Chapter 5, “Night Walkers and Mystery Mongers: Sense and Nonsense at the End of Science” (pp. 58-59)

Both Barnum and H. L. Mencken are said to have made the depressing observation that no one ever lost money by underestimating the intelligence of the American public. The remark has worldwide application. But the lack is not in intelligence, which is in plentiful supply; rather, the scarce commodity is systematic training in critical thinking.

— Carl Sagan

What It Means

This is a placeholder explanation generated by the low-overhead model. It interprets "Both Barnum and H. L. Mencken are said to have made the depressing observation that no one ever lost money by underestimating the intelligence of the American public. The remark has worldwide application. But the lack is not in intelligence, which is in plentiful supply; rather, the scarce commodity is systematic training in critical thinking." in the context of "Chapter 5, “Night Walkers and Mystery Mongers: Sense and Nonsense at the End of Science” (pp. 58-59)" to mean that wisdom is timeless.

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Source: Wikiquote: "Carl Sagan" (Quotes, Broca's Brain (1979): All page numbers are from the October 1980 mass market paperback edition published by Ballantine Books (28th printing) ) The 'What it means' explanation text was generated by Google Gemini Flash (accessed January 18, 2026). https://gemini.google.com/app
Carl Sagan

About Carl Sagan

Carl Edward Sagan (9 November 1934 – 20 December 1996) was an American astronomer, planetary scientist, cosmologist, astrophysicist, astrobiologist, author, and science communicator. His best known scientific contribution is research on extraterrestrial life, including experimental demonstration of the production of amino acids from basic chemicals by radiation. Sagan assembled the first physical messages sent into space, the Pioneer plaque and the Voyager Golden Record, universal messages that could potentially be understood by any extraterrestrial intelligence that might find them. Sagan argued the hypothesis, accepted since, that the high surface temperatures of Venus can be attributed to, and calculated using, the greenhouse effect. He testified to the US Congress in 1985 that the greenhouse effect will change the earth's climate system.