wavefunction collapse by treating all outcomes as branches. The transactional interpretation uses another specialized account of quantum events.