From: sichase@csa2.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.skeptic
Subject: Re: Why Psychics don't win
Date: 16 Apr 92 20:38:26 GMT
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
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In article <1992Apr14.215551.21876@donner.SanDiego.NCR.COM>, kraus@.SanDiego.NCR.COM (Dave Kraus) writes...

>Specifically, I feel that in the case of psi, many skeptics assume that
>studies like PEAR are invalid before they have been debunked, and are not
>basing their judgements on a true assessment of the evidence.

What else are we to do?  After enough inconclusive or debunked nonsense, you
draw a conclusion.  Am I forever obligated to study every paper on cold fusion
until the fanatics involved all drop dead?  Just because someone does an
experiment with "positive" results does not mean I have to believe it, or even
waste my time on it.

Maybe people don't realize how things science works in practice.  There are 
many experimental results which contradict one another but never get explained
one way or the other.  Try as you might, sometimes you can never figure out
what went wrong.  Then what?  Do we all just go home and cry?  No!  You
do new experiments and hope that a consensus of results will eventually 
weigh in one way or the other to settle the dispute.  

A nice example is the search for Magnetic Monopoles.  Blas Cabrera (at
Stanford - spelling might be wrong) announced the discovery of a single monopole
in 1981 (or 82).  Experts came from around the world to study his apparatus and
try to "debunk" it.  They tried to bang it, shock it, and generally annoy it,
in the hope of having it produce a signal identical to the one Cabrera had
found and claimed as evidence for monopoles.  Nobody could do it.  It was a 
perfect event.  Nevertheless, people were not entirely credulous, and better
experiments a decade later, one by Cabrera himself, have failed to find 
new monopole events, even with 10-100 times the sensitivity of the original 
detector.  

(To make sure that the new detectors were protected against all possible
electronic quirks, they all use coincidence measurements - essentially two 
detectors in proximity both of which should respond if a monopole flies by.
Much to their surprise, they do sometimes get single events (no coincidence)
virtually identical to the original Cabrera signal.  And although the absense
of coincidence rules out an actual monopole, nobody knows how to actually make
it happen on purpose!)  

So Cabrera, without ever understanding what went wrong, eventually published a
retraction of his claim, and also published a tight upper limit on the possible
monopole flux near the Earth based upon his newer experiments.  

Bottom line - experiments are complicated and not always completely understood. 
You can find experiments in the literature which contradict almost any 
physics statement you care to make, many of which go unrefuted, but eventually
are disregarded in the face of contrary overwhelming data, or simple inability 
to reproduce the results.

-Scott
-------------------- 
Scott I. Chase 
SICHASE@CSA2.LBL.GOV