Friday, February 22, 2008

Sifting testimonial evidence

Many sceptics use the facile formula that extraordinary claims demand extraordinary evidence to discount miracles. Likewise, career sceptics (e.g. James Randi, Martin Gardner, Paul Kurtz) recycle the same stock objections to the paranormal that are leveled against Biblical miracles—or modern counterparts.

Stephen Braude is a philosopher who specializes in the study of the paranormal. In the course of his study, he evaluates testimonial evidence concerning the paranormal. Since objections to the paranormal generally parallel objections to the miracles of Scripture, his comments on testimonial evidence are quite germane to Christian apologetics. Just mentally substitute “the Resurrection,” “the raising of Lazarus,” “the plagues of Egypt,” or “the miraculous,” &c., for “the paranormal,” “psi,” &c., to see what I mean.

I’ll be quoting from two of his books. This will involve a certain amount of repetition with variation.

“It’s actually shameful to claim that the early investigators of mediums were more gullible than their successors…Moreover, the Argument from Gullibility suggests a shocking blindness to the current state of public gullibility. When you take into account, say, the widespread use of psychic hotlines and our fascination with sloppy and sensationalistic media coverage of psychic happenings, gullibility today arguably surpasses anything that preceded it. Besides, there’s no hard data on gullibility levels (much less a gullibility index) to which we can appeal here. But then the Argument from Gullibility seems merely to be a thinly veiled complaint that since mediumistic phenomena are impossible, people must have been more credulous in the old days,” S. Braude, The Gold Leaf Lady and Other Parapsychological Investigations (U of Chicago Press 2007), 27-28.

“Furthermore, it’s equally lame to appeal to advancing technology’s potential for fraud suppression. For one thing, the Argument from Technology is a double-edged sword. If nineteenth-century technology limited the means for detecting fraud, it also limited the means for producing it…Similarly, if current technology—for example, miniaturized, remote-controlled, and automated electronics—enhances our ability to detect various kinds of fraud, it also enhances our ability to produce it. After all, magicians can perform convincing tricks today that simply were not feasible before,” ibid. 28.

“Several factors influence whether or not (or to what degree) we accept a particular observation claim. Probably the most important are: (a) the capabilities, condition, interests, and integrity of the observer, (b) the nature of the object/s allegedly observed, and (c) the means of observation and the conditions under which the observation occurred. When we evaluate reports of paranormal phenomena, we weight these factors differently in different cases, But in general, it matters: (a) whether the observers are trained, sober, honest, alert, calm, prone to exaggeration, subject to flights of imagination, blessed with good eyesight, and whether they have strong prior interests in observing carefully and accurately; (b) whether the objects are too small to see easily, whether they’re easily mistaken for other things, or whether (like fairies, extraterrestrials, and unicorns) they’re of a kind whose existence can’t be taken for granted; and (c) whether the objects were observed at close range, with or without the aid of instruments, whether they were stationary or moving rapidly, whether the observation occurred under decent light, through a dirty window, amidst various distractions, etc.,” ibid. 33.

“Perhaps the most familiar skeptical argument in this context is that reports in question are examples of biased testimony. That is, witnesses of paranormal physical phenomena—mediumistic or otherwise—are predisposed to see either miraculous things generally, or certain paranormal phenomena in particular. But in that case (so the argument goes), they’re likely to be guilty either of motivated misperception or outright fabrication,” ibid. 33.

“Initially at least, this Argument from Human Bias might seem perfectly reasonable. After all, there’s no doubt that some people misperceive or lie, and there’s also no doubt that their predispositions might be one reason for these lapses. Nevertheless, this argument turns out on closer inspection to be remarkably flimsy, for several reasons,” ibid. 34.

“First, even if witnesses were biased to experience paranormal physical phenomena, that wouldn’t explain why independent reports agree on peculiar details…But to my knowledge, no proponent of the Argument from Human Bias has developed a psychological theory (much less a credible theory) explaining how people could be biased to make these specific reports,” ibid. 34.

“Second, an argument from bias could be used to undermine virtually every scientific report requiring instrument readings and ordinary human observation. After all, it’s not just parapsychologists and ‘plain folk’ who have strong beliefs, desires, and predispositions about how the universe works. Presumably, mainstream scientists have at least as much at stake and at least as many reasons for perceptual biases as do witnesses of the paranormal. They might even have more, considering how success in the lab can make or break their careers, especially when their research is novel and potentially groundbreaking,” ibid. 34.

“Third (and even m ore important), like the Argument from Technology, the Argument from Human Bias is doubled-edged. Obviously, biases cut two ways, against reports by the credulous and the incredulous. So if a bias in favor of psi phenomena might lead people to misperceive or to lie, so might biases against psi phenomena. And those negative biases are arguably at least as prevalent—and certainly sometimes as fanatical—as those in favor of the paranormal. Anyone who thinks otherwise simply hasn’t been paying attention. In fact, the history of parapsychology chronicles some remarkable examples of dishonest testimony and other reprehensible behavior on the part of skeptics…So, we adopt an indefensible double standard if we distrust only testimony in favor of the paranormal,” ibid. 34.

