Many-minds interpretation

The many-minds interpretation is one of the interpretations of quantum physics, a modification to the many-worlds interpretation, itself derived from the Everett's relative-state formulation[?]. It was first published by D. Albert and B. Loewer in their 1988 work Interpreting the Many Worlds Interpretation.

The central problem of quantum theory is that it involves an unexplained duality in nature. For the majority of time systems will evolve according to the Schrödinger equation, evolving in a way that makes the system more and more indeterminant, becoming more "random" in the sense that it's physical qualities can take on a greater range of values. The second half of the duality occurs instantaneously during measurement of those physical qualities, at which time the system "selects" a single value of the range of possible values. This process is known as wavefunction collapse, and has no explaination. Worse, the process of observation occures "outside" the system, which is a huge problem on it's own if one considers the universe itself to be a quantum system. This is known as the measurement problem[?].

Everett attempted to find a way out of this problem by suggesting that the universe is in fact indeterminant as a whole, and that the measurment action changes the universe as a whole. That is, if you were to measure the spin of a particle and find it to be "up", in fact there are two "yous", one who measured the spin up, the other down. This "relative state" formulation, where all states (sets of measures) can only be measured relative to other such states, avoids a huge number of problems in quantum theory, including the original duality - no "collapse" takes place, the indeterminancy simply grows (or moves) to a larger system. Effectively by looking at the system in question, you take on its in indeterminancy.

Albert and Loewer associate with each observer a continuous infinity of minds. For any measure, the physical result is that many of these minds end up in one state or the other, for instance, spin up or spin down minds. "You" select one of these to be your non-random reality, while the universe itself is uneffected. On the downside, the process for selection of a single state remains unexplained. This is particularily problematic because it is not clear how different observers would thus end up agreeing on measurments, which happens all the time here in the "real world". There is assumed to be a sort of feedback between the mental process that leads to selection and the universal wavefunction, thereby effecting other mental states as a matter of course. In order to make the system work, the "mind" must be separate from the body, an old duality of philosophy to replace the new one of quantum mechanics.

In general the interpretation has received little attention, largely for this last reason.

External links:

On Many-Minds Interpretations of Quantum Theory (http://philsci-archive.pitt.edu/documents/disk0/00/00/02/09/index)