• Carl Sagan’s stumbles

    Carl Sagan, now an icon of science and skepticism, was wrong. A lot. He engaged in pseudoscience and failed to apply scientific knowledge in his own writings. He wrote about epistemology, getting some of that wrong, too. This is not to diminish his accomplishments, nor to suggest Sagan should not be an example to which we should aspire. Exactly the opposite is true. Among the niceties of being nonreligious, is that one can admire heroes without needing them to be flawless as gods. Carl Sagan’s life and writings give us all realistic view of what being skeptical means, occasional stumbles and all. Abstractly “perfect” deities don’t teach us anything about how to be human, but Carl Sagan does. We’re unlikely to sprout wings and join the seraphim, but we can adopt demonstrably useful, positive humanistic and skeptical values. The kind Sagan epitomized.

    I guess I understand Sagan’s appeal. He did make a gold record that’s pretty out of this world.

    The birth trauma theory

    In his essay The Amniotic Universe, Sagan describes what he finds to be salient aspects of birth from the perspective of the baby, citing quack psychiatrist Stanislav Grof:

    • transition from peaceful, serene existence to “panic” state caused by crushing uterine contractions
    • a sense of punishment for no apparent reason
    • the experience of crossing a tunnel-like threshold into a new world

    He suggested that the traumatic experience of birth explains many things, from the foundations of religion to near-death experiences which are triggered memories of the traumatic birth experience.

     I do not know how close the analogies are between personal perinatal experiences and particular cosmological models. […] But the analogies are very close, and the possible connection between psychiatry and cosmology seems very real.

    Sagan uses rather furtive language, at least. Still, we must note this essay is striking failure at applying critical thought. Citing Stanislav Grof is a gross error. This nutjob has been studying “the science of shamanism” for decades, and since the ’60’s at least, has studied psuedoscientific nonsense known as “transpersonal psychology“. It’s hard to understand how a skeptic would take seriously what Grof has to say. It’s like citing Deepak Chopra instead of a Dan Dennett or a Neil deGrasse Tyson.

    Next, all of the psychology is wrong, and it was known to be wrong even when Sagan wrote the essay. The experience of squeezing through a narrow fleshy tube is nothing like serenely floating down a tunnel. There would be no light at the end, either, because a baby’s eyes would be tightly flush with the vaginal wall. Further, humans do not create long term episodic memories before around age two or so. The reason why is obvious, a baby’s brain is still forming, its senses not developed. Information “learned” during this period is not reliable, even if the cognitive bits that do learning even function yet. There is no “repressed memory” to be summoned in moments of stress. Lastly, even if a newborn could somehow form memories of birth, it certainly has no concepts of punishment or moral culpability. These are complex ideas which will require years to master.

    Do extraordinary claims require extraordinary evidence?

    One of Sagan’s best-known quotes is his remarking that the evidence required to prove a claim must equal its a priori likelihood (Sagan did not invent the quote though, it is often credited to Marcello Truzzi and earlier philosophers). Sagan employed this argument specifically in a discussion about extraterrestrial intelligence. The most defensible interpretation of this idea, is that given a particular claim strikes a person as “extraordinary”, then any evidence which is sufficient to compel acceptance of validity of the claim will also be seen as extraordinary. This is true, but it is a statement about psychology, not about evidence. Philosophically, the concept is empty. First, there is no objective meaning of “extraordinary”. Microwave ovens are magic to pre-modern peoples and commonplace to everyone else. A given research paper might seem amazing to a lay reader, but utterly dull to a scientist who works in that field and is knowledgeable about the literature- to them, the paper might merely be an incremental step. Does the standard of evidence then change depending on who we ask? This is clearly false.

    That leads to a second counterargument: shouldn’t a sound epistemology have a single, cohesive standard about what gets counted as “proven”? Multiple standards reek of bias and favoritism, just the things we should not be considering. Either the evidence compels agreement, or it does not. What we think of the claim changes nothing.

    Sagan the agnostic
    Carl Sagan also repeated widely-held, but incorrect views of atheism and agnosticism and generally refused the label “atheist” on the commonly cited grounds—

    To be certain of the existence of God and to be certain of the nonexistence of God seem to me to be the confident extremes in a subject so riddled with doubt and uncertainty as to inspire very little confidence indeed

    I realize that most secularists still accept this shallow reasoning, but I explain why it is not rational here. In short, this defense of agnosticism requires a kind of special pleading and perhaps appeal to ignorance. It is not the case that we must know everything, in order to know anything.

