Freethinker Sunday Sermonette: tales from the trenches

For example, Carl Sagan's remark that extraordinary claims require extraordinary evidence. I'm not even sure what that means but I see no reason why it should be true.

Really?  This is why - Extraordinary Claims Require Extraordinary Evidence

Skeptico: Thanks for the link and the nice post. However my response would be that to define extraordinary claims in this way makes the requirement for extraordinary evidence a tautology. Suppose I made the extraordinary claim that I could fly. You want some evidence. So I fly for you. That's evidence and you may believe it is extraordinary that I am able to fly, but does that make it extraordinary evidence or just evidence? You may require an explanation for what you see because you are so surprised. The explanation may reveal something ordinary (I cheated) or that you can find no explanation or something entirely new in science. But most research is meant to reveal things that are entirely new.

The problem with the Sagan quote is that it is too glib and when you start to unpack it it becomes necessary to qualify it, modify it, explain it and so on (which is what you did, so ably). That doesn't mean there isn't a sense in which it reveals an important truth (although I am not sure what that is in general), but that as a clichè it is superficial. Which is the (apparently) extraordinary claim I made.

Thanks for the link and the nice post. However my response would be that to define extraordinary claims in this way makes the requirement for extraordinary evidence a tautology.

Why?  Whatâs your definition of âtautologyâ?

Suppose I made the extraordinary claim that I could fly. You want some evidence. So I fly for you. That's evidence and you may believe it is extraordinary that I am able to fly, but does that make it extraordinary evidence or just evidence?

If it also explains why humans are not ordinarily able to fly, then it would be extraordinary evidence.  Extraordinary evidence will account for the abandoned claim (that people canât fly), while also explaining the new one.  If cheating could not be ruled out (eg I was unable to check for wires, or camera tricks) then it would not be extraordinary evidence. Why is that tautology?

You may require an explanation for what you see because you are so surprised. The explanation may reveal something ordinary (I cheated) or that you can find no explanation or something entirely new in science. But most research is meant to reveal things that are entirely new.

Yes but if the entirely new thing completely contradicts what we knew before, the evidence will need to explain what we thought before as well as the new thing.

The problem with the Sagan quote is that it is too glib

Why is it glib?  What is your definition of âglibâ?

and when you start to unpack it it becomes necessary to qualify it, modify it, explain it and so on (which is what you did, so ably).

Whatâs wrong with explaining something?  Why would having to explain something mean the thing was glib?  Your posts explaining why we should get the flu vaccine - are they glib too?

That doesn't mean there isn't a sense in which it reveals an important truth (although I am not sure what that is in general), but that as a clichè it is superficial.

âas a clichè it is superficialâ?  And you accuse me of tautology? I'll tell you what is superficial. It's this:

Carl Sagan's remark that extraordinary claims require extraordinary evidence. I'm not even sure what that means but I see no reason why it should be true.

You don't understand Carl Sagan's statement that extraordinary claims require extraordinary evidence?

Let me give you an example. If I were to say to you that when I drove home from work today I got green lights all the way, not hitting one red light, you'd probably accept me at my word. If I then stated that all this week the same thing happened, you'd probably say "Really?" in a disbelieving tone and have a doubt in your mind. Perhaps you might believe it if my commuting partner, a neighbour, corroborated my claim.

If I then stated that for the past 7 years I've never had to stop at a red light, that every time I approach it is either green or it turns green before I get there, I think you'd call bullshit and say that you'd only believe that if I had a camera in my car and that even then, you'd need to know that the camera was tamper proof so that I didn't doctor the recordings.

I think anyone older than a small child would understand this example and I think it encapsulates the thought neatly.

