The aphorism was made popular by astronomer Carl Sagan.[2] Others have put forward this idea but phrased it differently. Pierre-Simon Laplace (1749–1827) said "The weight of evidence for an extraordinary claim must be proportioned to its strangeness".[3] In 1808, Thomas Jefferson also said "A thousand phenomena present themselves daily which we cannot explain, but where facts are suggested, bearing no analogy with the laws of nature as yet known to us, their verity needs proofs proportioned to their difficulty."[4] In "On the Extraordinary: An Attempt at Clarification" (1978), sociologist Marcello Truzzi said "an extraordinary claim requires extraordinary proof."[5]