There is no compelling evidence that UFOs are not visiting the Earth; therefore UFOs exist — and there is intelligent life elsewhere in the universe. Or: There may be seventy kazillion other worlds, but not one is known to have the moral advancement of the Earth, so we're still central to the Universe.) This impatience with ambiguity can be criticized in the phrase: absence of evidence is not evidence of absence." - Meaning and context.">
QuotesCosmos
Ch. 12 : The Fine Art of Baloney Detection, p. 221
• Referring to an aphorism of Martin Rees. (see Misattributed below)
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Appeal to ignorance — the claim that whatever has not been proved false must be true, and vice versa (e.g. There is no compelling evidence that UFOs are not visiting the Earth; therefore UFOs exist — and there is intelligent life elsewhere in the universe. Or: There may be seventy kazillion other worlds, but not one is known to have the moral advancement of the Earth, so we're still central to the Universe.) This impatience with ambiguity can be criticized in the phrase: absence of evidence is not evidence of absence.

— Carl Sagan

What It Means

This is a placeholder explanation generated by the low-overhead model. It interprets "Appeal to ignorance — the claim that whatever has not been proved false must be true, and vice versa (e.g. There is no compelling evidence that UFOs are not visiting the Earth; therefore UFOs exist — and there is intelligent life elsewhere in the universe. Or: There may be seventy kazillion other worlds, but not one is known to have the moral advancement of the Earth, so we're still central to the Universe.) This impatience with ambiguity can be criticized in the phrase: absence of evidence is not evidence of absence." in the context of "Ch. 12 : The Fine Art of Baloney Detection, p. 221
• Referring to an aphorism of Martin Rees. (see Misattributed below)" to mean that wisdom is timeless.

Quote Image
Source: Wikiquote: "Carl Sagan" (Quotes, The Demon-Haunted World : Science as a Candle in the Dark (1995): (1995), The demon-haunted world : science as a candle in the dark place: New York, publisher: Random House, ISBN: 039453512X, LCCN: 95034076) The 'What it means' explanation text was generated by Google Gemini Flash (accessed January 18, 2026). https://gemini.google.com/app

Tags

#Carl Sagan#evidence#universe#absence#earth#ufos#intelligent#advancement#compelling#impatience#criticized#ignorance
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.