Quote 4
POZZO
(calmer) Gentlemen, I don't know what came over me. Forgive me. Forget all I said. (More and more his old self.) I don't remember exactly what it was, but you may be sure there wasn't a word of truth in it. (1.485)
Pozzo is at least certain of his uncertainty, which is more than we can say for Vladimir—at least in Act 1.
POZZO
It isn't by any chance the place known as the Board?
VLADIMIR
Never heard of it.
POZZO
What is it like?
VLADIMIR
(looking round) It's indescribable. It's like nothing. There's nothing. There's a tree.
POZZO
Then it's not the Board. (2.707-11)
Pozzo convinces himself of "facts" by using an arbitrary and contrived system of logic. The fact that there is a tree in the scenery has absolutely nothing to do with whether or not this is "the Board." (Actually, "the Board" is an old word for "stage," so in fact the setting IS the Board. Pozzo is not only faking certainty, he’s just plain wrong.)
Quote 6
POZZO
(having lit his pipe) The second is never so sweet . . . (he takes the pipe out of his mouth, contemplates it) . . . as the first I mean. (He puts the pipe back in his mouth.) But it's sweet just the same. (1.400)
This is Pozzo putting in his two cents to add to Gogo and Didi’s earlier conversation about the carrot. His opinion is something of a middle ground; habit deadens the senses, but there is still something to be enjoyed in the world.