“People are not stupid. They believe things for reasons. The last way for skeptics to get the attention of bright, curious, intelligent people is to belittle or condescend or to show arrogance toward their beliefs.”

Iraq? They just need to think it through (2007)
Context: There isn't just one point; it takes time to learn. You don't have to be intelligent, but I think you have to be open to possibilities and willing to explore. The only stupid people are those who are arrogant and closed off.

Wer es versteht, den Leuten mit Anmut und Behagen Dinge auseinander zu setzen, die sie ohnehin wissen, der verschafft sich am geschwindesten den Ruf eines gescheiten Menschen.
Source: Aphorisms (1880/1893), p. 37.

The New High Intensity Training (2004)

Source: The Diamond Age: or, A Young Lady's Illustrated Primer

The Plague (1947)

http://www.imdb.com/title/tt0894112/ (1996)

Part 2, Chapter 4, “The Mystery of the Champagne Supernovae” (p. 128).
Jack Glass (2012)