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ESP and the Other Guy’s Zombie Army
How much evidence would it take to get you to believe in ESP? Most of us who are skeptical would say it would take a lot of evidence to convince us – that the reason we’re unconvinced is that we haven’t seen such evidence. And yet, were we presented with such evidence, chances are good that we’d still disbelieve it. That’s irrational, right?
Well, not necessarily.
Our lived experience supplies us with initial impressions of how plausible various claims might be, plausibilities that can be estimated as prior probabilities. If we suppose our brains reason correctly in a Bayesian way, then finding a claim extremely implausible amounts to assigning it a very low prior probability. Not exactly zero, since assigning a prior probability of exactly zero is equivalent to asserting no amount of evidence, however good, could change the reasoner’s mind, and that’s not what implausible (as opposed to impossible) means. But close enough to zero to be treated as such for most purposes – except, of course, one would hope, when we’re asked to re-evaluate evidence of the claim itself.
Classical statistics makes fruitful use of cleverly dividing hypotheses up into the null hypothesis and one alternative hypothesis. However, the human imagination is capable of entertaining multiple alternative hypotheses at once, with an intuitive sense, based on experience, of how plausible each is even before new data is presented to it. Nor, Bayesians claim, is the human imagination irrational for doing so. Indeed, the faculty of drawing prior probabilities from experience and correctly updating them in light of new evidence is the essence of Bayesian rationality.
Different experiences lead to differing prior estimates, and because of this, it should not be surprising that different people require differing amounts of evidence to be convinced of a claim. When a claim is supported by evidence that already comports with our experience, we are naturally – and rationally – more inclined to lend it credence based on that evidence. When a claim seems extraordinary to us in some way, we trot out the line “extraordinary claims require extraordinary evidence,” and demand more. The seeming paradox – and evidence of our gross irrationality to the one trying to convince us – is that we may persist in our disbelief even in the face of that extraordinary evidence. Life teaches us the sad lesson that different people’s beliefs do not necessarily converge when presented with the same evidence, but may in fact diverge further! Irrational! Identity-protective cognition! Motivated reasoning! Human perversity!
Well, not so fast. As physicist and Bayesian scholar ET Jaynes points out, it is possible for this divergence to be entirely consistent with correct Bayesian reasoning on differing priors. As he notes, when we’re presented with evidence, we’re usually not experiencing the evidence directly, but hearing a report of it, and one hypothesis likely lurking in the back of our minds somewhere is that the evidence presented to us contains reporting errors. Has the evidence reported been filtered through some other guy’s cognitive biases, or perhaps through publication bias or some other form (however unintentional) of cherry-picking? Might we suspect that the extraordinary evidence is only extraordinary because of experimental error? Might we even sometimes suspect deliberate deception?
Not only may we, but the more extraordinarily the evidence that supports an extraordinary claim seems, the more we might suspect chicanery. These are our alternative hypotheses for explaining the data presented to us, and even where trust is high, and we’re willing to believe reporting error is unlikely, if the extraordinary claim we’re asked to believe on this evidence strikes us as even more unlikely than reporting error, all the evidence does is convince us of reporting error rather than the claim!
Jaynes calls such reporting errors “deception,” on the grounds that it does not matter whether the deception is completely inadvertent. But for many of us, deception implies intent, so I prefer calling it “reporting error” instead. In “Queer uses for probability theory”, perhaps one of the most entertaining chapters ever of an applied math book (the mathematically curious can follow along starting p 149 of this PDF), he discusses the famous Soal experiment in ESP and why “this kind of experiment can never convince [Jaynes] of the reality” 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 than [the hypothesis of telepathic powers], 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 [reporting error] 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 [reporting error] in the mind of the reader. As (5.15) shows, the reader’s total prior probability for deception by all mechanisms must be pushed down below that of ESP.
In claiming extraordinary evidence to support an extraordinary hypothesis, the claimant may inadvertently resurrect “dead hypotheses” members of his audience already regard as so implausible as to have likelihoods near zero – but still not, in their minds, as close to zero as the extraordinary hypothesis his evidence is claimed to support. You might call these zombie hypotheses, for their propensity to spring back to life in seemingly endless numbers and feast on people’s brains.
