“When your reasons for believing something are justified ad hoc, you are left susceptible to further discoveries undermining the rationale for that belief.”

“Where ignorance lurks, so too do the frontiers of discovery and imagination”

“Robots are important also. If I don my pure-scientist hat, I would say just send robots; I'll stay down here and get the data. But nobody's ever given a parade for a robot. Nobody's ever named a high school after a robot. So when I don my public-educator hat, I have to recognize the elements of exploration that excite people. It's not only the discoveries and the beautiful photos that come down from the heavens; it's the vicarious participation in discovery itself.”

“... there is no shame in not knowing. The problem arises when irrational thought and attendant behavior fill the vacuum left by ignorance.”

“Still, our knowledge of the planets was meager, and where ignorance lurks, so too do the frontiers of discovery and imagination.”

“Some morning while your eating breakfast and you need something new to think about, though, you might want to ponder the fact that you see your kids across the table not as they are but as they once were, about three nanoseconds ago.”

“When scientifically investigating the natural world, the only thing worse than a blind believer is a seeing denier.”