There has been a good deal of interest in recent years in what Franz Brentano had to say about the notion of ‘intentional objects’ and about intentionality as a criterion of the mental. There has been less interest in his classification of mental phenomena. In his Psychology from an Empirical Standpoint Brentano asserts and argues for the thesis that mental phenomena can be classified in terms of three kinds of mental act or activity, all of which are directed towards an immanent object. These are, respectively, presentation, judgment and what he calls the phenomena of love and hate. Once again, less interest has been shown in what he has to say about the last of these three than in what he says about the others. I wish to take Brentano's views as the point of departure for a discussion of love and hate, since these notions seem to me to have a good deal of philosophical interest, for at least two main reasons. First, I have recently had some concern with the part that personal relations play in our understanding of others and of ourselves, and love and hate seem to be very important elements in such relations. Second, love and hate have long seemed to me to provide important counter-examples to some prevalent philosophical theories about the emotions. I shall take this issue first.