[Ads-l] extraordinary claims extraordinary evidence

Bill Mullins amcombill at HOTMAIL.COM
Wed Aug 26 02:30:58 UTC 2015

If you google "Extraordinary claims require extraordinary proof", you most often see it (and close variants) associated with Carl Sagan.  He said it in association with his TV show "Cosmos", which was a likely vector for it becoming famous.
And, in fact, the earliest citation I can find for it is from Sagan:
16 Dec 1977 _Washington Post_ Weekend Section p 1 col 3"Extraordinary claims require extraordinary evidence."
But did he originate it?  Marcello Truzzi, a magician, skeptic, and sociology professor (who studied and taught at Cornell, where Sagan also taught) claimed to have coined the expression:"In his famous 1748 essay 'Of Miracles', the great skeptic David Hume asserted that "A wise man...proportions his belief to the evidence,"and he said of testimony for extraordinary claims that "the evidence, resulting from the testimony, admits of a diminution, greater or less, in proportion as the fact is more unusual." A similar statement was made by Laplace, and many other later writers. I turned it into the now popular phrase "extraordinary claims require extraordinary proof" (which Carl Sagan popularized into what is almost the war cry of some scoffers)."http://www.skepticalinvestigations.org/Anomali/practices.html
Truzzi was using the expression at least as early as 1978:http://www.tricksterbook.com/truzzi/ZS-Issues-PDFs/ZeteticScholarNo1.pdf (p. 11)
And the wikipedia article on Carl Sagan credits Truzzi:https://en.wikipedia.org/wiki/Carl_Sagan
as does the obituary for Truzzi in the Mar 2003 issue of _The Linking Ring_ (a conjuror's journal).
So who came up with it?  Truzzi and Sagan were both associated with Cornell, and both were active in the Skeptic movement in the 1970s.  My belief is that one came up with it, the other heard it and started using it, before 1977 (Sagan's first cite).  I don't know if Sagan gets credit now because he actually coined the expression, or simply because he had better press (which he certainly did). 		 	   		  
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