As Jaynes notes, an attack of zombie hypotheses can happen even in high-trust environments, and even when the extraordinary claim is true and the evidence supporting it is valid. Indeed, such things have happened to him in his work as a physicist. Such zombie attacks, he notes, 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 such zombie attacks can occur even in high-trust environments among people (like scientists) who share a great deal of common background experience, how much more likely are they to occur in politics, where trust is lower and people routinely suspect “deception” not only in the form of innocent reporting error, but also in the sense of intentional, deliberate deception?
It is no accident that political debate so often devolves into resurrecting the other guy’s zombie hypotheses, then concluding from the sheer number of zombies that seem to exist in his mind, that he must be crazy, flagrantly and deliberately rationalizing, or both, for continuing to attack our own truthful reasoning with so many mythical creatures. That he may also be reasoning correctly, given his experience, and his zombie army might be evidence of this, is almost too horrible to think about.
“You and what army?” we’re often tempted to think of an opponent. His zombie army – the army of all the hypotheses our opponent may quite reasonably, based on his prior experience, find more plausible, according to the evidence we present him, than our claim — that’s who. For evidence cannot be interpreted except in light of prior beliefs. And because two people’s prior beliefs can 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.
So unfortunately for us, even when everyone involved is reasoning perfectly, data never absolutely supports or refutes any claim, but only supports or refutes it relative to all the other (“prior”) information we have. When experience leads us to sufficiently differing prior beliefs, the same data that supports a claim for one of us may refute it for another – maddeningly, without either of us being in logical error!
We see that divergence 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 aren’t always disappointed) that the more data we share with one another, the more our beliefs will converge, it’s also logically possible for holding ever more data in common to drive two people’s opinions ever farther apart without either being in logical error. Now, logically possible isn’t the same as likely, and many of us, I’d guess, would find this possibility rather implausible. There is something too morally lazy – or simply too horrifying – about believing this logical possibility actually happens often enough to account for any significant portion of the disagreement in the world.
I know we have reasonable people on Ricochet on both sides of the ESP debate. I would be surprised if we had many on the side of “zombie hypotheses are often a good explanation for political disagreement” debate. Most of us, I think, have higher hopes for democracy than that, and would like to believe that “open discussion of public issues would tend to bring about a general consensus on them” whenever people are willing to be reasonable (thus preserving the inference that if consensus is absent, it’s because someone somewhere is being unreasonable). But – and perhaps it’s just because Halloween just past – I’ve been seeing a lot of zombies lately. What about you?
Published in General
The funny thing is that those who don’t believe are as likely to have the events happen as those who do. They just find ways to rationalize them away. My grandmother was one of those. But then she would go and do things with knowledge she couldn’t have had.
“That’s all a lot of nonsense.”
Well if we’re actually going to discuss ESP…
I find myself in the same place as Chesterton. I believe in a God who is more than capable of granting special revelations -including informing people that loved ones have died, inspiring them with knowledge they wouldn’t otherwise have, and otherwise a lot of ESP-like things I believe are perfectly consistent with divine behavior. But I am not going to go from there to a general belief in ESP. In the same way I believe in demons and even demonic possession, but it does not follow from this that it is common, or that any particular case is a possession rather than just a mental illness.
I don’t know that I could put this in formal Bayesian logic if you held a gun to my head, but I suppose the formal logic rule I’d rely on is that “True in part does not imply true in all.” Or the opposite of the fallacy of composition.
Now, wait one minute, sister. This has nothing to do with her STEM stuff. It has everything to do with base-level beliefs. There’s nothing wrong with STEM.
This actually seems to me a whole separate issue, and the real rub here. I feel like ESP as a self-contained phenomenon, a sixth sense of sorts, is a reaction to science’s (somehwat necessary) glorification of the mysteries of the brain. ESPers are essentially saying, “The brain’s not just intuitive within normal bounds; this is a diferrent kind of thing.”
