ESTRAGON
His name is Godot?
VLADIMIR
I think so. (1.277-8)
The doubt surrounding Godot increases as the play continues. Now they cannot even be sure of the man’s name, arguably the one "fact" they were operating with until now.
ESTRAGON
Why doesn't he put down his bags?
[…]
ESTRAGON
Why doesn't he put down his bags? (1.407-15)
The asking of questions—often the same question over and over—sets the tone of uncertainty in Waiting for Godot.
ESTRAGON
They're coming!
VLADIMIR
Who?
ESTRAGON
I don't know.
VLADIMIR
How many?
ESTRAGON
I don't know.
VLADIMIR
(triumphantly) It's Godot! At last! Gogo! It's Godot! We're saved! Let's go and meet him! (2.378-83)
Vladimir takes Estragon’s uncertainty and draws a conclusion of assurance; in some ways, he’s regressed since Act 1, since he now can’t even admit that he is unsure of anything.