    Candle in the darkness

    Why am I bashing Carl Sagan, and on his birthday? Well, if you’re anything like me, you’ve already been inundated with Sagan adulation and nigh-worship. I think my readers know his many great accomplishments and contributions. Sagan didn’t stand on accomplishments and fame, and wasn’t impressed by them. He emphasized the journey. Progress. The spirit of exploration and growth. He knew, too, that we’re flawed beings whose noble moments are the fleeting reward for a thousand failed attempts. The flawed Carl Sagan, the imperfect human Carl Sagan is infinitely more inspiring to me as a skeptic than the litany of awards or pithy quotes about cosmological wonderment. Here’s what his life teaches me:

    You will sometimes fail in endeavor and in the eyes of your own convictions. Not might; you will. Accepting this as part of life makes it a whole lot easier to catch.

    Embrace your stumblings as opportunities for growth. Sagan was never embarrassed to be wrong.

    There are no masters of skepticism, no mavens of critical thinking. None. You can try your hardest to see yourself objectively. No one can do more, and no one is 100% successful.

    In spite of all of this, you can still do great things and inspire people, which might make it worth all the trouble. Never stop trying.

    So happy birthday, Carl, and thanks. We miss you.

    Category: Critical Thinkingskepticism

  • Article by: Edward Clint

    Ed Clint is an evolutionary psychologist, co-founder of Skeptic Ink, and USAF veteran.
    • Peter

      To me, “extraordinary claims require extraordinary evidence” just means that claims for which there is a low prior will require more evidence before they can be considered probable. The following cartoon summarises this neatly (and is funny) http://xkcd.com/1132/

      But then I am no philosopher and could just be missing something.

      • I just can’t agree with this. Either the evidence can compel reasonable certainty, or it can’t. Nothing about the prior probability has anything to do with this. Our “likely” hypotheses can be wrong. In order to show that they aren’t, we decide a level of evidence is required. We can not lower it because of our initial bias- we can be wrong about that. We can also not raise it because of our initial bias- we can be wrong about that, too.

        Initial “feel” for likelihood is just a guess. It’s always a guess. Guessing is just the thing we need to not be doing in science or skepticism when we are sorting out facts and fictions.

        • Peter

          Hmmm…well I am still attached to it. I suppose it is true that a prior involves a degree of subjectivity, but to the extent this is determined by our individual background knowledge and experiences (rather than just what people want to believe) I think it’s fine. I think it would be reasonable for someone who had experienced some kind of close encounter to require less evidence to believe some other claim about extra-terrestrials visiting earth than it would for me or someone else who hadn’t. So in a sense the evidence required can and should vary from person to person.

          Except in very abstract cases where all probabilities are objectively known, pretty much all judgements involve an element of “feeling”… e.g. the probability of rolling a 6 depends on whether you trust the person who gave it to you not to have loaded it.

          • It might be helpful to consider an example, let’s use the one Sagan was referring to. He was essentially saying that things like eyewitness accounts, radar images, and blurry photos don’t get to count as proof of intelligent ETs visiting earth- even though the same evidence would generally be accepted of a different kind of claim, say, that a 747 flew over a park at a given time.

            In Sagan’s parlance, the former claim is “extraordinary” and the latter much less so, and so the standards of proof diverge. I agree. Now if we consider these two claims more closely, we find that the standard of evidence is actually the same. What makes the 747 claim “ordinary” is the existence of loads of irrefutable evidence: most of us have seen a 747, and probably seen one taking off, perhaps while inside. They’re fixtures of day to day life in the industrialized west. This is all evidence that we add in to our consideration, whether we specifically realize it or not. Had we similar evidence of ET craft, then blurry photos and eyewitness accounts would mean more.

            So is my disagreement just about terms? Maybe, but terms are important. They can obfuscate and confuse. Sagan’s formulation makes it sound like we’re moving the goal-posts for the paranormal claims because we don’t like them when we aren’t (and the UFOlogists have complained about just this point: http://www.debunkingskeptics.com/Page2.htm)

            But also I just find it isn’t clear thinking about evidence. There should be a threshold for accepting claims. Hume perhaps put it best when he said that we should accept a miraculous claim when its falsehood would be even more miraculous. The beauty in that is that you can subtract out “miraculous”, or you can trade it for “extraordinary” without the meaning changing.

