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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
That is not what I said, Bryan. I said that if one believes that humans are more than physical, it opens up other possibilities for transmission or development that do not involve transmission through DNA.
If you considered saying I should be embarrassed and exchange of viewpoints, I guess so. I consider it rude. You have insulted me because I don’t belive as you do.
You have a claim that does not fit with the world as we know it. That requires significant proof. Yet, you can’t provide it.
So, insult away.
Prove it. Shoe me how it works.
Maybe not…. I don’t understand epigenetics very well. But some things are transmitted, not through DNA, but through the DNA’s immediate environment. There are heritable changes in DNA function that don’t correspond to changes in the DNA sequence itself.
Well this is of course a very thorny subject, because we don’t understand the human mind, but we do know that biological organisms have not evolved to perceive objective reality (that experiment with Australian beetles shagging beer bottles is a good example), and as such there are mechanisms in the brain which can seem to play tricks with us, or which at the very least can lead us to false conclusions about the world.
However I think the public at large is extremely sceptical, and has always been so, when it comes to psi. There was a lot of scepticism even during the witch-trials hysteria, for instance. On a deep level we don’t want to be tricked. But when one regularly perceives things that one can’t possibly know about, in great detail, before they happen, that’s kinda weird. And I think that sceptics often don’t give credit to the scepticism of “believers”, or their ability to discriminate between tricks of the mind and genuine events. But that’s just my impression.
Please do! That would be an interesting addition to the conversation.
I have another addition to make (presenting one skeptic’s extremely pessimistic take) that I will post soon.
I don’t disagree with any of that. But rational ignorance doesn’t account for the energy that sceptics put into jumping on anyone who claims a belief in psi, and in justifying their own disbelief of psi. (OK, not all sceptics do that, but there are a sizeable minority who do.)
John, if people can change a clock swing, they can change a clock swing. Teke is Teke.
I am not unreasonable in wanting simple proof. Your link on retrocausality does not even make a claim.
Absolutely not. I am already under enough fire now. I answered what I thought would be proof as you asked in the OP, and a mod ridiculed me for it.
Have someone stop s clock with their mind. Have someone read the sentence from my mind.
If this psi is so easy to prove, John, why hasn’t it been.
And the superconductors work.
Prove which? That there is a non-physical component called the soul? Or prove that one can posit non-DNA generated means for psychic phenomena if one allows for a non-physical component?
If you do not believe a human is more than a bag of chemicals, in other words you are looking for proof of the former, I have already suggested that it is not worth discussing it further. If you don’t believe in a soul, why should I work hard enough to get you that far, just so I can posit that psi phenomena are non-somal? I’m perfectly willing to let you keep your beliefs.
On the other hand, if you are at least open to the possibility of a (non-physical) soul, I can posit at least two forms of non-DNA “transmission” of psychic phenomena. So, which is it?
Prove there is a non genetic or epigenetic transmission of traits.
It’s still a form of physical transmission. And once again, my comment was about theories that do not involve physical transmission. Why is this so difficult to understand?
Actually this phenomenon is reported quite frequently in nursing homes, hospices and private homes upon death. Peter Fenwick touches upon this, but the “natural history” is long and goes back to Phantasms of the Living. Yet I feel sure you’ll insist this be proven under “laboratory conditions”, which generally means conditions under which the phenomenon is inhibited. One of the really tough issues in psi research is what constitutes proper laboratory conditions. To make an analogy, it’s impossible to get superconductivity as yet at room temperature, but nobody would insist that it cannot happen unless proven under those conditions.
That is anecdotal and not at all what I meant.
Float a penny. Float a pencil. Read my mind of a 10 digit number.
I have said my level of evidence as asked. Guess you all don’t like that answer.
I edited my comment before you replied, to bring in questions of what constitutes good evidence.
However in response to what you’ve said here, I don’t think it’s reasonable to arbitrarily set standards of evidence such as to “float a penny”. The effect size of psi experiments is generally quite small. I think you ought to consider that. In general I feel you are not serious in making such demands. After all, why not just demand I levitate the Eiffel Tower? You’re presuming a lot.
I do consider that. It is why it does not make me belive. And ever derision of that, has used counter examples with big effects.
So, I answered th OP. You don’t like it, and have insulted me for it. Peace.
