A Commentary by Marcello Truzzi
Over the years, I have decried the misuse of the term "skeptic" when used to refer to all critics of anomaly claims. Alas, the label has been thus misapplied by both proponents and critics of the paranormal. Sometimes users of the term have distinguished between so-called "soft" versus "hard" skeptics, and I in part revived the term "zetetic" because of the term's misuse. But I now think the problems created go beyond mere terminology and matters need to be set right.
Since "skepticism" properly refers to doubt rather than denial--nonbelief rather than belief--critics who take the negative rather than an agnostic position but still call themselves "skeptics" are actually pseudo-skeptics and have, I believed, gained a false advantage by usurping that label.
In science, the burden of proof falls upon the claimant; and the more extraordinary a claim, the heavier is the burden of proof demanded. The true skeptic takes an agnostic position, one that says the claim is not proved rather than disproved. He asserts that the claimant has not borne the burden of proof and that science must continue to build its cognitive map of reality without incorporating the extraordinary claim as a new "fact."
Since the true skeptic does not assert a claim, he has no burden to prove anything. He just goes on using the established theories of "conventional science" as usual. But if a critic asserts that there is evidence for disproof, that he has a negative hypothesis --saying, for instance, that a seeming psi result was actually due to an artifact--he is making a claim and therefore also has to bear a burden of proof.
Sometimes, such negative claims by critics are also quite extraordinary--for example, that a UFO was actually a giant plasma, or that someone in a psi experiment was cued via an abnormal ability to hear a high pitch others with normal ears would fail to notice. In such cases the negative claimant also may have to bear a heavier burden of proof than might normally be expected.
Critics who assert negative claims, but who mistakenly call themselves "skeptics," often act as though they have no burden of proof placed on them at all, though such a stance would be appropriate only for the agnostic or true skeptic. A result of this is that many critics seem to feel it is only necessary to present a case for their counter-claims based upon plausibility rather than empirical evidence.
Thus, if a subject in a psi experiment can be shown to have had an opportunity to cheat, many critics seem to assume not merely that he probably did cheat, but that he must have, regardless of what may be the complete absence of evidence that he did so cheat and sometimes even ignoring evidence of the subject's past reputation for honesty. Similarly, improper randomization procedures are sometimes assumed to be the cause of a subject's high psi scores even though all that has been established is the possibility of such an artifact having been the real cause.
Of course, the evidential weight of the experiment is greatly reduced when we discover an opening in the design that would allow an artifact to confound the results. Discovering an opportunity for error should make such experiments less evidential and usually unconvincing. It usually disproves the claim that the experiment was "air tight" against error, but it does not disprove the anomaly claim.
Showing evidence is unconvincing is not grounds for completely dismissing it. If a critic asserts that the result was due to artifact X, that critic then has the burden of proof to demonstrate that artifact X can and probably did produce such results under such circumstances. Admittedly, in some cases the appeal to mere plausibility that an artifact produced the result may be so great that nearly all would accept the argument; for example, when we learn that someone known to have cheated in the past had an opportunity to cheat in this instance, we might reasonably conclude he probably cheated this time, too.
But in far too many instances, the critic who makes a merely plausible argument for an artifact closes the door on future research when proper science demands that his hypothesis of an artifact should also be tested. Alas, most critics seem happy to sit in their armchairs producing post hoc counter-explanations. Whichever side ends up with the true story, science best progresses through laboratory investigations.
On the other hand, proponents of an anomaly claim who recognize the above fallacy may go too far in the other direction. Some argue, like Lombroso when he defended the mediumship of Palladino, that the presence of wigs does not deny the existence of real hair. All of us must remember science can tell us what is empirically unlikely but not what is empirically impossible.
Evidence in science is always a matter of degree and is seldom if ever absolutely conclusive.
Some proponents of anomaly claims, like some critics, seen unwilling to consider evidence in probabilistic terms, clinging to any slim loose end as though the critic must disprove all evidence ever put forward for a particular claim. Both critics and proponents need to learn to think of adjudication in science as more like that found in the law courts, imperfect and with varying degrees of proof and evidence. Absolute truth, like absolute justice, is seldom obtainable. We can only do our best to approximate them.