Hi Eric,

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Le 11-août-05, à 01:34, Eric Cavalcanti a écrit :

Hi Bruno, On 8/11/05, Bruno Marchal <[EMAIL PROTECTED]> wrote: I am having a problem understanding this axiom:(...) Lob formula (B(Bp->p)->Bp), the main axiom of the modal logic of self-reference (G) can be interpreted as showing that some form of honest placebo effectworks! But this is something I am still taking with some grain ofsalt.See the book "Forever Undecided" to see Smullyan exploiting theworkingof some self-fulfilling beliefs.Suppose p = "it is raining today"B(Bp->p) is true because I believe that if I believe it is rainingtodayit IS raining today, since If I believe it is raining today it isbecauseI have gone outside and seen that it is raining today, or I believe my source of information for that matter.But it doesn't follow from that that I do believe that it is rainingtoday.It happens by the way that I don't believe it is raining today, because I can see a beutiful sun outside. What's wrong?

Literaly, it means you are less modest than a Lobian machine!

`If B(Bp -> p) was true, it would mean that whatever the poof you have`

`that p is true, then p is true. What about dreaming that you have look`

`through the window and see it rains?`

`(Remember B is not the "incorrigible" first person. B is really for a`

`scientific third person sharable justification). Of course it makes`

`things still more unbelievable, given that you will tell me that in`

`case you have a proof, it is even more amazing you can be wrong. But`

`then it is like that by incompleteness.`

`Now, another remark is that I don't think the B can be used at all for`

`everyday belief which are much more complex due to the long social`

`interaction between us. The everyday beliefs are probably mixture of`

`the logics I described in comp, and which concerns sound machines. But`

`to get physics, this is enough.`

Bruno http://iridia.ulb.ac.be/~marchal/