Quantum phenomena do not occur in a Hilbert space. They occur in a laboratory.
Asher Peres (1995). Quantum theory: concepts and methods. Springer. p. 373. ISBN 0792336321.
Some authors state that the last stage in this chain of measurements involves "consciousness," or the "intellectual inner life" of the observer, by virtue of the "principle of psycho-physical parallelism." Other authors introduce a wave function for the entire universe. In this book, I shall refrain from using concepts that I do not understand.
Asher Peres (1995). Quantum theory: concepts and methods. Springer. p. 26–27. ISBN 0792336321.
Unperformed experiments have no results.
Title of a 1978 paper, Peres, Asher (1978). "Unperformed experiments have no results". American Journal of Physics46: 745. DOI:10.1119/1.11393.