The trouble was that he was talking in philosophy but they were listening in gibberish.

I’m not superstitious. I’m a witch. Witches aren’t superstitious. We are what people are superstitious of.

The trouble is you can shut your eyes but you can’t shut your mind.

We are here and it is now. The way I see it is, after that, everything tends towards guesswork.

What's a philosopher?' said Brutha.
Someone who's bright enough to find a job with no heavy lifting,' said a voice in his head.

Don't you understand?" snarled Rincewind. "We are going over the Edge, godsdammit!"
"Can't we do anything about it?"
"No!"
"Then I can't see the sense in panicking," said Twoflower calmly.