Encounter between human beings, Buber tells us in the nineteenth aphorism, is best described as love. But only love as he understands it, not as most people do. This is because most people misunderstand love: They believe that love is a feeling, when really it is more like a cosmic force. Feelings are something that we have, something that inside he who is the feeling. Love, on the other hand, is something between two people, something that we dwell in rather than something that dwells in us. We do not have love, but live inside of it. And, of course, we are transformed by it. It is only love understood in this way that captures relation between two people.
When we love someone we see that person as wholly unique, and without any qualities. The person is purely present, and not separated from us by anything. Even in love, though, the You must inevitably fade periodically into an It. As soon as we see your beloved as beautiful, kind, brown-haired, blue-eyed, sweet- smelling, noisy, the beloved has ceased to be a You. This does not mean that love cannot endure, but only that it constantly oscillates between actuality and potentiality. (This fleeting nature of encounter between human beings is very important because it leads us to yearn for God, the eternal You.) So long as we have been in encounter with someone and know that we have the potential to do so again at any moment, we can say that we love that person. If, on the other hand, we have never encountered someone (or if we no longer have the potential to do so) then we do not really love that person.
To love someone, Buber tells us further, is to feel a responsibility for that person, to want to do everything one can to help that person. Unlike feelings, which can be greater or lesser, all love is equal, and all who love are equal as lovers: someone who loves just one human being and suffers nothing for his love is no lesser than someone who loves all human beings and suffers greatly for his love.
Before moving on from the topic of love, Buber considers a possible objection to his claim that relation between men can be described as love: what about hatred? Is hatred not also a relation that can obtain between men? The answer, he says adamantly, is "no". Relation, by its very definition, can only be directed toward a whole being. But hatred, by its very nature, cannot be directed toward a whole being. We cannot hate a whole person, only a part of a person. Hatred, he tells us, not love, is blind. Still, he admits, whoever hates directly is closer to being in relation than someone who neither loves nor hates at all.
Though the notion of encounter is vague and difficult to grasp fully, thinking about encounter as the more familiar experience of being in love can be extremely enlightening. Take, for instance, one of the unanswered questions from the last section: what does Buber mean when he says that during encounter we view the entire Universe through the You? Though it remains difficult to analyze this statement in any precise way, thinking about encounter as love certainly makes the idea easier to grasp. When we are in love our entire perception of the world becomes colored by the beloved, and we view everything in relation to the beloved: locations become good or bad depending on how close they are to the beloved; people become important or unimportant depending on their relation to the beloved; a song, a scent, or a word can become precious just because it serves as a reminder of the beloved. In this sense, the lover views the entire universe through the beloved.
Thinking about encounter as love also helps us understand why Buber believes that encounter is so terrifying. When you truly allow yourself to love someone you become incredibly vulnerable. First of all, you suffer the risk of rejection and loss. In addition, if you love in the way that Buber requires, so that the pain and happiness of the beloved are even more important to you than your own, then you are taking on an even graver risk. Suddenly, you are multiplying your potential for grief (though perhaps also your potential for joy).
The identification of love as relation between people also brings along some new worries. For instance, it raises the problem of unrequited love. Relation must be mutual, because it is reciprocal and involves mutual transformation. It seems strange to claim that you cannot love someone if they do not return your love, but this is what Buber will have to claim: you cannot dwell in the cosmic force unless the beloved dwells in the force with you. Buber does admit in the Afterword that no relation can be entirely mutual, and that some relations, such as that between student and teacher, between therapist and patient, and between spiritual leader and congregant, should not even strive for complete mutuality, but he seems to clearly believe that entirely unrequited love cannot be love at all.
Relations are not either / or, but varry in degree. The closer one comes to a genuine I-You relationship, the more likely one is drawn to service, and increasing I-You relationships.