But for religious people like me, to limit the supernatural insight, miracles, strange serendipities, near-death experiences, etc. to a particular psychic phenomenon comes off as rather limited. If we are not answering to the constant efforts of science to put more and more weight on the inexplicable activity of the brain (as I wrote about recently) we are free to view all sorts of supernatural phenomena as merely an extension of our first princples — as God creates nature, so he creates the unsystemized and inexplicable.
Right, but all of these types of occurrences can be classified under different names. That isn’t to say they aren’t closely related. It is just like at the base level of a cat and a tree, there is DNA. The cat and the tree grow from the same rule set, but we call them different things. We could call them both “live things.” But, of course, we categorize down to minute levels. So, when the title of the post mentions ESP, I know what ESP is, the particular set of phenomena in that grouping. That does not preclude the other phenomena; it just was not what Midge used in her example.
Well, except we know of “impossible” things brains do, at least compared to other brains, that are never thought of as supernatural, yet nonetheless remain “inexplicable”.
Some folks have “perfect” (or more accurately, absolute) pitch. Ask them to hum a middle C, and they hit the same frequency each time. Ask them to name any note, or the key of any piece, and they can – they “just know”. Others do not. Moreover, adults who attempt to learn perfect pitch apparently never get the results of those who “just have it” (though it’s possible the skill can be deliberately learned in childhood, at least by some). Perfect pitch seems to be a perfectly mundane way in which a few rare brains (1 in 10,000) subconsciously specialize while most brains do not. Moreover, those musicians I know with perfect pitch (and that I know several suggests perfect pitch is advantageous for musicianship, though definitely not necessary for it) often claim they cannot imagine what music would be like without it.
I once had a migraine that gave me a ringing in the ears at Eb6. A jingly ringing, like a telephone bell. It stayed like that for days. During that time, using good relative pitch, I could fake perfect pitch. But I’m sure migraines with extremely irritating auditory hallucinations are not how most people with perfect pitch achieve perfect pitch. There’s no meaningful explanation for that particular auditory hallucination, either.
Composing music can be its own auditory hallucination, only much more sophisticated (and less annoying) – “like taking dictation from God”.
Pain perception is also mysterious and complicated. Still quite inexplicable in several respects.
Our brains are weird. They do seem to do sophisticated (and occasionally perverse) things without us realizing it. I’m less certain these bizarre things our brains do without us realizing it are so very rare. They seem a normal part of life to me.
Probably shouldn’t go down this road, but what is the connection between a brain and a mind? I’m fairly sure that although we’re learning a lot about the brain and it’s chemistry, we don’t really know what the connection between mind and the brain is. Then what if the brain is less like a machine, and more like a receiver, like an old AM radio, full of skips and static?
I think it’s possible to remain fairly agnostic on the complete characterization of the relationship while also acknowledging that there is a relationship.
What we experience as senses – pain for example – is unlikely to be mere incoming signal received by the brain, but a learned state of awareness emerging from parts of the brain we may not even be aware of. Jaynes observes (also in the “Queer Uses” chapter) that optical illusions suggest that plain, ordinary sight is “not a direct apprehension of reality” but “inference from incomplete information”:
If merely experiencing a sense as a sense takes so much brainwork, none of which a healthy person should be the least bit aware of (think of how distracting such awareness would be!), then that the self-aware parts of the brain may be in continual communication with levels of the brain that never speak for themselves, but just pop stuff up into the conscious, seems plausible. Whether the mind is “merely” a property of the brain itself or something intimately received by the brain (or whether there’s often a meaningful distinction), we expect the “shape” of the mind to have something to do with the “shape” of the brain.
Brain chemistry is not as well understood as it’s sometimes made to sound. Here is one doctor’s youthful take on that – and him noodling on it being “Bayes all the way up”.
Where free will fits in to all this… for most of us, that we experience our wills as free (or at least lead more fulfilling lives when we perceive our wills as free) is enough. Bayesianism happens to be good for decision-making machines, so that we do decide (even if under sometimes agonizing constraints) is maybe not so physically weird. None of this renders moral reasoning or the wisdom of the ages obsolete, though it might mean the relation between moral state and physical state is not quite how we might picture it.
