Some people think Wheeler's gotten crazy in his later years, but he's always been crazy.

We absolutely must leave room for doubt or there is no progress and no learning. There is no learning without having to pose a question. And a question requires doubt. People search for certainty. But there is no certainty.

Have no respect whatsoever for authority; forget who said it and instead look what he starts with, where he ends up, and ask yourself, "Is it reasonable?"

Observation, reason, and experiment make up what we call the scientific method.

Start out understanding religion by saying everything is possibly wrong... As soon as you do that, you start sliding down an edge which is hard to recover from.

We never are definitely right, we can only be sure we are wrong.

Scientific knowledge is an enabling power to do either good or bad — but it does not carry instructions on how to use it.