Human beings crave relationship and interpersonal communication. To be human is to move from the desire to know things as objects to know people as subjects. Buber would never deny that human love and desire for knowledge is a very good thing, but he points out that this is not our primary goal and ultimate end. The ultimate end of the human being is, rather, to enter into relation with another Thou, set in relation to the I: “I do not experience the man to whom I say Thou. But I take my stand in relation to him, in the sanctity of the primary word” (15, emphasis added). This primary word is the word of I—Thou, and human experience of relation and interpersonal communion is wholly distinct from the experience of things in the world as objects.

In fact, it is only in relation that personal identity becomes real as well. The two realities of I and Thou are realities only when seen in relation to one another. In the same way that a father is only a father in light of the existence of a son or daughter, the I is only an I in light of the existence of another Thou (be it human or divine).