EXTRAORDINARY CLAIMS REQUIRE EXTRAORDINARY EVIDENCEJune 29, 1998
You've probably heard this phrase before, from some stodgy scientist or skeptic who was trying to explain why the testimony of farmer Smith wasn't sufficient evidence to establish that UFO aliens are truly among us. But there seems to be a lot of misunderstanding about what this phrase really means. Specifically, the term "extraordinary" causes a lot of confusion.
I've heard it suggested that an "extraordinary" event is anything outside of normal everyday experience. Gravity happens to everyone, so gravity is "ordinary" - but only a minority claim to have been abducted by UFOs, so UFO abduction stories are "extraordinary", they say. One problem with this interpretation is that it unnecessarily inflates the standard of evidence required for uncommon but real events (such as moon landings and atomic bomb explosions). Likewise, there are experiences which are quite common but are not what they seem. Mirages in a desert are an optical illusion. Everyone who experiences a mirage may think they see water, but it doesn't necessarily follow that it is okay to believe there is water there without demanding some better evidence.
Others say that whether a claim in "extraordinary" or not is entirely a matter of subjective opinion. To the UFO believer, they say, UFO sightings are not unusual at all - and so any evidence will do. On the other hand, they say that a comitted skeptic's subjective rejection of UFO claims places the necessary standard of evidence beyond reach. The problem with this interpretation is that if all claims are only as good as each individual's pre-existing bias about the subject, then it is meaningless to demand any standards of evidence whatsoever. Each ignorant savage is left with the impression that whatever he wants to believe is true, is true - quality of evidence notwithstanding.
A proper understanding of the concept that "extraordinary claims require extraordinary evidence" requires an understanding of its origins. It is a *scientific* concept. Therefor, the issue of "extraordinariness" is meant to be resolved scientifically - not on the basis of everyday experience, and not on the basis of subjective opinion. Scientifically speaking, a claim which (if true) would overturn an idea which has been the subject of numerous scientific tests and appears to be highly reliable is "extraordinary", and one which (if true) fits well within the bounds of established scientific understanding is "ordinary".
For example, walking on the moon and exploding atomic weapons, while not within the bounds of everyday experience, do not violate any established scientific laws and are therefor "ordinary". Angels from heaven, on the other hand, would require an entire new class of heretofor unidentified spiritual phenomena, and would therefor have to be classified "extraordinary".
However, I do agree that this concept does not apply well to all claims of UFO sightings. It is not beyond the bounds of known physical laws to travel between stars, it's just very very very difficult. On the other hand, some of the specific phenomenon cited by UFO claimants *do* violate known physical laws, and must therefor be considered "extraordinary" (for example, aliens who can pass through solid walls).