This paper provides an analysis of Franz Brentano’s thesis that psychology employs a distinctive method, which sets it apart from physiology. The aim of the paper is two-fold: First, I situate Brentano’s thesis (and the broader metaphysical system that underwrites it) within the context of specific debates about the nature and status of psychology, arguing that we regard him as engaging in a form of boundary work. Second, I explore the relevance of Brentano’s considerations to more recent debates about autonomy on the one hand and theoretical and/or methodological integration on the other. I argue that Brentano puts his finger on the idea that an integrated research process presupposes the existence of distinct methods and approaches, and that he highlights the philosophical challenge of accounting for such distinct methods. I suggest that Brentano’s ideas offer unconventional perspectives on current debates, in particular regarding first-person methods and the investigative process in cognitive science