Realism Without Interphenomena: Reichenbach's Cube, Sober's Evidential Realism, and Quantum Solipsism

ABSTRACT In ‘Reichenbach's cubical universe and the problem of the external world’, Elliott Sober attempts a refutation of solipsism à la Reichenbach. I here contrast Sober's line of argument with observations a hypothetical scientist makes on what is known as the ‘Mermin contraption’ and show that Sober's extension of Reichenbach's argument fails. However, there is a further line of defense against solipsism, endorsed by some interpreters of the quantum theory whose position is otherwise rather close to solipsism. As I shall argue, this line of defense remains viable, but we still fall short of a story in terms of what Reichenbach calls ‘interphenomena’ in the case of the Mermin contraption.