Regarding brain chemistry – Bryan Caplan rather (in?)famously tried to characterize mental illness as a weird preference rather than a budget constraint (as if “budget constraint” were an absolute category, rather than a constraint chosen – perhaps preferred – to set up a particular problem!). The same young doctor – a psychiatrist, not surprisingly – wrote a retort here, asking why should the same altered behavior (sickness behavior, in this case) be counted as “budgetary” or “preference-based” depending on the cause?
My own sense, from reading Caplan’s paper, is that Caplan is just not very familiar with the panoply of clearly physical ailments that obviously impose no hard budget constraints on human behavior, but just make certain behaviors so costly (in discomfort, fatigue, etc) that altered preference is a reasonable way to cope. (Caplan, for example, rather ridiculously claimed that not-sneezing is simply an unattainable good when one has a cold, overlooking the fact that, though sneezes are difficult to control, they can be controlled, albeit imperfectly, even when one has a cold, as performers and conscientious audience members know.)
There are better and worse ways to push back against the therapeutic tendencies of modern culture in order to preserve the time-honored sense of man as responsible for his own moral decisions. Though Caplan is quite a clever guy, I personally think he hit on a relatively worse way here.
In an nutshell you described Dualism, an ancient philosophy that still dominates discussions today. I would make entrenched arguments for both, but I have been procrastinating work enough. Do a search on Dualism Psychology and be ready to have your guard up for some serious quackery (I don’t subscribe to Dualism).
The classical null vs single hypothesis is a feature of a pair-wise evaluation, not a statement on the ultimate nature of the phenomenon.
The problem is that nothing you’ve said is more than “brains do inexplicable things.” This is not good enough to show that all phenomena are natural; it is not even good enough to show that all of these phenomena come from the brain. For the same price I could say, “souls do inexplicable things.”
A second point: There are significant differences between an outstanding talent, a hallucination, and a miracle. Many scientists, even as they emphasize the unexplained ability of brains to do nearly anything, have trouble with the idea that they can grasp normative logical categories, forms, essences. The differences between “X is a genius with intuitive insight into things,” “X is mad and lives in his own reality,” and “X is a prophet” were differences in antiquity as well. Moderns think that we are the first to insightfully point out that these things can appear similar; we are mistaken.
There are massive philosophical hurdles to the mind being reducible to the brain that in my opinion science will never clear.
Yeah. This.
Very true.
Perhaps it’s fortunate then, that I haven’t been insisting that all inexplicable phenomena be natural?
I do observe that very many inexplicable phenomena eventually turn out to have reasonable (at least to me) natural explanations. And I did assert that embodied souls do embody mental activity in their brains, and that brains are weird, though neither of those assertions identify the mind with the brain (although they don’t foreclose the possibility of such identification).
Neither my own observations about inexplicable phenomena nor the view that the brain seems to embody our minds in our bodies is proof or was meant as proof of the hardcore material reductionism I think you might think I’m engaging in. I believe the “worst” that can be said is I’ve been deliberately withholding judgment on the merits of such reductionism to focus on observations about thought and brain activity valid to both non-materialists and materialists, since we have both around here.
Well, sure, it’s true that those of antiquity noticed these things can appear similar, and moderns are not unique in this respect.
Nor has anything I said suggested that prophets’ insight into God is a delusion. It does seem, though, that the floridity or “spookiness” of prophets’ visions is not what distinguishes true from false prophecy. Describing true prophecy as “paranormal”, or “more paranormal” than false prophecy has no meaning to me.
It is enough to know that true prophecy is from God, the ultimate cause, whether or not we can also describe proximate natural causes for specific prophetic events, and that, when the faithful consult the prophets in the Bible, we typically seek prophets’ unique form of moral insight, not literalistic predictions effectively as mundane as “the only weather forecast 100% guaranteed by God!”
Aye. I firmly expect he’ll some day come out the other side of his opaque profundity into pellucid profundity.
On the contrary, this is (and always was) the method for distinguishing true prophet from false, because it’s undeniable.
Sorry for assuming you were going for materialist reductionism.