From: mcgrath@cs.uiuc.edu (Robert McGrath)
Subject: Re: Help
Reply-To: mcgrath@cs.uiuc.edu
Organization: University of Illinois, Dept of Computer Science
Date: Mon, 23 Nov 1992 22:13:06 GMT

In article <1992Nov19.183104.29669@Princeton.EDU>, rdnelson@phoenix.Princeton.EDU (Roger D. Nelson) writes in part:
|> a cursory
|> examination shows that all the studies were small, hence subject to
|> so-called Beta error, namely the conclusion that no effect exists when
|> there is a real effect.  This happens at a predictable rate in
|> experiments that have insufficient statistical power, and in the psi
|> business, because the putative effects are by any standard very small,
|> the majority of experiments are too weak to reliably detect effects.  
But then there is the "excessive-Beta" effect, which is that, with
enough statistical power you will surely find SOMETHING, whether it is
there or not.  (:-) Not meant as a totally serious criticism, although 
there is a definite kernel of truth to this argument.)

I expect SB would say "no evidence for psi" rather than "no psi".
Also, SB's conclusion of 'n. e. f. p.' is based not only on her
inability to produce psi in her own studies, but upon examination
of the body of psi research.  Thus, her case for concluding 'no
psi' is not quite as weak as you suggest--she has explicitly rejected 
much of the recent work as methodologically unsound.   (I know RDN
would not agree with SBs assessment in all cases.)

|> Without going into some detail, my jumping in can only point in a
|> direction that amounts to suggesting that while Blackmore is a good
|> researcher in most respects, her real forte is in writing good prose
|> explaining fringe topics.  The explanations are not necessarily correct,
Be careful about what you say about SB, as I have a bit of an
intellectual crush on her. :-)

I would say that, beyond writing well, her most important contributions
are 1) taking "fringe" topics seriously without losing the respect of
"mainstream" psychologists (which ain't easy) and 2) making some very 
solid efforts to relate "conventional" cognitive/physiological psychology 
to "fringe" topics such as OBEs, NDEs, and perceptions of psychic events.
 
Item (2) does not "dispose of" psi hypotheses, but does offer, as
you note, "workable and sometimes testable hypotheses", some of which
have much merit as non-psi "explanations" of some (SOME) experiences 
suggested as evidence for psi.  She has stated that she is pleased
that her approach has produced "progress", that is, new findings
and hypotheses, which she feels has not happened with the conventional
'psi' hypothesis.  Whether this "positivist progress" is real or important, 
the perception of the same is definitely a characteristic of SB's work!

|> There are, of course other possible explanations for Blackmore's failure 
|> to find evidence, including the one she has chosen, namely, no psi.  
|> She might agree, however, that her own research was not an adequate
|> basis for drawing that conclusion.

She has frequently said this.  

In some cases, however, she has offered psychlogical hypotheses incompatible 
with 'psi', and she presumably feels justified in rejecting 'psi' in favor 
of such hypotheses when alternative hypotheses are supported by reasonable
evidence.

-- 
  Robert E. McGrath
  Founder, President, and Only Member of the Central Illinois
  Susan Blackmore Fan Club
  Urbana Illinois
  mcgrath@cs.uiuc.edu