Richard Biehl, Police Chief of Dayton, Ohio:

I want them to be worried that we're watching.

I want them to be worried that they never know when we're overhead.

Simon Critchley:

We always have to acknowledge that we might be mistaken.

When we forget that, then we forget ourselves and the worst can happen.

Louis Menand:

We fall in love with our hunches, and we really, really hate to be wrong.

We are not natural falsificationists: we would rather find more reasons for believing what we already believe than look for reasons that we might be wrong.

An exchange from "Doubt", with Philip Seymour Hoffman:

Father Brendan Flynn: You haven't the slightest proof of anything!

Sister Aloysius Beauvier: But I have my certainty!