What's that rule-of-thumb for: type of claim needs type of proof?

[The Bear's Key]

I've seen people respond with a rule-of-thumb to a big claim that would turn well established theories on their head.

 

Can't remember it though.

 

Something like: incredible/exceptional/unusual claims need incredible/exceptional/unusual proof.

[Strange]

"Extraordinary claims require extraordinary evidence"

Carl Sagan (in that form)

http://rationalwiki.org/wiki/Extraordinary_claims_require_extraordinary_evidence

[The Bear's Key]

Thanks! My search online had turned up zilch.

[imatfaal]

"Extraordinary claims require extraordinary evidence"

Carl Sagan (in that form)

http://rationalwiki.org/wiki/Extraordinary_claims_require_extraordinary_evidence

 

Shows how good Sagan was - I always assumed it was originanally either from Laplace from a Theory of Probilities or Hume from Concering Human Understanding both of which your link mentions; if you can be confused with those two it demonstrates how well you are doing your job of explaining stuff in an accessible manner. I would have loved to see Sagan in his latter years - he always struck me as so wise and gentle; I can imagine a frail sage-like (yoda-esque?) Carl in his eighties weighing in on the questions of the day with utmost humanity and humility