Von Neumann–Wigner interpretation

The von Neumann–Wigner interpretation, also described as "consciousness causes collapse [of the wave function]", is an interpretation of quantum mechanics in which consciousness is postulated to be necessary for the completion of the process of quantum measurement.

Quotes

 * Of course, quantum mechanics is tinged with this kind of solipsism, because there is a sense in which an electron doesn’t really have any properties until you measure it. There is a subjective aspect to quantum mechanics. Some experts like Eugene Wigner were convinced the universe wouldn’t exist if it didn’t have observers in it. He argued that, without a conscious mind observing the quantum events, the events don’t really exist, which I think is a crazy point of view. But it is defended by a number of quantum mechanics experts.
 * Martin Gardner, in "Interview with Martin Gardner", Notices of the AMS (June/July 2005)