Many-minds Interpretation - Objections

Objections

Objections that apply to the many-worlds interpretation also apply to the many-minds interpretation. On the surface both of these theories expressly violate Occam's Razor; proponents counter that in fact these solutions minimize entities by simplifying the rules that would be required to describe the universe.

Another serious objection is that workers in no collapse interpretations have produced no more than elementary models based on the definite existence of specific measuring devices. They have assumed, for example, that the Hilbert space of the universe splits naturally into a tensor product structure compatible with the measurement under consideration. They have also assumed, even when describing the behavior of macroscopic objects, that it is appropriate to employ models in which only a few dimensions of Hilbert space are used to describe all the relevant behavior.

In his What is it like to be Schrödinger's cat? (2000), David Lewis argues that the many-minds interpretation of quantum mechanics has absurd implications for agents facing life-or-death decisions.

In general, the many-minds theory holds that a conscious being who observes the outcome of a random zero-sum experiment will evolve into two successors in different observer states, each of whom observes one of the possible outcomes. Moreover, the theory advises you to favor choices in such situations in proportion to the probability that they will bring good results to your various successors. But in a life-or-death case like getting into the box with Schrödinger's cat, you will only have one successor, since one of the outcomes will ensure your death. So it seems that the many-minds interpretation advises you to get in the box with the cat, since it is certain that your only successor will emerge unharmed. See also quantum suicide and immortality.

Finally, it supposes that there is some physical distinction between a conscious observer and a non-conscious measuring device, so it seems to require eliminating the strong Church–Turing hypothesis or postulating a physical model for consciousness.