In these aphorisms, Buber next launches into a meditation on the two different "I"s—the I of I–You and the I of I–It. The I of I–It he calls "ego". This I sees itself as a subject, fundamentally separate from other egos. The I of I–You he calls "person". Person sees itself as subjectivity, and conceives of itself in relation to other persons. Consciousness of person is a consciousness of the whole self, while consciousness of ego focuses only on what the self is like; the ego is obsessed with the idea of "my": my race, my nationality, my talent. Person, Buber tells us, participates in actuality, while ego does not.
There are no pure egos or pure persons, Buber explains, but people tend to be more inclined toward one or the other. He points us to three examples of very strong persons: Socrates was a strong person with an incredible capacity to say "You" to men, to converse with them; Goethe had a similar capacity to say "You" to nature; and Jesus could say "You" to God, the eternal You. Buber next gives us an example of a nearly pure ego, Napoleon Bonaparte. Napoleon, he claims, was so preoccupied with his a cause that even his self became an It. Though he was a You to many people (since he was seen as a great savior) he was utterly incapable of saying You to anyone.
Buber ends part two with a frighteningly vivid picture of a man in the grips of alienation. This imagined existential crisis occurs in the dead of night, during an insomniac episode. With his protective guard down, the man in our scenario is able to admit to himself, with horror, that his I is empty, and that he has completely ceased to live. He has the sense that he can still get to life, but he has no idea how to do so. He calls on thought to help him, because he is conditioned to rely on experience. Thought paints two pictures for him. In the first, man is represented as simply a part of the fabric of the world, so that there is no I at all. The world cannot be a threat to him since he is simply an indistinct part of it, so this picture calms him. Thought also presents another calming picture to the perturbed man. In this picture everything is a part of the I, everything is feeling and sensation. Again, there is no world distinct from the I on this picture, so the world cannot harm him. This picture soothes the man as well. Eventually, however, Buber tells us, the man will see both of these pictures at once and will become even more horrified than before.
Buber claims that man participates in actuality only insofar as he is person, and not insofar as he is ego. This is a puzzling because it seems that an ego is every bit as real or actual as a person. When Buber attempts to explain this claim, it becomes more confusing: only a person is actual because to be actual means to "participate in a being that is neither merely a part of him nor merely outside him". But this sounds like the very definition of what it is to be in a relation. So it sounds as if he is saying that the person is actual because person is the I of relation. Why should this be? The likeliest explanation is that Buber thinks that to be actual means to be an active participant in the world. A person needs to be engaged with the world, rather than an objective observer of it, on order to be actualized within the world. In the absence of relation, man is not any less real, he simply is not actualized within the world, because he has remained outside the world as an observer.
Perhaps even more puzzling than the discussion of actuality, is the two pictures of the universe that Buber presents at the very end of part two. What are these supposed to represent? In order to understand the significance of these two pictures it is necessary to look at the history of philosophy immediately preceding Buber's time. In response to the horror of realizing that a human being is a powerless individual and is at the mercy of the world, there are two standard responses. The first is to claim that man is not really anything separate from the world, because everything, including man, is actually just a part of God. Since man is not separate from the world, he has nothing to fear from it. This pantheistic response, most closely associated with the 17th century philosopher Baruch Spinoza and therefore often called "Spinozism", became wildly popular during the late 18th and early 19th centuries (long after Spinoza's death). German Romantics, such as Schopenhauer and Goethe, adopted this pantheistic worldview as their own, and took as their slogan the phrase "One and all". (Spinozism was actually a hallmark of the Romantics and one of the main points of contention between this group and the earlier generation of Enlightenment thinkers who found Spinoza's world view absurd.)
The other response to the horrific realization of man's vulnerability also seeks to make man identical with nature by claiming that the entire world is somehow dependent on, and nothing separate from, human thought. The world, in some subtle and complex sense, is entirely in the human head. Again, then, nature cannot harm man because it is not separate from man. Philosophers who might subscribe to this worldview include Kant, Fichte, and perhaps Schopenhauer.
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.