Ricochet is the best place on the internet to discuss the issues of the day, either through commenting on posts or writing your own for our active and dynamic community in a fully moderated environment. In addition, the Ricochet Audio Network offers over 50 original podcasts with new episodes released every day.
Halloween Horror: Rhetoric, ESP, and the Other Guy’s Zombie Army
What kind of evidence would it take to persuade you that ESP exists? We skeptics say it would take extraordinary evidence. And yet, were we presented with extraordinary evidence, chances are good we’d disbelieve it. That’s irrational, right?
Not necessarily.
Bayesian Prior-ities
We intuitively form initial estimates of how plausible a claim might be, estimates quantifiable as prior probabilities. When we’re reasoning correctly in a Bayesian fashion, we assign extraordinary claims very low prior probabilities. Not exactly zero, since a prior probability of exactly zero implies that no evidence, however great, could change our mind, and extraordinary shouldn’t mean impossible. But close enough to zero to count as zero for most purposes – although not when we’re asked to re-evaluate the claims themselves.
Classical statistics typically employs a null hypothesis and one alternative hypothesis to evaluate data. The human brain, though, can juggle multiple alternative hypotheses, with experience intuiting each alternative’s prior probability – a measure of its plausibility even before it’s tested against the data collected. Drawing prior probabilities from experience and correctly updating them in light of new evidence is the essence of Bayesian rationality.
When claims already comport with our experience, we naturally – and rationally – won’t disdain evidence supporting them. When a claim seems extraordinary to us, though, we trot out the demand “extraordinary claims require extraordinary evidence.”
The seeming paradox – and evidence of our gross irrationality to those trying to convince us – is that we may persist in our disbelief even when given the extraordinary evidence we requested! Life teaches the sad lesson that people’s beliefs won’t necessarily converge when presented with identical evidence, but may, confoundingly, diverge further. Irrational! Identity-protective cognition! Motivated reasoning! Human perversity!
Not so fast. As physicist and Bayesian scholar ET Jaynes observes, this divergence may be entirely consistent with correct Bayesian reasoning on differing priors.
Evidence, or Reporting Errors?
Jaynes notes we rarely experience evidence directly. Instead, we rely on others’ reports of evidence. One possibility lurking in the back of our minds is that those reports contain reporting errors. What if they’re biased, perhaps through cognitive or publication bias? What if their data was (however inadvertently) cherry-picked? Might we suspect extraordinary evidence is only extraordinary because of experimental error? Might we even suspect deliberate deception?
Not only might we, but the more extraordinary reported evidence seems, the more we should suspect reporting error, and perhaps outright chicanery. It’s reasonable to suspect reports that “seem too good to be true.” Even in high-trust environments where suspicion of reporting error is low, when the likelihood of an extraordinary claim strikes us as even lower than the likelihood of reporting error, all that extraordinary evidence supporting the claim does is bolster our suspicion of reporting error, rather than persuading us of the claim.
Jaynes calls reporting error “deception,” even when it’s unintentional. In “Queer uses for probability theory,” a rollicking chapter in applied mathematics (fellow nerds may begin page 149 of this PDF), Jaynes discusses the famous Soal experiment in ESP and why “this kind of experiment can never convince” him of a person’s telepathic powers
…not because I assert [the probability of telepathic powers] = 0 dogmatically at the start, but because the verifiable facts can be accounted for by many alternative hypotheses, every one of which I consider inherently more plausible… and none of which is ruled out by the information available to me.
Indeed the very evidence which the ESP’ers throw at us to convince us, has the opposite effect on our state of belief; issuing reports of sensational data defeats its own purpose. For if the prior probability of deception is greater than that of ESP, then the more improbable the data are on the null hypothesis of no deception and no ESP, the more strongly we are led to believe, not in ESP, but in deception. For this reason, the advocates of ESP (or any other marvel) will never succeed in persuading scientists that their phenomenon is real, until they learn how to eliminate the possibility of deception in the mind of the reader.
Brains! Brains! (Zombie Hypotheses)
When extraordinary evidence is cited to support an extraordinary claim, the evidence may inadvertently resurrect a skeptical brain’s “dead hypotheses” instead, “dead” because the brain estimates their likelihood at near zero – but still not as close to zero as the estimate that brain assigns to the extraordinary claim. I call these dead hypotheses “zombie hypotheses,” since they spring back to life in the face of the extraordinary to feast on skeptical brains.
Jaynes observes zombie hypotheses attack even in high-trust environments, and even when the extraordinary claim is true and the evidence supporting it valid. Such zombie attacks have
…made us aware of an important general phenomenon, which has nothing to do with ESP; a person may tell the truth and not be believed, even though the disbelievers are reasoning in a rational, consistent way.
