   In the two paragraphs quoted above, Brentano sketches an entire research programme based on three distinct theses. According to the first thesis, it is constitutive of the phenomenon of intentionality, as it is exhibited by mental states such as loving, hating, desiring, believing, judging, perceiving, hoping and many others, that these mental states are directed towards things different from themselves. According to the second thesis, it is characteristic of the objects towards which the mind is directed by virtue of intentionality that they have the property which Brentano calls intentional inexistence. According to the third thesis, intentionality is the mark of the mental: all and only mental states exhibit intentionality.