Specialists in psychology are particularly attuned to the possibility that a seemingly-ordinary brain may be deeply weird. Perhaps this leads some psychologists to believe more in ESP (ESP would be deeply weird).
On the other hand, contemplating the wealth of ways human brains can be weird without having to rely on ESP as an explanation could lead psychologists to find alternate explanations for paranormal-seeming phenomena much more likely, hence making them more skeptical of ESP.
My personal experience as an intuitive and extremely forgetful person (or rather, one whose recall is amazingly poor given general intelligence level) is that I’m often left with the impression I don’t have the knowledge necessary to know something I know.
I realize that says nothing about other people, who may be confident enough in their memories and perceptions to declare, “I couldn’t possibly have known about this through non-paranormal/non-supernatural means.” It may mean I am personally lacking the confidence necessary to distinguish between “I can’t recall how I know that” and “The reason I can’t recall how I know that is because I couldn’t possibly know it.”
I am willing to regard my mind as pretty abnormal. But if I believed my mind were fairly normal in this respect, I might think it’s normal for people to have the impression they don’t have the knowledge necessary to know something they know even when, if only they could recall it, they do.
That’s not what I said I could do, Bryan. I said that such could be posited. I doubt I could prove to you that I exist, even by punching you in the nose. I’m pretty skeptical about your independent existence, too, for that matter.
But here are at least three ways, both tied to the soul:
Charming.
Well, when I was talking about perceiving things in detail before they’ve happened, I was referring to events that really couldn’t be predicted. Not necessarily specific details of plane crashes, etc., but you get the idea of the kind of thing I mean. Stuff that nobody could know, not merely things that could be worked out on a subconscious level.
I do understand your appeal to some form of transmission other than physical. I am just observing that believing in a nonmaterialistic component to the universe doesn’t seem to distinguish people who believe in ESP from those who don’t.
For example, there are traditional Christians who believe in a spiritual realm who nonetheless doubt the existence of psi, and materialists who believe psi is a measurable phenomenon.
You would also have to be very confident that what you remember premembering (to coin a word for precognition) is something you really did premember at the time you remember premembering it.
Memory, even memory based on external evidence, like a written note to your future self, is a reconstructive process. As if you’re imagining the most likely past.
Last Enemy is a great science fiction story. It is set in a parallel universe where the people have proof of reincarnation. Because there is scientific proof, reincarnation has been incorporated into their politics. But their knowledge is not yet enough at the beginning of the story to determine the means of reincarnation, and as such, there are two major parties. The Statisticalists believe that the soul is somnambulant and goes to the closest available baby and reincarnates. This leads to their wanting to create a society of equal outcomes. The Volitionists believe the soul is conscious between incarnations and can choose reincarnation vehicles. The story is about the political effects engendered by new scientific proof supporting the Volitionists.
As this proof comes out, though, the Statisticalists spend their time trying to prove that the new evidence and proof was faked. They stop at no means to discredit the evidence that does not conform to their world view.
It’s a very good story.
Did you ever see the SNL sketch with Christopher Walking spoofing himself from the Dead Zone? In the sketch, all he could see was useless trivia. Things like, “You will… have dinner at McDonalds” kind of stuff. It’s too bad that SNL sketches are so heavily policed on Youtube, I’d love to find a link to that sketch again. What I’ve experienced has been kinda like that, only more muddled – bits of stark clarity while dreaming or only half awake, difficult to sort from the dream chaff and recognizable as having been visions only when later experienced. Save for 1 time.
Like Arahant alluded to above, it felt like finding a disused and atrophied muscle and making it briefly work.
True.
After a few G&Ts I can assure you I am pretty damn confident of that… erm… whatever that is ;-)
But seriously, some things (let’s say a tsunami) are not known in advance.
Dream and vision logs help that. Mine is a time-stamped database.
Whenever I see or hear the phrase spooky action at a distance I reach for my revolver. There’s nothing spooky about quantum entanglement. It’s been part of standard quantum mechanics for well over half a century. Just because something is hard to understand or counter-intuitive, that doesn’t make it spooky or somehow related to the paranormal. Our intuitions are weak when it comes to phenomena outside of everyday experience. The behavior of individual or small numbers of elementary particles is well outside of first-hand human experience.