Hal Finney wrote: > Joao Leao, <[EMAIL PROTECTED]>, writes: > > You are quite right in one point, Hal: "...probably a lot of > > things!". But you should have written: "Certainly > > a lot of things, each one with high probability". If you pick > > photons rather than, say, flying massive debris, you should > > in all honesty, include photons along all the spectrum > > including, of course, gamma rays, which will kill you not > > just now, but keep on killing softly you forever by blasting the > > nuclear structure of your atoms and persuading them to > > decay. You would conclude that if you survive the blast, > > you would, with the help of QM be able to calculate precisely > > how dead you already are! > > I'm not sure if you are joking here; do you agree that even gamma > ray photons may happen to miss your body due to the quantum randomness > in their emission and absorption events?
I was joking but not entirely. It is very tempting for people to talk about "quantum probabilism" in the way you do here, that is, by using an analogy with classical equilibrium statistical emsembles where even the most improbable event has a small but non infinitesimal chance of occurring. This, however is incorrect. Unlike Stat Mech, Quantum mechanics can, and does, predict definite events (with prob=1) and does so in many classical situations where classical mechanics cannot not! Yakir Aharonov and his students made and artform of discovering examples of this style of Quantum Magic!... The thing is: QM probability distributions evolve in time and most spectra are discrete... so this fetching world of monkeys and typerwiters does not apply. My point is that, probabilistically or otherwise, a gamma ray kills you much more surely than any single bullet if you compare not only the scattering corsssections but also the long term effects. That may have something to do with the fact that "gamma emmiters" are under stricter control than handguns... > > > So there is a branching event for you: if you survive a nuclear > > blast, how sure could you be that you really survived? > > Which brings up another possibility, which is that your body could > spontaneously re-assemble from atoms in the environment even if it were > temporarily destroyed. In that case you might have genuine uncertainty > as to whether you really survived, depending on your views of personal > identity and survival. Now, that is a joke! Wait! I think that just happened to me! > > Hal Kindly, -Joao -- Joao Pedro Leao ::: [EMAIL PROTECTED] Harvard-Smithsonian Center for Astrophysics 1815 Massachussetts Av. , Cambridge MA 02140 Work Phone: (617)-496-7990 extension 124 Cell-Phone: (617)-817-1800 ---------------------------------------------- "All generalizations are abusive (specially this one!)" -------------------------------------------------------
