On Thu, Sep 12, 2013 at 5:56 PM, Bruno Marchal <[email protected]> wrote: > > On 12 Sep 2013, at 11:33, Telmo Menezes wrote: > >> Time for some philosophy then :) >> >> Here's a paradox that's making me lose sleep: >> http://en.wikipedia.org/wiki/Unexpected_hanging_paradox >> >> Probably many of you already know about it. >> >> What mostly bothers me is the epistemological crisis that this >> introduces. I cannot find a problem with the reasoning, but it's >> clearly false. So I know that I don't know why this reasoning is >> false. Now, how can I know if there are other types of reasoning that >> I don't even know that I don't know that they are correct? > > > > Smullyan argues, in Forever Undecided, rather convincingly, that it is the > Epimenides paradox in disguise, and so it can be said to be solved in the > same way (by Tarski theorem and Gödel's theorem), at least for > self-referentially correct machine. > > I can follow Smullyan here, but I think also that this form of Epimenides, > by the use of time, run probably deeper, and that it might lead to deeper > explanations. In fact intensional fixed point à-la-Rosser are probably > closer to it (we might come back on this, it is technical).
Thanks Bruno! I really have to find some time to read Forever Undecided, and hope you can come back to the intensional fixed point. Telmo. > Best, > > Bruno > > > http://iridia.ulb.ac.be/~marchal/ > > > > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
