helena 
Suspended Member (Idle past 5874 days) Posts: 80 Joined: 03-27-2008
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Message 2 of 3 (88573)
02-25-2004 10:12 AM
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Reply to: Message 1 by Peter 02-25-2004 9:36 AM
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I would say the following (a physicists perspective maybe): Saying something cannot happen and assigning a probability of zero to that event are exactly identical. One might argue that it is pointless to do so but such a zero probability can have some merit. For example: In quantum mechanics you will express the probability for a system for going from state a to state b, which would read (in qm notation): P(a->b)=C*< a|H'|b > where basically a and b are the functions describing states a and b and H' describes the way in which the system is being influenced. The construct <|> is just a short notation for a certain mathematical operation (taking the complex conjugate of a multiplied by the operator multiplied by b and integrating over R3 usually). Such a probability can turn out to be exactly zero for two given states a and b (not approximately but exactly). This then basically tells you that your system will not change from a to b (or vice versa) for the stimulus provided (which is described by H'). So a probability of zero can make a lot of sense...
This message is a reply to: | | Message 1 by Peter, posted 02-25-2004 9:36 AM | | Peter has replied |
Replies to this message: | | Message 3 by Peter, posted 02-26-2004 7:13 AM | | helena has not replied |
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