Title: Does consciousness really collapse the wave function?: A possible objective biophysical resolution of the measurement problem - ScienceDirect
Headings: Does consciousness really collapse the wave function?
: A possible objective biophysical resolution of the measurement problem

Biosystems
Does consciousness really collapse the wave function?: A possible objective biophysical resolution of the measurement problem
Abstract
Keywords
1. Introduction
2. The eye as a macroscopic apparatus and its possible role in resolving the measurement problem
3. Can Euglena collapse the wave function?
4. Proposed Ghirardi superposed photon-retinal tissue experiment
5. The “many worlds” interpretation of the measurement problem: can biophysics tell us something about quantum cosmology?
6. Discussion
7. Conclusion
Acknowledgements
References

Content: von Neumann (1932) advanced the theory that the possible states of a system can be characterized by state vectors, also known as wave functions, which change in two ways: continuously in a linear fashion as a result of a passage of time, as per Schrödinger's equation and, discontinuously if a measurement is carried out on the system ( Wigner, 1961, Shimony, 1963 ). This second type of discontinuous change, called the reduction of the state vector or collapse of the wave function, is unacceptable to many physicists. The measurement problem can then be posed as how and when does the wave function collapse or, how does a state reduction to one of the eigenstates of the measured observable occur. von Neumann (1932) was the first one to conceive this problem in terms of what is known as the ‘von Neumann chain’ ( Esfeld, 1999 ). He starts with a quantum object, an observable of which is to be measured. However, based on the formalism of quantum theory and the Schrödinger dynamics in particular, as a result of the interaction between the object and the measuring instrument, the object is entangled with the instrument. von Neumann extends this chain up to an observer but, if we take an observer into consideration, we simply end up with a description according to which the body of the observer, including his or her brain, is entangled with the instrument and the object. The measurement problem can then be further refined as to how it is that a state reduction to one of the eigenstates of the measured observable can occur in this chain ( Esfeld, 1999 ). von Neumann showed that as far as final results are concerned, you can cut the chain and insert a collapse anywhere you please ( Herbert, 1985 ).