>An interesting article by Ken Olum can be obtained from: > >http://xxx.lanl.gov/abs/gr-qc/0009081 > >In short you don't get any information by observing your age, because you >made two observations: > >1) I exist > >2) I am one year old > >When you compute your updated probability distribution according to Bayes' >theorem by taking into account 1) and 2), you find that the updated >probability distribution is the same as the original one. > >The mistake is to use 2) and omit 1). > >Nick Bostrom has argued against including 1) (Self Indicating Axiom) in >Bayesan reasoning. This leads to all sorts of nonsensical results. E.g.: > [...] Interesting paper, thanks. I appreciate very much the idea to put "existing" and possible on the same setting. It is that very idea that I translate in arithmetic, when I go from the thaetetus idea of 1-knowledge, where p is known if p is provable and true: provable(p) & p (p & p) toward the 1-plural measure: provable(p) & consistent(p) (p & <>p) Consistency is the arithmetical version of possibility. Note that G* can prove that provable(p) entails p, and provable(p) entails consistent(p). But G, which represents the machine from its own perspective cannot. (ex: The machine cannot prove provable(f) -> f because this is equivalent to "not provable(f)" which is equivalent to its consistency, which is unprovable (by the consistent machine)). Bruno PS I hope everyone can verify with truth table that (p -> f) is equivalent with (not p). I recall f is the constant false, and t is the constant true.