MENTAL AND PHYSICAL PHENOMENA

In this chapter, I will set out what I take to be the basic tenets of Franz Brentano's epistemology. This seemingly simple task is a crucial one because virtually every other aspect of Brentano's philosophy uses his epistemology as a starting point and is structured in the same way. As the title of his major published work, Psychology from an Empirical Standpoint, suggests, Brentano saw himself as an empiricist; his account of knowledge, belief and other epistemological concepts is therefore constructed from the building blocks, so to speak, of the phenomena of experience.

According to Brentano, these phenomena are of two kinds, mental and physical, and he believes all human experience is experience of one or other of these phenomena. So we first have to see how he differentiates between mental and physical phenomena, between the mental and the physical. He lays out this distinction in the first chapter of Book 2 of his Psychology, entitled “On the Distinction Between Mental and Physical Phenomena.” Brentano first surveys several ways of laying out the distinction between these two classes of experiential phenomena. He then enumerates examples of mental and physical phenomena, and then tries to find the defining characteristics of mental phenomena. He identifies several characteristics which he thinks all mental phenomena have and all physical phenomena lack. Far and away the most important of these in his estimation, and the one which has aroused the most interest on the part of later philosophers, is what he calls “intentional inexistence.”