“Fourth, the only way to make the Argument from Human Bias with a straight face and a clear conscience is from a position of benign (rather than willful) ignorance regarding the data. It’s obvious that many who investigate the paranormal are motivated primarily by curiosity and the need to know (whatever the outcome). In fact, in some of the best cases, witnesses of mediumistic phenomena have clearly been biased against the reported phenomena,” ibid. 35.

“Fifth, although many observers may be open to the possibility of psychic phenomena, that’s not the same as being biased in their favor. For example, one can be open to the possibility of a phenomenon (say, alien visitations) while thinking that its actual occurrence is highly improbable. In fact, one can be open to the possibility of a phenomenon and also biased against observing it…That’s similar to the way parents can be blinded to drug use among their children. Even when they concede that it’s not literally impossible that their children use drugs, they might also feel strongly that it’s something that happens only in other families,” ibid. 35.

“Similar considerations apply to the skeptical argument that because memory is notoriously unreliable, witnesses are simply liable to forget or misremember…[But] much of the scientific evidence for memory loss concerns experiments with boring or very ordinary material (e.g. dull stories or nonsense syllables). For those with no faith in common sense (or those who think the government needs to finance large research grants to confirm what any sensible person already knew), evidence also confirms the commonsense observation that people tend to remember dramatic, interesting, and relevant events, and that those memories change or fade very little over time,” ibid. 36.

“The most radical argument would be a sweeping indictment of all human testimony. Some might argue that observation and testimony are inherently fallible, and that what is inherently fallible cannot be trusted. But of course the matter is not this simple. The possibility of error exists equally with respect to sources of evidence on which we rely all the time—for example, laboratory studies in science, which are based on various sorts of observation, notation, and instrument readings—all far from incorrigible,” S. Braude, The Limits of Influence (Routledge & Kregal Paul 1986), 26.

“Sceptics might concede that human testimony generally is suspect, but that some cases are better documented that others, especially scientific laboratory reports. After all, they might say, many scientists, on the same or different occasions, report the same results; and such collective and repeated testimony is more credible than the isolated and untestable reports founding the semi-experimental and anecdotal literature of parapsychology…But there exist numerous collective eyewitness accounts of phenomena, and reports of unusual sorts of phenomena occurring on more than one seems to me that such convergence of independent testimony cannot easily be brushed aside,” ibid. 26-27.

“Nevertheless, some might protest that witnesses of ostensibly paranormal phenomena are disposed to see the miraculous, or to see what they want, and thus are prone to misperceive or deceive themselves, and perhaps even lie or exaggerate (possibly unconsciously) in order to protect their preconceptions…But this rejoinder, which we may call ‘The Argument from Human Bias,’ is still unsatisfactory, and for two reasons,” ibid. 28.

“Even if witnesses of ostensibly paranormal phenomena were biased or predisposed to see such things, this would not explain why the biased misperceptions or reports should be similar in so many peculiar details,” ibid. 28.

“Moreover, it is not clearly to the skeptic’s advantage to rely heavily on the Argument from Human Bias. That argument cuts two ways, against reports by the credulous and the incredulous. If our biases may lead us to malobserve, or misremember, or lie, then we should be a suspicious of testimony from non-believers as from believers. If (on the basis of their favorable dispositions) we distrust reports by the apparently credulous or sympathetic that certain odd phenomena occurred, we should (by parity of reasoning) be equally wary of reports by the incredulous or unsympathetic that the alleged phenomena did not occur (or that cheating occurred instead),” ibid. 28-29.

“For example, Ducasse wrote…’there is likely to be just as much wishful thinking, prejudice, emotion, snap judgment, naiveté, and intellectual dishonesty on the side of…scepticism…as on the side of hunger for and of belief in the marvelous. The emotional motivation for irresponsible disbelief is, in fact, probably even stronger—especially in scientifically educated persons whose pride of knowledge is at stake—than it is in other persons the motivation for irresponsible belief,” ibid. 29.

“Ducasse’s caveat about irresponsible disbelief is buttressed by a wealth of evidence. For one thing, according to Stevenson (1968), p112), experiments have revealed a number of interesting ways in which peer pressure and other contextual factors can apparently influence a person’s perceptions or perception reports. But even apart from the experimental evidence, the history of parapsychology chronicles an astounding degree of blindness, intellectual cowardice, and mendacity on the part of skeptics and ardent non-believers, some of them prominent scientists,” ibid. 29-30.

“A person’s merely being open to he possibility of a phenomenon would not explain why the person should actually report having observed it…For example, many would concede that it is possible than alien spaceships will visit or have visited the Earth, while nevertheless assigning to such an event a probability approaching 0. As a matter of fact, one can be open to the possibility of P but be biased against observing or believing in P. This is undoubtedly why many parents fail to register clues indicating that their children have been smoking marijuana, even though they would admit that such an event is empirically possible,” ibid. 35-36.

