X-Message-Number: 9490
From: Ettinger <>
Date: Wed, 15 Apr 1998 10:18:27 EDT
Subject: Pietrzak's Errors


John Pietrzak (Cryonet #9489) makes fundamental errors and badly
mischaracterizes my approach to probability theory, even though he has made a
valiant effort to understand my essay, "Cryonics: The Probability of Rescue."

He ends by saying, "Unless I've missed my mark completely, this twenty page
thesis comes just about as close to circular reasoning in its conclusion as
I've ever seen." Well, he has indeed missed the mark, and there is nothing in
the least circular about the reasoning. Aside from advising him to read it
again, more carefully, perhaps I can jog him (and any similar others) a bit as

The essence of his error is in the sentences, "He's essentially trying to give
a large probability to the success of intuition…"  and "…we  now use our
intuitive knowledge of cryonics and apply it (a priori) to a probability
function which has…no samples at all!"

That last is the exact opposite of the implicit and explicit thrust of the
essay. There MUST be samples (prior experience) on which to base any estimate
of probability. 

His confusion arises from the fact that intuition is often correct, although
imprecise, because (unconsciously) it DOES rely on experience, on recollection
of prior observations. For EXPLICIT application of the method, one DOES
compile statistics; but often the thrust of experience is so obvious that
compiling statistics would be a waste of time. 

(For example, we don't run in front of oncoming cars when they are close and
moving rapidly, because our remembered experience suggests that this would be
a bad idea. We could, if pressed, PROVE this is a bad idea by compiling
statistics, but it is so obvious that we don't need numbers on paper.)

John quotes from my summary, in part: "In the modern era, not a single goal of
science, so far as I know, has been shown to be impossible…."  Perhaps I
should have added another long section to include a statistical summary, but
it hardly seemed necessary. Maybe someone else would like to play with that.

Incidentally, John mentions my technical example (the exponential life
parameter, which has passed muster with experts in statistics), but fails to
see that it is closely related to the summary as applied to cryonics. If he
still can't see that, after trying again, I can only shrug and hope others
will do better.

Robert Ettinger
Cryonics Institute
Immortalist Society

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