Abstract
R. M. Chisholm interprets Brentano’s theory of intentionality through the lens of two theses: the ontological thesis, according to which the intentionality of the mental designates the fact that there is an immanent object in the act; and the psychological thesis, according to which intentionality consists of the direction of the mental act toward the extra-mental object. In my paper I interpret Chisholm’s and Brentano’s theses on intentionality from two perspectives: intentionality as the most salient distinguishing feature separating the mental from the physical (Chisholm’s ontological thesis), and intentionality as a theory of the way in which mental acts with their content are related to extra-mental but theoretically-constructed objects of physics (Chisholm’s psychological thesis). Thus, an important issue of my paper is also to show that Chisholm’s well-known ontological and psychological theses on Brentanian intentionality rest on presuppositions that do not fit the program of Brentanian psychology.