X-Message-Number: 8257 From: Date: Fri, 30 May 1997 12:09:07 -0400 (EDT) Subject: probability, psychiatry Perry Metzger (# 8251) shows his limited understanding of the foundations of probability theory. My own view, developed independently about 45 years ago, turns out to be similar in some ways to those of important historical figures including Frechet and Reichenbach. It was presented as an essay for the M.A. in math, and pronounced kosher by professionals in the field. A partial version of it is available from the Immortalist Society in the form of a booklet: CRYONICS: THE PROBABILITY OF RESCUE. I won't say much here, but note that Metzger says of certain assertions that they are "true or false" and there exists no statistical background on which to base probability assessments. He is wrong. Very briefly: First, every assertion of alleged fact is true or false; this obviously does not make probability inapplicable. As one obvious example, consider coin tossing. The probability of getting heads on the next toss is (usually, approximately) 1/2; no one disagrees. But now consider a coin already tossed but not yet examined. According to Metzger's reasoning, this is beyond the purview of probability; we either have heads or we don't. But for purposes of betting, the situation is exactly the same as in the case of a future toss, and we use probability in the same way. Probability is objective in the sense of resting on experience, but subjective in the sense that it depends on the experience of the OBSERVER. Second, Metzger's notion of a necessary statistical basis is simplistic. We do need such a basis, but if necessary we can look at broadened categories. As an extremely simple example, some considerations in probability calculations (or making bets) apply not only to football games but also to basketball games. If I invent a new kind of ball game, with no background of experience, is use of probability out of the question? Of course not; I just look at the broader category of ball games in general (which may or may not require rougher calculations). If someone says an invisible bunny is following him around, is there any way to judge the probability that the assertion is true? Again, certainly. We know from experience that people frequently make such statements either as jokes or as an illustration of some theoretical argument. Since we have minimal reason to believe the assertion and plenty of reason to reject it, there is an overwhelming probability that the assertion is false. This is just a short-hand application of the general principle noted above....And anyone who claims not to subscribe to this principle will have to explain why, in practice, he uses it every day in countless ways. P.S. Metzger also does me the kindness of psychiatric evaluation without charge, saying my skepticism about feeling in robots is based on "religion" or on a need to feel superior. How this conclusion can be reached from reading anything I have said is itself a psychiatric problem. Robert Ettinger Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=8257