"To live is to be separated from what we were in order to approach what we are going to be in the mysterious future. Solitude is the profoundest fact of the human condition. Man is the only being who knows he is alone, and the only one who seeks out another."
Paz considers the human life as a preparatory phase. The familiar is constantly stripped away as soon as it becomes familiar because time never stops running along. The solitude which Paz feels most profoundly and identifies in the lives of people around him is a result of cognition. Since man knows he is alone, he searches outside of himself.
"Love is an attempt to penetrate another being, but it can only be realized if the surrender is mutual."
In the physical and emotional demonstration of love, people try to reach one another. They're making an effort to end this prison of solitude. In the act, however, the breakthrough only works if both parties are participating. Both must be striving with abandon to reach the other.
"It is always difficult to give oneself up; few persons anywhere ever succeed in doing so, and even fewer transcend the possessive stage to know love for what it actually is: a perpetual discovery, and immersion in the waters of reality, an unending re-creation."
When Paz writes "to give oneself up" he means to abandon the idea of the other for the perception of the other. In relationships, people are constantly tempted to view the other person as an object or, at the least, as a static being. This simply isn't compatible with true surrender because the dynamic nature of existence leads to a perpetual reformation of self. To know someone is to keep up with that person.
"His nature -- if that word can be used in reference to man, who has 'invented' himself by saying 'no' to nature -- consists in his longing to realized himself in another. Man is nostalgia and a search for communion. Therefore, when he is aware of himself he is aware of his lack of another, that is, of his solitude."
Paz believes the experience of human existence is primarily one of solitude. The process of knowing oneself involves an immediate recognition of separation, for what is "me" is not "you," and there exists a profound desire to rectify that separation. In Paz' consideration, he believes the identity is a construction, a deliberate refusal to conform to the base nature of existence in order to build something out of one's mind.