If zombie attacks occur even in high-trust environments among people of similar backgrounds, how much more likely are they in politics, where trust is lower, people’s backgrounds differ, and people routinely suspect the “deception” of not only innocent reporting error, but also of subterfuge?
Perhaps it’s no accident that political discourse often devolves into prompting the other guy to resurrect an army of zombie hypotheses, then concluding from the sheer number of zombies he summons that he must be crazy, flagrantly rationalizing, or both. Else why would he attack our reasoning with so many mythical monsters? That he may also be reasoning correctly, given his experience, and his zombie army might be evidence of this, is almost too horrible to contemplate.
The Ungrateful Undead
“You and what army?” we’re sometimes tempted to demand of opponents. Their zombie army – the army of hypotheses they find more plausible than our claim, no matter how extraordinary our evidence – that’s who. Evidence cannot be interpreted except in light of prior beliefs. And because two people’s prior beliefs may differ
…probability theory appears to allow, in principle, that a single piece of new information D [D for “data”] could have every conceivable effect on their relative states of belief.
Data never absolutely supports or refutes any claim, but only supports or refutes it relative to all the other (“prior”) information we have. When our prior knowledge differs, the same data that supports a claim for one of us may refute it for another – maddeningly, without logical error on either side.
[D]ivergence of opinions is readily explained by probability theory as logic, and that it is to be expected when persons have widely different prior information.
Although we hope – and often find – that the more data we share, the more our beliefs converge, it’s logically possible for data sharing to drive two reasoner’s beliefs farther apart without either erring logically. Now, possible isn’t the same as likely. Many of us suspect this possibility is nonetheless extremely implausible. There’s something too morally lazy – or simply too horrifying – about supposing this possibility manifests often enough in real life to justify much human agreement.
Zombie hypotheses would be far less terrifying if they were just bad-faith hypotheses resurrected in order to deny reason. The real horror of zombie hypotheses, especially for political consensus, is not that they’re a defense mechanism against reason, but that they’re baked into what reasoning is.
Is There Hope?
Carl Sagan famously described the world of insufficiently-skeptical brains as demon-haunted. ET Jaynes suggests that skeptical brains, while perhaps not haunted by demons (though I suspect all brains are, more or less) are at least prone to zombie infestations. When mutually-skeptical minds are busy attacking one another with hordes of ungrateful undead, is there any hope? Any way to stop the zombies? Yes, at least sometimes. It was alluded to earlier:
For this reason, the advocates of ESP (or any other marvel) will never succeed in persuading scientists that their phenomenon is real, until they learn how to eliminate the possibility of deception in the mind of the reader.
Jaynes continues, citing a diagram illustrating that
the reader’s total prior probability for deception by all mechanisms must be pushed down below that of ESP.
Pushing a skeptic’s estimate of the total likelihood of “deception by all mechanisms” below his estimate of the likelihood of your claim means establishing trust. Many effective techniques for establishing trust rely on something other than “cold reason.” Some techniques are not even honest (the con in con-man is short for confidence, after all). Rhetoric, for example, need not be used honestly. Rhetoric aims to persuade, and while persuasion requires establishing trust, the very possibility that rhetoric works well enough at establishing trust that it’s useful for establishing unwarranted trust puts the trust-building power of rhetoric under suspicion. Few humans are immune to the blandishments of rhetoric from someone, but when someone strikes us as untrustworthy enough to begin with, the hypothesis that their rhetoric is a confidence trick is often very undead indeed.
In today’s political climate, it’s easy to believe that establishing trust often isn’t feasible. And there’s no guarantee that it must be – indeed there’s a possibility, however slight, that it might be logically impossible.
Jaynes is not the first to observe that high trust among scientists is what enables scientists to keep the zombie hordes at bay long enough for sharing data in common to forge knowledge in common. This process goes by simpler name, learning. Without trust, there’s little hope for even the most rational of arguments to produce learning.
This essay is based off an earlier draft, published just after Halloween last year.
Published in Science & Technology
Brains contain no semantic content. That doesn’t have much to do with your argument, I just think it’s imprecise (or more precisely false) to attribute semantic content to something that contains none. I suppose you could just replace every instance of brain in this post with mind or simply admit that you don’t believe in the existence of semantics…which is hard to do since we both know your mind and my mind has loads of semantic content.
Aside from that look into the contemporary debate over contextualism, and also check out Reformed Epistrmology vis a vis Plantinga. Those are related to some of this. Bayesian seems strange and boring to me so I don’t have much to say about it. Bayes Theorem came up maybe once during my philosophy studies in college and grad school.
