In one day, both of their lives undergo a radical change. Pozzo’s dialogue in Act 2 is an excellent manifestation of this idea of the uncertainty of life which is ironically part of the limited certainties in the universe:
“Have you not done tormenting me with your accurse time…One day, is that not enough for you, one day he went dumb one day, I went blind, one day we’ll go deaf, one day we were bone, one day we shall die, the same day, the same second, is that not enough for you? They give birth astride of a grave, the light gleams an instant, then its night once more. (He jerks the rope) On!” (Waiting for Godot, p.