Abstract

David Albert and Barry Loewer have proposed a new interpretation of quantum mechanics which they call the Many Minds interpretation, according to which there are infinitely many minds associated with a given (physical) state of a brain. This interpretation is related to the family of many worlds interpretations insofar as it assumes strictly unitary (Schrödinger) time-evolution of quantum-mechanical systems (no reduction of the wave-packet). The Many Minds interpretation itself is principally motivated by an argument which purports to show that the assumption of unitary evolution, along with some common sense assumptions about mental states (specifically, beliefs) leads to a certain nonphysicalism, in which there is a many-to-one correspondence between minds and brains. In this paper, I critically examine this motivating argument, and show that it depends on a mistaken assumption regarding the correspondence between projection operators and yes/no questions.