TBH I didn’t understand much of this, I want to revisit your post later and think about it some more.
You didn’t tell me there was going to be math.
This is excellent. All too often I wonder how some of my very intelligent and liberal friends can have such radically different points of view on issues when I know that we’re all considering the topics in a rational manner. (This is opposed to the many people I know who are not considering issues rationally.) I’m sure they wonder the same thing about me. This essay does a wonderful job of addressing not just why those differences exist but how they can be overcome by establishing trust. And if there’s anything our current political environment does well it’s encouraging trust and understanding between people with different priors! Or just the exact opposite of that. In any case, thanks for writing this. I look forward to it inspiring some productive discussions in the future.
Well… zombies… Zombies like brains… brains… :-)
More seriously, I’m unsure of what you mean by brains containing no semantic content. There is certainly much we don’t understand about how brains embody mind, but it would seem to me there is reasonable evidence that they do. It seems reasonable to expect a change in mind to correspond to some change in brain state.
I have ESP… N.
I’ve seen it. It’s like he has a fifth sense.
My mom had extremely chilling and accurate ESP episodes, always having to do with one of her children. There was just no other explanation for these events.
There is absolutely no question about it, Right Angles. My father’s side of the family passed it down. My son – an astrophysicist/space scientist knows it exists. Serious researches call it PSI.
You have to experience it to know that there is absolutely no other explanation.
Here’s a light-hearted example. Our son’s cousin came walked into the Christmas celebration with a wrapped gift for his mother and chuckled and said ” You’ll never guess what this is.” My son didn’t even touch the package. Grabbed a pencil and paper and drew the darndest image. None of us had even seen one before. Wish you could sit around with us while he does remote viewing. (Guessing things we’ve placed in a paper bag)
Whoa.
Whether it’s ESP or something else, personal experience can be a powerful way to establish trust, yes.
Even when you trust someone is reporting their experience honestly, a second or thirdhand report leaves a lot of questions unanswered that might be answerable if the experience happened directly to you, or to a loved one you know very well.
Nice article on how belief works.
I am on the skeptic side on ESP for this reason: If it were true, it would have changed the course of history. It has not. (hat tip to Larry Niven)
I’m reminded of the “real killer” in the O.J. Simpson case. It’s not impossible, just highly implausible.
Could plainness be a part of it?
This is a bad example — not in the least because it was actually masking a deception — but it puts me in mind of “the ball trick” in The Prestige. Basically, the trick was compelling because it was so un-flashy.
Could you explain “the ball trick”?
If I’m following you, then yes, evidence that is too flashy is by itself problematic. For example, Jaynes mentions:
As he said, it would have been more plausible to other researchers if he and his doctoral student Bretthorst had found their method only produced 50% improvement.
Now, he and his student were not in a position to softpedal their evidence, calling it 50% improvement when it wasn’t just because 50% was a more plausible figure. They had to give the estimate of improvement they really got, and as a result, they had to be extra-scrupulous with their fellow scientists to be believed.
In less quantitative, more qualitative matters, it’s easier to understate something without doing violence to the truth (or leastaways not much violence), if it seems the understatement is more likely to be believed than a flat statement of what you believe is really going on.
I can’t imagine how any scientist could explain away the things my mother did.
Because people’s egos are often wrapped up with what they believe to be true, or what they state their motivations are for how they behave, I frequently have to softpedal hard truths and concrete instructions to my employees. There are times when I have to sound like I’m merely suggesting that they investigate the faintest possibility that they are wrong, and then let them do the mental work to get there. People trust their own experiences more than the experiences of others anyway, and when it sounds like you are threatening their very reasoning, they get their hackles up and refuse to budge. It all comes down to trust, and people nearly always trust themselves first.
How do you know?
How could you know?
(The Phantom Epistemologist strikes again!)
What does it say about me that I would have understood it better if there were more math?
Once in junior high health class, we were playing a poor man’s version of Pictionary on the chalkboard to close out our unit on drugs, in which all the topics were drug-related. After a few rounds of people drawing internal organs or hypodermic needles on the board, the next person grabbed a word out of the hat looked completely stumped, with obviously no idea how he was going to draw the item. Within one second I blurted out “emphysema!” and of course it was the correct answer. See, I have ESPN 2.
A little bit off the subject: This is one reason it is so difficult, actually impossible, to convince a mentally ill person that his or hallucination isn’t real. We believe our interpretation of our perceptions–perceptions defined as sensory input of any kind.
We’ve had some excellent discussions of this topic and related topics in the past.
Here is one started by Arahant.
Here is one started by Trink.
