What Is Real?: The Unfinished Quest for the Meaning of Quantum Physics

by Adam Becker

Von Neumann’s solution was to make the observer—whoever was looking—responsible for wave function collapse. “We must always divide the world into two parts, the one being the observed system, the other the observer,” Von Neumann said. “Quantum mechanics describes the events which occur in the observed portion of the world, so long as they do not interact with the observing portion, with the aid of the [Schrödinger equation], but as soon as such an interaction occurs, i.e. a measurement, it requires the [collapse of the wave function].” It’s not entirely clear what von Neumann meant by this. Some took him to be saying that consciousness itself causes the collapse of the wave function; this was a view promoted by physicists Fritz London and Edmond Bauer in a book they wrote several years later, heavily influenced by von Neumann’s work. Wigner also adopted this view later. But this is a weird view. Stating that consciousness collapses wave functions does arguably solve the measurement problem but only at the price of introducing new problems. How could consciousness cause wave function collapse? Since wave function collapse violates the Schrödinger equation, does that mean that consciousness has the ability to temporarily suspend or alter the laws of nature? How could this be true? And what is consciousness anyhow? Who has it? Can a chimp collapse a wave function? How about a dog? A flea? “Solving” the measurement problem by opening the Pandora’s box of paradoxes associated w...