Although very existentialist in its characterizations, Waiting for Godot is primarily about hope. The play revolves around Vladimir and Estragon and their pitiful wait for hope to arrive. At various times during the play, hope is constructed as a form of salvation, in the personages of Pozzo and Lucky, or even as death. The subject of the play quickly becomes an example of how to pass the time in a situation which offers no hope. Thus the theme of the play is set by the beginning:
Estragon: Nothing to be done.
Vladimir: I'm beginning to come round to that opinion.
Although the phrase is used in connection to Estragon's boots here, it is also later used by Vladimir with respect to his hat. Essentially it describes the hopelessness of their lives.
A direct result of this hopelessness is the daily struggle to pass the time. Thus, most of the play is dedicated to devising games which will help them pass the time. This mutual desire also addresses the question of why they stay together. Both Vladimir and Estragon admit to being happier when apart. One of the main reasons that they continue their relationship is that they need one another to pass the time. After Pozzo and Lucky leave for the first time they comment:
V: That passed the time.
E: It would have passed in any case.
And later when Estragon finds his boots again:
V: What about trying them.
E: I've tried everything.
V: No, I mean the boots.
E: Would that be a good thing?
V: It'd pass the time. I assure you, it'd be an occupation.
Since passing the time is their mutual occupation, Estragon struggles to find games to help them accomplish their goal. Thus they engage in insulting one another and in asking each other questions.
The difficulty for Beckett of keeping a dialogue running for so long is overcome by making his characters forget everything. Estragon cannot remember anything past what was said immediately prior to his lines. Vladimir, although possessing a better memory, distrusts what he remembers. And since Vladimir cannot rely on Estragon to remind him of things, he too exists in a state of forgetfulness.
Another second reason for why they are together arises from the existentialism of their forgetfulness. Since Estragon cannot remember anything, he needs Vladimir to tell him his history. It is as if Vladimir is establishing Estragon's identity by remembering for him. Estragon also serves as a reminder for Vladimir of all the things they have done together. Thus both men serve to remind the other man of his very existence. This is necessary since no one else in the play ever remembers them:
Vladimir: We met yesterday. (Silence) Do you not remember?
Pozzo: I don't remember having met anyone yesterday. But to-morrow I won't remember having met anyone to-day. So don't count on me to enlighten you.
Later on the same thing happens with the boy who claims to have never seen them before. This lack of reassurance about their very existence makes it all the more necessary that they remember each other.
Estragon and Vladimir are not only talking to pass the time, but also to avoid the voices that arise out of the silence. Beckett's heroes in other works are also constantly assailed by voices which arise out of the silence, so this is a continuation of a theme the author uses frequently:
E: In the meantime let's try and converse calmly, since we're incapable of keeping silent.
V: You're right, we're inexhaustible.
E: It's so we won't think.
V: We have that excuse.
E: It's so we won't hear.
V: We have our reasons.
E: All the dead voices.
V: They make a noise like wings.
E: Like leaves.
V: Like sand.
E: Like leaves.
V: They all speak at once.
E: Each one to itself.
V: Rather they whisper.
E: They rustle.
V: They murmur.
E: The rustle.
V: What do they say?
E: They talk about their lives.
V: To have lived is not enough for them.
E: They have to talk about it.
V: To be dead is not enough for them.
E: It is not sufficient.
V: They make a noise like feathers.
E: Like leaves.
V: Like ashes.
E: Like leaves.
V: Say something!
One of the questions which must be answered is why the bums are suffering in the first place. This can only be answered through the concept of original sin. To be born is to be a sinner, and thus man is condemned to suffer. The only way to escape the suffering is to repent or to die. Thus Vladimir recalls the thieves crucified with Christ in the first act:
V: One of the thieves was saved. It's a reasonable percentage. (Pause.) Gogo.
V: Suppose we repented.
E: Repented what?
V: Oh . . . (He reflects.) We wouldn't have to go into the details.
E: Our being born?
Failing to repent, they sit and wait for Godot to come and save them. In the meantime they contemplate suicide as another way of escaping their hopelessness. Estragon wants them to hang themselves from the tree, but both he and Vladimir find it would be too risky. This apathy, which is a result of their age, leads them to remember a time when Estragon almost succeeded in killing himself:
E: Do you remember the day I threw myself into the Rhone?
V: We were grape harvesting.
E: You fished me out.
V: That's all dead and buried.
E: My clothes dried in the sun.
V: There's no good harking back on that. Come on.
Beckett is believed to have said that the name Godot comes from the French "godillot" meaning a military boot. Beckett fought in the war and so spending long periods of time waiting for messages to arrive would have been commonplace for him. The more common interpretation that it might mean "God" is almost certainly wrong. Beckett apparently stated that if he had meant "God," he would have written "God".
The concept of the passage of time leads to a general irony. Each minute spent waiting brings death one step closer to the characters and makes the arrival of Godot less likely. The passage of time is evidenced by the tree which has grown leaves, possibly indicating a change of seasons. Pozzo and Lucky are also transformed by time since Pozzo goes blind and Lucky mute.
There are numerous interpretation of Waiting for Godot and a few are described here:
Religious interpretations posit Vladimir and Estragon as humanity waiting for the elusive return of a savior. An extension of this makes Pozzo into the Pope and Lucky into the faithful. The faithful are then viewed as a cipher of God cut short by human intolerance. The twisted tree can alternatively represent either the tree of death, the tree of life, the tree of Judas or the tree of knowledge.
Political interpretations also abound. Some reviewers hold that the relationship between Pozzo and Lucky is that of a capitalist to his labor. This Marxist interpretation is understandable given that in the second act Pozzo is blind to what is happening around him and Lucky is mute to protest his treatment. The play has also been understood as an allegory for Franco-German relations.
An interesting interpretation argues that Lucky receives his name because he is lucky in the context of the play. Since most of the play is spent trying to find things to do to pass the time, Lucky is lucky because his actions are determined absolutely by Pozzo. Pozzo on the other hand is unlucky because he not only needs to pass his own time but must find things for Lucky to do.