Now I won't claim that an unseen all-powerful being responded to my silent pleadings to change red traffic lights to green, but if I did, would you require less or more evidence that such was the case?

skeptico: I said it was a tautology because your definition of extraordinary evidence included the notion that it was evidence to back up an extraordinary claim. Your further explication requires buying into a particular view, akin to Quinean pragmatism, that itself reqjuires explication and isn't universally accepted (it happens to appeal to me, I admit). In essence what I was saying is this: when you look under the hood of the Sagan quote you find a rather complex mechanism with lots of difficult loose ends. It was a casual comment on my part, but you have every reason to call me on it and request an explanation for why I said it.

Bruce: Actually, people accomplish that extraordinary feat every day by adjusting the speed of their driving to the timing of the lights. To me that implies at least two things: that the explanation is not extraordinary; and that the non-extraordinary explanation means that the claim itself was not extraordinary. This is a typical example of modus tollens in logic and is related to my reply, above, to skeptico..

I said it was a tautology because your definition of extraordinary evidence included the notion that it was evidence to back up an extraordinary claim.

My post was an explanation of why Extraordinary Claims Require Extraordinary Evidence â the explanation was not âit was evidence to back up an extraordinary claimâ - a rather glib dismissal on your part.   My post explained WHAT an extraordinary claim is and WHAT extraordinary evidence is and WHY one needed the other. You can disagree with those explanations if you want, but detailed definitions of those terms and explanations for their relationship are not tautologies.

Your further explication requires buying into a particular view, akin to Quinean pragmatism, that itself reqjuires explication and isn't universally accepted (it happens to appeal to me, I admit). In essence what I was saying is this: when you look under the hood of the Sagan quote you find a rather complex mechanism with lots of difficult loose ends. It was a casual comment on my part, but you have every reason to call me on it and request an explanation for why I said it.

So if something requires an explanation then thereâs something wrong with it?  That makes it âglibâ?  Then I guess if you say I should get the flu vaccine then that statement is âglibâ if it requires an explanation (how do vaccines work), or if there are complexities (the vaccine doesnât work on everyone)?  

You started off by saying you didnât understand why extraordinary claims require extraordinary evidence.  Fair enough.  You donât have to understand everything (I certainly donât).  Thatâs why I cited my post with the explanation.  Your response, rather than to say why my explanation is wrong, was to say it was tautology (it isnât) or that it shows the issue is complex (I know â thatâs why I wrote the post) as though that somehow invalidated it. 

Bruce: Actually, people accomplish that extraordinary feat every day by adjusting the speed of their driving to the timing of the lights.

Really?  âPeopleâ according to you, have never had to stop at a red light in 7 years, just by adjusting the speed of their driving to the timing of the lights?  In 7 years?  Are you deliberately trying to miss Bruceâs point?  Bruce wrote, âI think anyone older than a small child would understand this exampleâ¦â  I agree.  And yet you still managed to misunderstand it.

David Hume wrote that "a miracle is a violation of the laws of nature" and "no testimony is sufficient to establish a miracle unless the testimony be of such a kind that its falsehood would be more miraculous than the fact which it endeavours to establish." Hume's full essay on the topic of miracles is a mouthful, to say the least. I think Sagan's summary is brilliant. Massimo Pigliucci wrote a nice article in the Skeptical Enquirer in 2005, reprinted in the book Science Under Siege, which describes the idea in a Bayesian framework (sadly it's not available online).

skeptico: Wow. Capitals = yelling. Let's cool down. First, I said that merely quoting Sagan's aphorism, as does Wise Monkey, is glib. Obviously (to me, anyway) I wasn't saying you were glib. You took the time and trouble to write an extended essay on the topic. Second, I was pointing out that lots of the automatic responses we skeptics give (and I don't think my credentials as an atheist are at issue here) are, when looked at closely, considerably less obvious and controversial than we give them credit for, not because the religious are correct but because the issues are more subtle. It's OK to say you agree completely with Sagan on this, if that's what you believe, but it's not OK to say it's the last word on a difficult subject in both epistemology and metaphysics for reasons that have no relation to religious belief. It's fine, also, to quote Hume (who is one of my intellectual heroes) but not to pretend that his solution to the problem of induction is the last word, either. Scientists and philosophers of science have been arguing about it since his time (and before you start yelling at me for accusing you of saying his approach to induction is the last word, I am not; I am making a point about appeals to authority, when what is being contended have a long subsequent history of argument and controversy). As for the red light, I misread it as 7 days, but that doesn't really matter as it is quite conceivable someone could master the timing and if they did, this would no longer be considered extraordinary evidence but just an explanation of an unusual skill or knowledge of the timing sequence. My additional point, was that if this is true (that it would no longer be considered an extraordinary claim once explained) then the contrapositive means that lack of extraordinary evidence implies lack of extraordinary claims, i.e., that it is a tautology. Feel free to disagree.

