Brentano and J. Stuart Mill on Phenomenalism and Mental Monism

This study is about Brentano’s criticism of a version of phenomenalism that he calls “mental monism” and which he attributes to positivist philosophers such as Ernst Mach and John Stuart Mill. I am interested in Brentano’s criticism of Mill’s version of mental monism based on the idea of “permanent possibilities of sensation.” Brentano claims that this form of monism is characterized by the identification of the class of physical phenomena with that of mental phenomena, and it commits itself to a form of idealism. Brentano argues instead for a form of indirect or hypothetical realism based on intentional correlations.