Modal Logic question...

[Go_Blue88]

Explain why you would not want the following as a modal thesis of the system S5 given that LA --->A is a thesis of S5: A--->LA

The arrow is equivalent to a horeshoe, or in other words, the "if then symbol."

I definitely don't understand this stuff right now. Any help would be appreciated.

[Go_Blue88]

Alright I think I figured it out.

Just because A is true does not entail necessarily that A can be found in all possible worlds. However, if A is found in all possible worlds, then obviously A is true.

[Jshuttlesworth]

Damn. What class is that for?

[quinn]

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Damn. What class is that for?

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I don't know, but at the University of Washington we have a class called "Modal Logic"

[Jshuttlesworth]

[ QUOTE ]
[ QUOTE ]
Damn. What class is that for?

[/ QUOTE ]

I don't know, but at the University of Washington we have a class called "Modal Logic"

[/ QUOTE ]

Probably a decent guess /images/graemlins/smirk.gif
Thanks

[bearly]

modal logics are just what the title suggests. that is, they are not truth/functional logics. one modality could be "knowledge" another "belief", a third could be "certainty" (this would be a lulu). so instead of x is true, propositions to be examined might read x knows y. i think you get the drift now................b