# Extraordinary Claims, Extraordinary Evidence, And Why We'll Never Agree **URL:** \ **Category:** Great Debates\ **Created:** [November 26, 2011, 3:09pm UTC](https://boards.straightdope.com/t/extraordinary-claims-extraordinary-evidence-and-why-well-never-agree/604147 "2011-11-26T15:09:18Z")\ **Posts on this page:** 4\ **Page:** 3
**Author:** ![Half\_Man\_Half\_Wit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/half_man_half_wit/32/21766_2.png) [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)\ **Post date:** [November 30, 2011, 6:39pm UTC](https://boards.straightdope.com/t/extraordinary-claims-extraordinary-evidence-and-why-well-never-agree/604147/41 "2011-11-30T18:39:11Z")
> [@Frylock](#): > > For one thing, it could be that we’re “designed” (in a broad evolutionary sense) such that these coincidences of data and priors tend to work out for us, collectively, in the long run. If that’s plausible, then it gives us a basis to trust the “coincidence of it all” to some extent. Hmm, how’d you design (in the same sense) that? Seems to me you’d run into the problem of having to expect the unexpected… > [@](#): > > For another thing, (completely separate from the prior speculation,) it could be that this problem simply serves to highlight the _collective_ nature of scientific endeavors. You and I, as individuals, are not actually rationally justified in taking our substantial agreement to be evidence for the truth about what we agree about. Nevertheless, the more-or-less formal practice of actually doing measurements, calculating probabilities, etc., issues forth in a collective endeavor that _is_ truth-oriented as a whole, over time. I think I had something a lot more eloquent and clear to say about that but between the time I started writing and the time I’m writing this I had a student come in for help and everything in my head kind of went away… I think I’m kinda sympathetic to this view – there can be organized behavior emerging from essentially random, directionless dynamics, see things like swarm intelligence etc. Also, somewhat more mundanely, there’s the ‘wisdom of crowds’-effect: as long as we’re equally likely to be wrong in all directions alike, the mean will tend to be dead on. For another nother thing, perhaps this is just an indication that ultimately, one has to kick away the ladder – that in the end, there’s no consistent method to arrive at some element of truth, and that all the method there is can be at best applied to judging the validity of beliefs; i.e. that justification is not sought in how one comes to a belief, but rather, in how well that belief holds up. Most of the contentious issues of method, in particular the scientific one, lies, I think, in the generation of hypotheses; maybe one can escape this by instead focusing on validation. ---
**Author:** ![SiXSwordS](https://avatars.discourse-cdn.com/v4/letter/s/49beb7/32.png) [@SiXSwordS](https://boards.straightdope.com/u/SiXSwordS)\ **Post date:** [November 30, 2011, 8:28pm UTC](https://boards.straightdope.com/t/extraordinary-claims-extraordinary-evidence-and-why-well-never-agree/604147/42 "2011-11-30T20:28:29Z")
> [@ianzin](#): > > Extraordinary claims require extraordinary evidence"… gets recycled a lot just because it’s attributed to Carl Sagan, How do you know why it gets recycled. I had heard the phrase many times before hearing it attributed to Sagan. I would assume it is somewhat idiomatic, like head over heels. You can point out that the words don’t make sense as they’re arranged, but shorthand can be very useful. If we can readily exchange the more verbose version for the idiomatic version then the pithy version is useful in conveying the meaning quickly and memorably. > [@](#): > > Evidence does not come in two flavours: ordinary and extraordinary. If anyone thinks otherwise, I’d like to see which litmus test you apply to distinguish one from the other. I think I see what you’re saying, and while I don’t have a litmus test I do think there is a common sense distinction to be made. Imagine two pieces of evidence. The first: A pile of rat feces found in a basement. The second: A verbal transmission from extraterrestrial life forms. The first would seem to be ordinary and the second extraordinary. > [@](#): > > [S]keptics keep recycling the quoted version, even though it’s nonsense, because they’ve seen it attributed to Carl Sagan and therefore feel it must contain great wisdom that mustn’t be challenged or corrected (much like religious followers won’t challenge any piece of scripture, even when it’s completely bonkers). You seem to be doing a lot of mind reading. I think people keep using the phrase because it adequately describes the fact that there is a difference between claiming one’s tea has gone cold and claiming that Jimmy Hoffa was an alien and has been living in one’s attic since 1975. ---
**Author:** ![Half\_Man\_Half\_Wit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/half_man_half_wit/32/21766_2.png) [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)\ **Post date:** [December 1, 2011, 7:06pm UTC](https://boards.straightdope.com/t/extraordinary-claims-extraordinary-evidence-and-why-well-never-agree/604147/43 "2011-12-01T19:06:29Z")
> [@SiXSwordS](#): > > I think I see what you’re saying, and while I don’t have a litmus test I do think there is a common sense distinction to be made. > > Imagine two pieces of evidence. The first: A pile of rat feces found in a basement. The second: A verbal transmission from extraterrestrial life forms. > > The first would seem to be ordinary and the second extraordinary. It’s perfectly ordinary evidence, just for an extraordinary hypothesis. Of what other kind would you expect evidence for the existence of intelligent extraterrestrial life to be? It would all seem quite Earth-shattering, but not because of any special quality of the evidence. ---
**Author:** ![SiXSwordS](https://avatars.discourse-cdn.com/v4/letter/s/49beb7/32.png) [@SiXSwordS](https://boards.straightdope.com/u/SiXSwordS)\ **Post date:** [December 1, 2011, 8:54pm UTC](https://boards.straightdope.com/t/extraordinary-claims-extraordinary-evidence-and-why-well-never-agree/604147/44 "2011-12-01T20:54:05Z")
> [@Half\_Man\_Half\_Wit](#): > > It’s perfectly ordinary evidence, just for an extraordinary hypothesis. Methinks you doth parseth too much–as it were. Does the scientific process really depend on where we put the adjective? …assuming of course that you’re talking about the rat feces. [Previous page](https://boards.straightdope.com/t/extraordinary-claims-extraordinary-evidence-and-why-well-never-agree/604147.md?page=2)