Real ESP would give people with it an edge. A strong edge. Men with it would have more kids than men without it. It would be something we would have to account for.
If the powers do exist, they are so ineffective as to be meaningless.
It tells me you might enjoy reading the original and working through Jaynes’s problems :-)
Here is the PDF of the whole book. This particular chapter starts on page 149. (I trust that, if you find the book valuable and don’t already have a copy at your home, office, or school, you’ll eventually get a copy – we have a copy and have even given a copies as wedding gifts, and we still find the PDF useful.)
My husband and I were talking about this in the car, and there is something in the “Queer uses” chapter we’d like to check. It’s a great book, but published posthumously, so some irregularities, although fans of it are good at publishing errata online.
http://www.skepticforum.com/viewtopic.php?t=21485
Uh, huh.
If you don’t mind my using just what you’ve laid out here as an example of the kinds of zombies one might summon up at hearing just “the probability of [evidence] being due to chance is [so very small you would not believe it]”, the first question that pops into my head is, “Even if it’s not due to chance, how do we know it’s not due to some cause other than ESP?” I see you address that in your post,
so you do give up a report that sources of error have been controlled for (all sources? how well would I have to get to know the study to be reasonably certain enough sources of error had been controlled for?…) I tend to be quite pessimistic about experimental error, which is sometimes a valuable trait, other times less so.
(Certainly, all my personal experience with labwork is that the pessimism is well warranted. If I did believe in telekinesis, I would believe that I, personally, radiated a very strong “error field” that causes mechanical items to bust more often simply through my proximity rather than, say, due to my clumsiness in handling them. On the other hand, years of living with a clumsiness-causing mutation without knowing I had it might be the better explanation.)
I’m reminded of a quote from the famous sceptic Richard Wiseman, who said:
The notion, as presented in the OP, that reasoning from such a patho-sceptical prior may still be rational does not clear away the original sin of starting from such a poor prior – one that, in fact, doesn’t stand up to much scrutiny given the “natural history” of the subject and the number of people who claim psychic experiences. It is somewhat pathological to assert that so many people are not just mistaken but deluded, when Pim Van Lommel has plausibly estimated that about 2 million people in Europe have had NDEs, based on heart attack rates and the number of heart attack patients who report NDEs.
Furthermore, arguing that there’s probably reporting error or subterfuge really doesn’t cut the mustard when so much psi research has been so thoroughly and carefully controlled and blinded, and can be shown to be free of the file-drawer effect – markedly more so than other areas of science, due to the great degree of criticism levelled against it. An example of the level of care taken in designing experiments in this field is Julie Beischel’s quintuply-blinded work on mediumship.
Also there are many examples of “sceptics” engaging in deception (e.g., Randi and Wiseman), and moving goalposts when a study shows a positive – the latter being something the OP seems to endorse. Sceptics rarely do experiments: they tend to sit back and theorize about possible ways an experiment could be wrong, or could have been “gamed”. If all else fails, they cry “Fraud!”. This is non-serious engagement with the field. This attitude can be rationalized, but whatever it is, it’s not science.
I’d recommend Dean Radin’s Entangled Minds (as mentioned and reviewed by anonymous) or Robert McLuhan’s Randi’s Prize for an intro to the subject. There’s also the Psi Encyclopedia. But the bottom line is that personal, repeated and veridical experience over a long period of time is really the only way to prove to oneself the reality of psi.
I am not so sure that we define ESP in the same way. Also, I am not certain that it is based on somal elements, such as DNA. (Yes, I know the premise of my books is exactly that psychic powers are DNA-based, but my books are fictional.) So, because an individual has ESP and it works would not necessarily be a desirable trait that would also be passed on to children.
Even if it were DNA-based, that does not mean that it would be a survival trait throughout human history. For instance, in the past, “witches” (often really people with herbal or unapproved spiritual knowledge or abilities) have been judicially murdered for their knowledge and abilities. This would tend to work against the spread of a weak DNA-based power throughout humanity. Any of those showing too much power in such societies would be culled.
Another factor is that those with ESP might be less likely to procreate, since they can read people better and figure out what creeps they are. ;^D
Somehow no one has ever collected on Randi’s offer.
https://en.m.wikipedia.org/wiki/One_Million_Dollar_Paranormal_Challenge
Someone, in all the time it was offered, would have been able to collect. They did not. Unexplained results on one test does not mean ESP.
When some is able to do something other than parlor tricks, I will be willing to belive. When there are objective results, not anecdotes, then yes. Human minds are lousy at figuring things out.
Randi’s prize is not science, and Randi himself is seriously compromised in all sorts of ways. The scandal-wracked JREF has now been shut down, by the way.