skeptico: Wow. Capitals = yelling. Let's cool down.

Donât be silly.  Capitals were for emphasis.

First, I said that merely quoting Sagan's aphorism, as does Wise Monkey, is glib.

Perhaps it is, if the person quoting it does it without understanding it.  Which is why I wrote my explanation.  But you went on to imply that when you try to explain it (ie not just use it glibly) then somehow this means it isnât true, or is less true or something (actually I'm not 100% sure what you did mean, anymore).  Regardless of how it is quoted, I believe I have shown it is valid.

Obviously (to me, anyway) I wasn't saying you were glib. You took the time and trouble to write an extended essay on the topic. Second, I was pointing out that lots of the automatic responses we skeptics give (and I don't think my credentials as an atheist are at issue here) are, when looked at closely, considerably less obvious and controversial than we give them credit for, not because the religious are correct but because the issues are more subtle. It's OK to say you agree completely with Sagan on this, if that's what you believe, but it's not OK to say it's the last word on a difficult subject in both epistemology and metaphysics for reasons that have no relation to religious belief.

Iâm not saying that itâs âthe last wordâ on anything, am I?

As for the red light, I misread it as 7 days, but that doesn't really matter as it is quite conceivable someone could master the timing and if they did, this would no longer be considered extraordinary evidence but just an explanation of an unusual skill or knowledge of the timing sequence.

Yes but only if Bruce had a relatively short journey each day on a road with synchronized lights, and he never went anywhere else.  Sorry, but I think youâre being deliberately dense here.  Bruceâs example was quite clear; you seemed determined to misunderstand it.

My additional point, was that if this is true (that it would no longer be considered an extraordinary claim once explained) then the contrapositive means that lack of extraordinary evidence implies lack of extraordinary claims, i.e., that it is a tautology. Feel free to disagree.

That is pure nonsense.  Nowhere have I said (and there is no reason I can think of to say) that lack of extraordinary evidence implies lack of extraordinary claims.  In fact, it is clearly not true â homeopathy has no extraordinary evidence to support it and yet it is an extraordinary claim.

skeptico: You seem to be very clear that my remarks were about you. It's not about you (or me). In fact the post was about just what I said it was: an observation that skeptical counter arguments are often more problematic than we assume but that both sides have settled into a more or less routine kind of trench warfare. It was an observation, not a detailed analysis. It seemed to have gotten under your skin, somehow. I didn't have you or anyone in particular in mind except for the Wise Monkey clip.

Regarding the comment about the lights, while I misread Bruce's comment, I was amplifying a comment of my own, not yours or his (memo: not everything is about you). What I was saying is this. If upon hearing that the evidence for what appears to be an extraordinary claim is not really very extraordinary at all (and the traffic light is as good an example as any), then the tendency of many people (translation: me, at the very least) is that the claim itself wasn't very extraordinary now that I understand what is involved. By contraposition, that means that extraordinary claims imply (in the logical sense) extraordinary evidence, hence it is a tautology (I'm using the words in the technical logical sense). Your homeopathy example show's you didn't understand what I said. The argument depends on the fact that there is evidence but it is not considered extraordinary and you gave me an example where there is no evidence, extraordinary or otherwise. BTW, except for acronyms (like BTW or WTF), capitals on the internet is shouting. Minor issue.

skeptico: You seem to be very clear that my remarks were about you. It's not about you (or me).

