The play Waiting for Godotby Samuel Beckett treats the topic of loneliness from the perspective of social, mental, and spiritual isolation instead of treating it as a state of physical separation. The rationale behind the choice of treating this topic coincides with the play's existentialist influence, which contends that life is, itself, an isolated event with no real meaning nor purpose. This is why Waiting for Godot presents an atmosphere of melancholy, longing, and nonsense in the form of the actual wait for Godot: A person, entity, or thing that never manifests itself.
As a way to mock social injustice and the separation of the classes, we see how the character of Lucky seems to be left to his own devices. He is Pozzo's slave and property, which means that he must do as Pozzo pleases or else he will be punished. In his own world of a slave, Lucky is completely alone. Nobody would ever be able to help him change nor improve his situation.
In contrast, Pozzo seems to be completely codependent on Lucky. He is so used to live in his own superior world that he forgets that it is Lucky, and not himself who can help Pozzo survive. When Pozzo goes blind, he seems to need Lucky the most. This is how completely isolated from reality he is.
The mental loneliness comes in the form of Eragon: His limited mentality makes him forget and live in oblivion. He seems to miss out a lot of the action in the play as a result of his constant forgetfulness. He basically lives in a fog, and is led blindly through it by Vladimir, who is his protector.
Yet, Vladimir is nowhere content. He is waiting for Godot. He devotedly hopes for Godot to come in and....do what? We are not sure, as an audience, what difference Godot would make in his life. However, it is clear that the presence of Godot is quite a need in Vladimir's life. However, Godot never shows up.
The physical separation that we can appreciate comes from the unique status of the four main characters who, as a result of their random existence, happened to come together and end up in the same place. They are together, but each lives within their own little world. They all wait for Godot, but each of them does it in their own unique way. In the end, they all find at least one reason to declare that it is worthless to live. In Eragon's and Vladimir's case the situation is so bad that they do not even find the courage to do it.
In all, loneliness is treated in several different ways in the play Waiting for Godot. Each way pertains to the reality and limitations of each character. One thing is clear: They are all meant to be lonely wandering souls. That is one of the most central subtopics of the existentialist philosophy.