            More problems with the Sagan formulation come when we aren’t sure if a claim is extraordinary or not. Many new scientific ideas each year are astonishing or surprising. If they have no analog in our daily lives, they seem more astonishing.. even though they are no less likely for the fact (quantum mechanics, the age of dinosaurs, black holes and quasars, DNA, critters who live on volcanic vents). Instead of wasting time trying to figure out how astonished we should be, we should be asking, what testable predictions are made? What evidence does the claim require to exist?

            • Peter

              Thanks for that. I read that article and I think I see what you mean. However, I think that I would stick to the dictum “Extraordinary claims require extraordinary evidence” and respond to that article in the following ways:

              Firstly, the claim of what constitutes an extraordinary claim is not arbitrary (or shouldn’t be). The reason I would disbelieve a photo of a UFO above a park while I would accept one of a 747 is entirely down to my priors, since the evidence is the same. But in my case the priors include: many photos of UFOs have been shown to be hoaxes, people would have more of a reason to fake this photo than a mundane one, even UFOologists must concede there are more 747s about than UFOs. My response to eyewitness testimony would be similar. If the situation were flipped around and I met someone who was skeptical about global warming who insisted it was just too ridiculous to believe, I would ask him for similar justification for his prior (or, as for most scientific claims, just show him that the evidence is indeed extraordinarily good!).

              Secondly, “extraordinary claims aren’t extraordinary to everyone”, “the claim that land exists would be an extraordinary claim to a fish but not to us”. This is correct in my view. The hypothetical fish they mention would in fact be justified in rejecting reports of land. They seem to think the fish are being unreasonable in doing this- I don’t. Likewise people who have private experiences which I cannot access can hold different prior beliefs about other evidence to me and still be reasonable (though if they are ignoring relevant evidence about hallucinations and sleep paralysis, they are not). However, that’s no reason for me and others who have not had those experiences to consider those claims simply “ordinary”, so I think this objection fails as well.

              You are worried that the word “extraordinary” here confuses people. I can see that might be a problem if you don’t have much time to argue with someone and get your point across. But really, I think that ECREE (or perhaps “MORE extraordinary claims, require MORE extraordinary evidence”) is really just the way we all reason most of the time, so people who we want to think critically will have to learn it some time or other.

    • Our court systems use different standards for evidence,….either “beyond a reasonable doubt” or “by the preponderance of the evidence.” It is idealistic, impractical and a bit naive to think that all truth claims involve the exact same evidence standards since truth claims can go from the mundane to the extraordinary.

      • The court systems are taking into account the consequences for being mistaken in the knowledge the system is not perfect. The standard gets raised because being wrong means an innocent person dies, or is jailed for life (this is where “beyond a reasonable doubt” are employed). This has little to do with epistemology.

        • It has everything to do with epistemology. We as individuals make the same sort of calculations as the court system does. With some things we use one standard with others we use another it depends on the circumstance.

    • Thinka Roo

      Great post, thanks. Love Sagan, but it is true that none of us reach a point where we are finished learning or beyond being corrected in our understanding, and he would never have wanted to be seen in such a light either.

    • Do extraordinary claims require extraordinary evidence? Yes. Philosophically, you end up with word salad.

      Scientific skepticism over the philosophy of science when dealing with matters of scientific skepticism.

      Carl Sagan was certainly wrong about things. A lot of things? Well, you only point to a chapter of Broca’s Brain. So, there’s one thing according to your argument. Why you hold special definitions of extraordinary and evidence, and atheism and agnosticism, isn’t really explained here.

      If it were me, I would have started with Heikegani crabs, and worked my way from there.

      • I don’t think my definitions of any of those things are special. I linked to my discussion of atheism/agnosticism so that the curious can read it in full (and actually the link is to the third of 3 essays on the subject).

    • Ed, I would have to disagree with you on extraordinary claims. I think it is a VERY useful, pragmatic rule of thumb that we all use very often.

      I posted about this here:


      I think it could be expressed in Bayesian form, if I had time to think about it!

    • In defense of Sagan’s defense of “transpersonal psychology”, I’ll point out that Sagan’s writing from the 70s was very influenced by, well, the 70s. Parapsychology and some of the other more far-out ideas in psychology were not understood to be completely beyond the realm of science. Years of debunking, plus the increasing retreat of transpersonal psychology into the wooliness of the New Age movement made its lack of intellectual merit clear by the 1990s.

      I think Sagan was trying to square a rational, scientific, and skeptical world view with a highly pantheistic sentiment about the universe, and it often manifested itself in writing like the Broca’s Brain excerpt shown here.

      • Agreed. One’s intellectual ecology is a substantial influence.