Well, you did write:

â¦my response would be that to define extraordinary claims in this way makes the requirement for extraordinary evidence a tautology.

I presumed that by âin this wayâ you meant by the way I had defined it in the link I provided that you were replying to.  Are you now saying that my explanation of âextraordinary claims require extraordinary evidenceâ was not a tautology? 

Regarding the comment about the lights, while I misread Bruce's comment, I was amplifying a comment of my own, not yours or his (memo: not everything is about you).

Where did I say it was about me?

What I was saying is this. If upon hearing that the evidence for what appears to be an extraordinary claim is not really very extraordinary at all (and the traffic light is as good an example as any), then the tendency of many people (translation: me, at the very least) is that the claim itself wasn't very extraordinary now that I understand what is involved.

Assuming you could really find a stretch of road where you could always avoid a red light (which I donât believe for a minute â but just for the sake of argument, letâs say there is such a stretch where we both agree you can avoid the red light):

â¦the claim is not extraordinary because the claim has now changed to one that we both agree is not extraordinary.  Itâs not extraordinary because you now know there is already extraordinary evidence for it (in our hypothetical â since we agreed this stretch of road exists).  As I wrote in my post:

â¦most "ordinary" claims are already backed by extraordinary evidence that you donât think about

Itâs not that âthe evidence for what appears to be an extraordinary claim is not really very extraordinary at allâ as you wrote; it is the exact opposite: that the evidence actually is extraordinary.  (Assuming this stretch of road did actually exist.)  You just didnât know it initially because you misunderstood what the claim actually way (actually, you changed the claim to one that Bruce didnât mean â one that was less extraordinary).

By contraposition, that means that extraordinary claims imply (in the logical sense) extraordinary evidence, hence it is a tautology

Absolute bullshit.  An extraordinary claims does not imply extraordinary evidence.  Thatâs nonsense â if that were so, every extraordinary claim would be true.

I explained this quite clearly:

When we say âextraordinary claimsâ, what we actually mean are claims that do NOT already have evidence supporting them, or sometimes claims that have extraordinary evidence against them.

How is that statement tautological?  (Note, the uppercase ânotâ in the above is for emphasis â it is to highlight the word you seem to be missing that means I am saying the opposite of what you wrote.) 

(I'm using the words in the technical logical sense).

And what on earth does that mean?

Your homeopathy example show's you didn't understand what I said.

No, it shows you donât understand this subject. 

The argument depends on the fact that there is evidence but it is not considered extraordinary and you gave me an example where there is no evidence, extraordinary or otherwise.

Actually there is evidence for homeopathy (homeopaths will quote you studies and case histories), just not very good evidence.  Not extraordinary enough.  And thatâs the point.

No, it shows you donât understand this subject.

I'm not sure what the subject is any more, but I do understand what a tautology is. You may wish to look it up. It is a term used in symbolic logic.

I'm not sure what the subject is any more, but I do understand what a tautology is. You may wish to look it up. It is a term used in symbolic logic.

I know what a tautology is.  I asked you to justify your claim that my explanation of âextraordinary claims require extraordinary evidence,â is a tautology.  I note that you canât.

OK guys, cut it out!!! I'm a long time reader of both your blogs, but I never comment. My grandchildren just left from an extended holiday visit. I feel like they just came back! You two are arguing over nothing! I'm sure the religious folks are getting a big kick out of this.

lurkeratheisgramma: LOL. I know how you feel. I love the first ten minutes of the grand children's visit.

OK. For my part, I'll knock it off. As you point out, on the essentials, skeptico and I are on the same page. Skeptics are skeptics because we like to argue. I actually thought skeptico's post was pretty good.

So, tell me, if you would, do you two open your boiled eggs from the large end or the small one?