Franz Brentano, in attempting to distinguish between mental and physical phenomena, uses “presentation” to be the single defining characteristic of mental phenomena. Specifically, Brentano identifies the “acts of presentation” as necessarily mental phenomena, and in so doing identifies a structure in which the mental activity is always “intentional” insofar as it refers toward some object. Thus, for a given state to be considered mental, it must necessarily be considered an act of presentation and as directed towards some content. A large number of conscious states which appear to be obviously mental share this feature. Certain emotional states, however, seem to lack the same intentional structure, and reveal themselves as fault lines in this touchstone of mental phenomena. Beyond sealing these vulnerable surface fractures, it is also important to consider whether the overall method of developing the distinction between mental and physical phenomenon is apposite at all.
"The Ineluctable Intentionality of Mental Phenomena,"
Colgate Academic Review: Vol. 4
, Article 4.
Available at: http://commons.colgate.edu/car/vol4/iss1/4