Extraordinary Claims Require Extraordinary Evidence

Carl Sagan? Marcello Truzzi? Pierre-Simon Laplace? David Hume? Benjamin Bayly? Elihu Palmer? William Craig Brownlee? F. B. Barton? William Denton? Ely Vaughan Zollars? Joseph Rinn? James Oberg? Arthur C. Clarke? Dear Quote Investigator: Tabloid newspapers have printed remarkable claims about alien abductions, mischievous ghosts, bigfoot sightings, and other anomalies. Skeptics have countered these reports by …

Deep Truths Are Statements in Which the Opposite Also Contains Deep Truth

Niels Bohr? Hans Bohr? Werner Heisenberg? Oscar Wilde? Emilio Segrè? Carl Sagan? Anonymous? Dear Quote Investigator: A famous scientist once asserted something like this: The opposite of a deep truth is another deep truth. Would you please help me to find a citation and the correct phrasing? Quote Investigator: In 1949 the prominent physicist Niels …

Tortoises All the Way Down

Hester Lynch Piozzi? William James? Bertrand Russell? Mark Twain? Henry David Thoreau? Carl Sagan? Terry Pratchett? Samuel Purchas? John Locke? George B. Cheever? Joseph F. Berg? George Chainey? John Phoenix? Anonymous? Dear Quote Investigator: According to legend a prominent scientist once presented a lecture on cosmology which discussed the solar system and galaxies. Afterwards, a …

Absence of Evidence Is Not Evidence of Absence

Carl Sagan? Martin Rees? William Wright? William Housman? W. J. Sollas? Dugald Bell? Anonymous? Dear Quote Investigator: The existence or non-existence of intelligent extraterrestrial life is a highly contentious subject. Some thinkers who are open to the possibility of interstellar aliens also believe that the current evidence is inadequate; hence, they advocate using radio telescope …

That Which Can Be Destroyed By the Truth Should Be

Carl Sagan? P. C. Hodgell? Kirien? Anonymous? Dear Quote Investigator: There exists a family of sayings that is popular in the community of skeptics. Here are four examples: 1) That which can be destroyed by the truth should be. 2) Anything that can be destroyed by the truth should be. 3) Anything that can be …

Do Not Be So Open-Minded That Your Brains Fall Out

Carl Sagan? Arthur Hays Sulzberger? Marianne Moore? E. E Cummings? William Allan Neilson? Walter Kotschnig? Samuel Butler? G. K. Chesterton? Max Radin? James Oberg? Anonymous? Dear Quote Investigator: There is a desirable balance between exploring novel ideas with an open mind and maintaining a healthy skepticism. The following humorous cautionary statement exemplifies the tension: Do …

We Are Made of Star-Stuff

Carl Sagan? Albert Durrant Watson? Doris Lessing? Harlow Shapley? Vincent Cronin? Ancient Serbian Proverb? William E. Barton? Anonymous? Dear Quote Investigator: The chemical elements of life such as carbon, magnesium, and calcium were originally created in the interior furnaces of stars and then released by stellar explosions. This fact can be expressed with a beautiful …

Somewhere, Something Incredible Is Waiting To Be Known

Carl Sagan? Newsweek Reporters? Sharon Begley? Apocryphal? Dear Quote Investigator: Today on the website of a software developer I saw an inspiring quotation that was credited to the famous astronomer and science communicator Carl Sagan: Somewhere, something incredible is waiting to be known. I would like to use this quotation also, but I have not …