X-Message-Number: 15304
From: 
Date: Tue, 9 Jan 2001 13:41:34 EST
Subject: Addendum 2

To clarify a couple of things:

First, Platt is trying to have it both ways. On the one hand, he is saying, 
if the current CPA used by Alcor is somewhat less toxic than a vitrifiable 
solution of glycerol, that is extremely important. On the other hand, if that 
Alcor solution results in less than 53% viability, that really isn't so bad, 
since maybe "53% viable" means all cells are functioning at half normal, and 
cells half dead can recover. 

Quantitatively, of course, any improvement is an improvement, and any deficit 
is a deficit. Bigger improvements are more important than small improvements, 
and bigger deficits are worse than small deficits. Translating that into 
projections about overall probabilities, in light of future resources, is 
another matter entirely. Platt thinks he is qualified to make guesses worthy 
of respect, even though he has never made a calculation of probability. 
Again, see our website on probability of revival. 

Second, Platt assumes that only vitrification can work, not freezing, and 
certainly not freezing by any of the older or simpler methods. Well, let's 
look at statements officially made in 1988 by the scientist Platt holds in 
highest esteem. For more extensive quotations and citations, see our web 
site; for the moment, look at this passage:

"A reasonable way of summarizing the world literature on the subject at 
present is to say that whenever either brain structure or brain function has 
been evaluated after freezing to low temperatures and thawing, robust 
preservation has almost always been demonstrable provided that some attention 
was paid to providing at least token cryoprotection, and in some cases good 
preservation has been documented in the complete absence of reasonable 
cryobiological technique."

Certainly this is not definitive or conclusive. But as a general assessment 
we clearly have on the one hand Platt's personal pessimistic view of 
procedures he wants to denigrate, and the optimistic view of the person he 
acknowledges to be one of the world's leading authorities on cryopreservation 
of the brain. 

If you want to base your actions on "authority" you can take your pick 
between Platt, his main man, or anyone else. If you want to judge the facts 
and gauge the probabilities for yourself, study our web site.

Robert Ettinger
Cryonics Institute
Immortalist Society
http://www.cryonics.org

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