Le 04-janv.-06, à 19:30, Brent Meeker a écrit :

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Bruno Marchal wrote:Hi John,I think you may have problems because you are not used neithertrained in axiomatic thinking. The idea consists in NOT defining theobjects we want to talk about, and keeping just some neededproperties from which we prove other theorem.Let me give an example with the idea of knowledge. Many philosophersagree that knowledge should verify the following law, and I take itas the best definition of knowledge we can have:1) If I know some proposition then that proposition is true 2) If I know some proposition then I know that I know that proposition3) If I know that some proposition a entails some proposition b, thenif I know a, I will know b.But that doesn't capture meaning of "know".

`But nobody knows or agree on the *meaning* of "know", that's was my`

`point. If *you* think it leaves something out, for a mathematician it`

`means that you agree with the definition!`

And then you propose a stronger theory by adding 4:

It leaves out 4) If I know some proposition then I have experiencecausally connected to the fact that makes it true. See c.f. Gettier'sparadox.

`Now, that "4" *is* problematical because it refers to a undefined`

`notion of causality, which itself can only be defined axiomatically.`

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