“We can be absolutely certain only about things we do not understand.”

“We may not understand why certain things occur in our lives, but we understand who to run to when they do.”

“the worst thing we can do, the absolute worst, is to do nothing.”

“The biggest mistake we can make is to think that we've figured the whole thing out. The people I know who are the greatest skeptics, who are least certain about how the world and the universe works, are also the most intelligent.... Absolute certainty is only for stupid people. It requires a certain intelligence for us to realize how little we actually know.”

“What can you do with a person who says that he is absolutely uncertain about everything, and that he is absolutely certain about that?”

“We cannot change our past. We can not change the fact that people act in a certain way. We can not change the inevitable. The only thing we can do is play on the one string we have, and that is our attitude.”