# Re: The role of logic, & planning ...

```George,
I spent a while poring over Bruno's thesis, and borrowed
Boolos from a local university library to udnerstand more what it was
about. I didn't go into too great a length into the results and
structure of Modal logic, although I gained an appreciation, and an
understanding of the symbology.```
```
However, my main problem with Bruno's work lay not in the technical
details of Model logic, rather with the phrases of the ilk "We
modelise knowledge by Bew(|p|)". I can appreciate its only a model,
but why should I believe that model of knowing has any connection with
reality?  I'm afraid none of the Booloses, nor Bruno's posting helped
me with this.

Cheers

George Levy wrote:
>
> Hi Marchal,
>
> This is a reply to your last two posts. I hope other everythingers beside
> myself are attempting to follow this adventure in logic. It appears to be
> really worth the effort. Please feel free to contribute to this exchange.
>
> Marchal wrote:
>
> And we have as results (including the exercices!):
>
>  > Any frame (W,R) respects K
>  >A frame (W,R) respects T iff  R is reflexive
>  >A frame (W,R) respects 4 iff R is transitive
>  >A frame (W,R) respects 5 iff R is euclidian
>  > (where R is Euclidian means that if xRy and xRz then yRz,  for x, y z
> in W).
>  >A frame (W,R) respects D iff (W,R) is ideal
>  >A frame (W,R) respects C iff (W,R) is realist.
>
> >We will talk on the semantics of L and Grz later.
>
> I do not think you defined euclidian.... There is obviously a connection
> to geometry but I dn't see it.
>
>
> > Actually we will need also
> >
> >          -Predicate logic, and arithmetics
> >          -weak logics (intuitionist logic, quantum logic)
> >          -Algebraic semantics of weak logics
> >          -Kripke semantics of weak logics
> >
>
> I guess we have to visit the whole Louvre to get to the Mona Lisa :-). Any
> short cut?
>
> > Then the interview itself will begin. We can follow the historical
> > progress of that interview:
> >
> >          -Goedel's theorem;
> >          -Loeb's theorem;   (just this one makes the travel worth!)
> >          -Solovay's theorem;
> >          -Muravitski & Kusnetsov, Boolos, Goldblatt theorems;
> >          -Other theorems by Goldblatt
> >          -Still Other theorems by Goldblatt.
> >          -Visser's theorem;
> >
> > It is the theorem by Solovay which will make clear the relation
> > between provability logic and some modal logics.
> > Boolos, Goldblatt, Visser has found result which will make part
> > of our the translation of the UDA argument almost transparent.
>
> Thank you for outlining a itinirary for our journey into logic.... I
> thought our destination was much closer.. Does it have to be that
> complicated? Thanks for the effort.
>
> George
>
>

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