X-Message-Number: 9531
From: Ettinger <>
Date: Tue, 21 Apr 1998 11:36:34 EDT
Subject: Pietrzak 6

PIETRZAK 6

Referring to John Pietrzak's Cryonet # 9530, in no particular order:

1. Yes, I misattributed the Fountain of Youth alleged counterexample. Sorry.

2. An important point is that Mr. Pietrzak uses "intuition" in a misleading
way. He seems to imply e.g. that, in attempting to use Bayes' formula, one
either uses some vague inner sense that could vary dramatically between
individuals; or else uses explicit, recorded statistics. Actually, there is an
extremely important intermediate case, where there is no simple or readily
available explicit statistical record, yet the facts are so clear that most
people will be in reasonably close agreement.

An example is the exponential life parameter which I developed in the essay.
It employs the "intuition" that moderate values of expected life are a priori
more likely than extreme values. Who could deny that this is true and
thoroughly grounded in experience? Who could deny that it is useful
information? 

In the same context, Mr. Pietrzak uses "objective/subjective" in a misleading
way. He calls the example above (a priori information about the life
parameter) "subjective," but, as explained above, it is perfectly objective in
the sense that it is firmly rooted in experience and that different observers
are likely to have similar interpretations.     

3. I also noted that Bayes is more objective than (say) Fisher, in the sense
that it does not ignore some useful and available data, even though the data
may be imprecise. If you don't like the word "objective" in this context, then
substitute "scientific." Certainly someone who looks at the whole picture, and
factors in everything relevant, is being more scientific than someone who
doesn't.

4.  Am I appealing to "modus ponens" or to my general approach to probability?
To both, of course. Modus ponens appears at some point in almost every
argument, but is rarely labeled such, because it is so routine. 

The key point, as Mr. Pietrzak says, is whether experience justifies the
statement that "Goals of technology have a good chance of success." This is
not a "different" argument, but the main line and (I thought) clearly labeled
argument. We are appealing to experience by mentally constructing a set of
reasonably similar "experiments." 

Clearly, this is not "circular" reasoning. We look as well as we can at the
record related to projects of technology, then ask whether cryo-repair fits in
reasonably well. If it does, then the ratio of success in the record is an
estimate of the probability of future success in cryo-repair.

Naturally, we must be careful (a) in characterizing "projects of technology"
and (b) in deciding whether cryo-repair fits in reasonably well.

As to (a), the project should be one which at some stage was thought so
difficult as to be either impossible or forever impractical; or else (if
achieved) it should be one which was not even envisioned in somewhat earlier
times. It should also be "serious" in that it does not violate "known" laws of
nature and has at least a few proponents with respectable credentials. (This
would rule out Lysenko's projects, for example.) Finally, the "project" should
be one of ends rather than means--for example, to build a flying machine, not
necessarily to build one that employs a specific means, such as flapping wings
(although that also will doubtless become possible with future materials,
power plants, and stabilizing systems).

As to (b), cryo-repair is certainly serious, and we do not much care whether
the successful means will involve full-fledged nanotech, nearer term chemistry
and biology, or a pragmatic mix of approaches.

If we produce a list of successful projects, some will claim, of course, that
cryo-repair is much more difficult than most of those. This claim can be
countered in several ways. One way is just to point out that cryo-repair is
actually on the road to implementation, in the sense e.g. that definite
progress has been shown in nanotech--whereas many projects have already been
successful that shortly before had not even been imagined. This is not a
perfect argument, but on the whole one must agree that we are more likely to
achieve success in an ongoing project than in one not yet even conceived. 

Remember also, once more, that we refer to the likelihood of EVENTUAL success.
A "failed" project means one which not only has not yet succeeded, but has
been proven to be almost certainly unachievable.

Putting all this together, one obtains a long list of successful projects of
technology, and a very short or empty list of failed projects. When I get
around to adding to the web subsite, I'll be specific. 

Note that all this, really, is more or less equivalent to Feinberg's and
Feynman's propositions that, given enough time and motivation, we can do
anything that natural law permits, including manipulation of matter on the
molecular level. 

Enough for now.

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

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