“In fact, given the preparedness and occasional skepticism of the observers, as well as the large-scale nature of some reported phenomena, there is reason to think that witnesses might be less liable to malobserve than are witnesses of more ordinary events. One would need to posit a magnitude of error for these cases considerably greater than that generally required to undermine eyewitness accounts of ordinary events (e.g., crimes, domestic squabbles, or occurrences during military campaigns). Normal events are often observed and reported under conditions at least as conducive to error as those encountered by psychical researchers, and sometimes more so,” ibid. 39.

“In fact, eyewitness reports in parapsychology may be even less suspect than many scientific laboratory reports. The collecting of experimental data often requires great alertness, and is easily subverted by a momentary relaxation of attention. This, the soporifically routine and painstaking observations of some scientific studies may be more conducive to (minor but critical) error than the immediate and unusual experience of a large-scale paranormal event,” 39-40.

“Therefore, if malobservation is no more probable in the case of large-scale ostensibly paranormal phenomena than in the case of many normal phenomena, it would seem that reports of the former are no more inherently unreliable than reports of the latter. But then to reject eyewitness accounts of large-scale phenomena simply because the phenomena reported seem paranormal is to hold an indefensible double standard with respect to eyewitness testimony,” ibid. 40.

“Furthermore, skeptics have little to gain by appealing to the fallibility of memory…non-experimental cases frequently concern events that are far more easily remembered. They are often emotionally intense and highly interesting, and the subject (ether for these reasons or from an interest in the paranormal) is frequently highly motivated to remember what occurred…[as D. S. Gardner observed] ‘The extraordinary, colorful, novel, unusual, and interesting scenes attract our attention and hold our interest, both attention and interest being important aids to memory. The opposite of this principle is inversely true—routine, commonplace and insignificant circumstances are rarely remembered as specific incidents’,” ibid. 40.

“For that matter, we now know that observers of ostensibly paranormal phenomena have sometimes withheld information, for fear of ridicule or loss of professional prestige and credibility…Thus, Richet admitted, in his disarmingly candid address to the S.P.R., ‘In the course of these studies [in somnambulism] I had here and there observed certain facts of lucidity, of premonition, of telepathy; but since these facts were denied and ridiculed on every side, I had not pushed independence of mind so far as to believe them. I deliberately shut my eyes to phenomena which lay plain before me, and rather than discuss them I chose the easier course of denying them altogether. Or, I should rather say, instead of pondering on these inexplicable facts I simply put them aside, and set them down to some illusion, or some error of observation’,” ibid. 42.

“Now I confess that I find a retreat to this position [collective hallucination] rather desperate. Its flaws, however, are instructive. To begin with, as far as I can ascertain, there simply is no evidence—apart from the ostensibly paranormal cases, apparent UFO sightings, and some biblical stories where the hypotheses of collective hallucination and hypnosis are advanced as explanations—that such collective, concordant, non-paranormal, and non-veridical experiences ever occur. We know, of course, that people are susceptible to hypnotic suggestion and hallucination. But if we have no evidence, apart from the peculiar cases in question, that the proposed sort of collective hallucination or hypnosis, occurs, then these counter-hypotheses are extremely weak indeed,” ibid. 43.

“For those still intent on challenging the authenticity of the case reports and eyewitness accounts, the only remaining option, as far as I can see, would be to maintain that the testimony results from some combination of those factors already discussed…this would clearly be a last-ditch attempt to discredit the non-experimental evidence, and I propose that we call it, somewhat disdainfully, hodge-podge skepticism,” ibid. 51.

“But as Broad (1962a) observed, this position is plausible, at best, only when we consider the cases one at a time. Even when a skeptical hypothesis works on a case-by-case basis, this does not thereby support a general skepticism with regard to the total corpus of cases,” ibid. 51.

“Broad writes, ‘Provided that one is prepared to stretch the arm of coincidence far enough, to postulate sufficient imbecility and dishonesty on the parts of investigators who are known to be in other respects intelligent and truthful, to suppose that the narrators have gone to considerable trouble in falsifying diaries and forging letters with no obvious motive, it is always possible to suggest a normal, or at worst an abnormal, explanation for any story of an ostensibly paranormal sporadic event,” ibid. 51.

“Precisely because the phenomena are not ordinary, and so long as they remain not well understood, we lack the kind of information customarily needed to assess the probability of such events having occurred. To judge whether a given event is likely in a particular circumstance, we must first know something of the event’s nature and limits…But it is just this sort of information that we lack in the case of ostensibly paranormal events,” ibid. 53.

“To this we could add Ducasse’s observation that ‘assertions of antecedent improbability always rest on the tacit but often in fact false assumption that the operative factors are the same in a presented case as they were in superficially similar past cases. For example, the antecedent improbability of the things an expert conjurer does on stage is extremely high if one takes as antecedent evidence what merely an ordinary person, under ordinary instead of staged conditions can do. The same is true of what geniuses, or so-called arithmetical prodigies, can do as compared with what ordinary men can do’,” ibid. 54.

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