Tec: In reference to evidence - “It might not be enough for some people”
I hear this argument from time to time. It’s basically saying the fault lies with the other party for not agreeing with the evidence already presented. I would counter that the evidence hasn’t met necessary criteria for evidential reasoning. The FiLCHeRS are as follows:
Falsifiability -- It must be possible to conceive of evidence that would prove the claim
false. If nothing conceivable could ever disprove a claim, it is meaningless. There are two
principle ways this rule is violated:
-- By the undeclared claim: a statement so broad or vague that it lacks propositional
content, such as the claim that quartz crystals can restore balance and harmony to a
person's spiritual energy. How could you disprove that? The undeclared claim has the
advantage that virtually any evidence that could be adduced may be interpreted as
confirming the claim. It is especially popular with paranormalists.
-- By the multiple out, which is an inexhaustible series of excuses intended to explain
away evidence that would seem to falsify the claim. Psychic healers, for example, will
attribute failure to a person's lack of faith. The multiple out means, in effect, "Heads I
win, tails you lose."
Logic -- Any argument in support of a claim must be both valid and sound. To be valid,
the arguments premises must be true. To be sound, the rules of logic must be correctly
used to reach conclusions based on such premises.
Comprehensiveness -- The evidence must be exhaustive--that is, all of the available
evidence must be considered. The successes of psychics, for example, are cited without
reference to their much more numerous failures.
Honesty -- The evidence must be evaluated without self-deception. Parapsychologists
violate this rule when they conclude, after failure to replicate an initially positive result,
that psi must be an elusive phenonemon. The more honest conclusion would be that the
original result must have been a coincidence.
Replicability -- If the evidence for a claim is based upon an experimental result, or if the
evidence offered in support of a claim could logically be explained as coincidental, then
the result must be repeated in subsequent experiments or trials.
The rule of replicability, which requires independent persons to follow the same
procedures and achieve the same results, is an effective way of correcting bias, error, or
fraud in experiments. When I correctly predict the roll of the dice, is it psychic ability or
coincidence? You should demand that I repeat feat a convincing number of times.
Sufficiency -- The evidence offered in support of a claim must be adquate to establish the
truth of that claim:
-- The burden of proof for any claim rests on the claimant. UFO buffs argue that UFO
sightings not explained by skeptics must be extraterrestrial spacecraft. Hitler is alive and
well in Argentina. Is it true just because you can't prove me wrong?
-- Extraordinary claims demand extraordinary evidence. If I claim that it rained on my
way to work last Tuesday, you would be justified in assigning that claim considerable
credibility. But if I claim that I was abducted by Martians, you would want better
evidence.
-- Evidence based on authority and/or testimony is inadquate for any extraordinary
claim. No amount of expertise in a field is a guarantee against human fallibility, nor does
expertise preclude the motivation to lie.
Passing all six tests does not assure that a claim is true (there may be contrary evidence
tomorrow), but it does mean that you have sold your conviction for a fair price, and that
it has not been filched from you.
The above cut and paste has been brought to you by James Lett in the Winter 1990 issue of
Skeptical Enquirer