Laughing stock: how can so many excellently educted and smart(est) scientists SERIOUSLY debate on farces like flying pink elephants? JM
On Tue, Jun 11, 2013 at 12:28 PM, meekerdb <meeke...@verizon.net> wrote: > On 6/11/2013 12:51 AM, Bruno Marchal wrote: > >> >> On 10 Jun 2013, at 20:04, meekerdb wrote: >> >> On 6/10/2013 10:52 AM, Bruno Marchal wrote: >>> >>>> >>>> On 10 Jun 2013, at 18:25, meekerdb wrote: >>>> >>>> On 6/10/2013 12:19 AM, Telmo Menezes wrote: >>>>> >>>>>> On Sun, Jun 9, 2013 at 2:40 PM, Bruno Marchal <marc...@ulb.ac.be> >>>>>> wrote: >>>>>> >>>>>>> On 09 Jun 2013, at 11:20, Telmo Menezes wrote: >>>>>>> >>>>>>> On Sun, Jun 9, 2013 at 9:23 AM, Bruno Marchal <marc...@ulb.ac.be> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> >>>>>>>>> On 08 Jun 2013, at 17:55, meekerdb wrote: >>>>>>>>> >>>>>>>>> On 6/8/2013 1:02 AM, Bruno Marchal wrote: >>>>>>>>> >>>>>>>>> >>>>>>>>> On 08 Jun 2013, at 05:15, meekerdb wrote: >>>>>>>>> >>>>>>>>> On 6/7/2013 4:00 PM, Stephen Paul King wrote: >>>>>>>>> >>>>>>>>> Yes, if there was a text of this it would be nice... I found this: >>>>>>>>> http://plato.stanford.edu/**entries/fictionalism-**mathematics/<http://plato.stanford.edu/entries/fictionalism-mathematics/> >>>>>>>>> >>>>>>>>> >>>>>>>>> A fictionalist account holds that some things are fictional, i.e. >>>>>>>>> don't >>>>>>>>> exist even though their complete description is self-consistent. >>>>>>>>> Everythingists apparently reject this idea. Platonists seem to >>>>>>>>> equate >>>>>>>>> 'true' with 'exists'. If you believe 17 is prime you must believe >>>>>>>>> 17 >>>>>>>>> exists. I think this is wrong. If you believe that a flying pink >>>>>>>>> elephant >>>>>>>>> is pink, must you believe a flying pink elephant exists? >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> Flying pink elephants are pink and not pink. That's why flying pink >>>>>>>>> elephant >>>>>>>>> can't exist. >>>>>>>>> >>>>>>>>> >>>>>>>>> A pink elephant is pink by construction. >>>>>>>>> >>>>>>>>> >>>>>>>>> Exact. But the flying pink elephant are also not pink. By logic. >>>>>>>>> Or show >>>>>>>>> me >>>>>>>>> a flying pink elephant living on this planet which isn't not pink. >>>>>>>>> >>>>>>>> >>>>>>>> Bruno, how are flying pink elephants any different from things that >>>>>>>> I >>>>>>>> remember but am not experiencing this very moment? >>>>>>>> >>>>>>> >>>>>>> I add explanation. Here you describe two 1p events. They are similar, >>>>>>> although I guess you don't have precise memory of having actually >>>>>>> seen a >>>>>>> Flying Pink Elephant in your life, except in cartoon or dreams. >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> For example, I've >>>>>>>> been to Brussels but I'm not there right now. Brussels is an >>>>>>>> abstraction in my mind, but I believe it's the capital of Belgium. >>>>>>>> That's part of the Brussels abstraction, in the same sense that >>>>>>>> being >>>>>>>> pink is part of the flying pink elephant abstraction. No? >>>>>>>> >>>>>>> >>>>>>> >>>>>>> I do not dispute that fact. Pink elephant are pink. >>>>>>> >>>>>>> But the pink elephant on this planet happens also to be brown >>>>>>> rampant worms. >>>>>>> And I'm afraid that is only a classical logician's joke. >>>>>>> >>>>>>> (x = Flying Pink Elephant) -> (x = Brown Rampant Worms) is true on >>>>>>> this >>>>>>> planet because (x = Flying Pink Elephant) is false for all x, on >>>>>>> this planet >>>>>>> (I think), >>>>>>> >>>>>> >>>>> >>>>> But (x = Flying Pink Elephant) is false for all x, is an empirical >>>>> proposition. >>>>> >>>> >>>> I agree. >>>> >>>> >>>> >>>> >>>> Not one you can prove from arithmetic or logic. But the point was >>>>> that true propositions, like "Flying pink elephants are pink" don't imply >>>>> the existence of anything; just like "17 is prime" doesn't imply the >>>>> existence of 17. >>>>> >>>> >>>> But how do you formalize "flying pink elephant are pink" ? >>>> >>>> I am simpled minded, so I formalized it in a first order logical >>>> formula: >>>> >>>> if x is an elephant which is pink and which is flying then x is pink. >>>> >>>> This does not entail Ex( x = an elephant which is pink and which is >>>> flying) >>>> >>>> For the same reason that: >>>> >>>> "if x is a prime number, which is even, and bigger that 3" then x is >>>> bigger than 3" >>>> >>>> does not entail Ex(x = even prime number bigger than 3). >>>> >>> >>> Actually it does. Let y="x is a prime number which is even and bigger >>> than three". Then, if y anything; in classical logic everything follows >>> from a contradiction. But we were talking about the metalogical relation >>> of true/false and fictional/real. I don't think two are parallel. It's >>> true that 17 is prime - but it doesn't follow that 17 is real. It's true >>> that Sherlock Holmes lived on Baker Street, but it doesn't follow that he >>> existed. >>> >> >> The difference comes from the fact that in arithmetic e can prove Ex(x = >> 17), but we cannot prove in your "theory" that Ex(= Sherlock Holmes). >> > > But "E" in those two propositions don't have the same meaning. In the > first it means that the axioms of arithmetic imply there is an x=17. In > the second it means there was person who had all or most of the > characteristics described in Conan Doyle's stories. > > >> >> >> >> >> >> Of course something described by a contradiction can't exist. But a >>> contradiction is dependent on an axiomatic system. So a pink elephant >>> doesn't exist, but "There is a pink elephant." is not a contradiction; it's >>> just a falsehood and it's not the case that everything follows from a >>> falsehood. >>> >> >> It is the case that everything follows from a falsehood. (0=1) does >> implies everything. >> > > In classical logic. But logic is just supposed to formalize good > reasoning. "There is a pink elephant." may mean no more than "That looks > like an elephant painted pink." It's not an axiom of a formal system. I > deliberately included "flying" because it makes the identification as > "elephant" problematic. If we found an animal that looks like an elephant > painted pink, we'd certainly call it a "pink elephant". But if we found an > animal that looked like an elephant with wings that could fly, we'd only > call it a "flying elephant" metaphorically. > > Brent > > >> f -> q is a tautology. It is equivalent with ~f V p. that is with t V q. >> >> "p -> everything" in all words where p is false, even if there are worlds >> were p is true. >> > > -- > 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 > everything-list+unsubscribe@**googlegroups.com<everything-list%2bunsubscr...@googlegroups.com> > . > To post to this group, send email to > everything-list@googlegroups.**com<everything-list@googlegroups.com> > . > Visit this group at > http://groups.google.com/**group/everything-list?hl=en<http://groups.google.com/group/everything-list?hl=en> > . > For more options, visit > https://groups.google.com/**groups/opt_out<https://groups.google.com/groups/opt_out> > . > > > -- You received this message because you are subscribed to the Google Groups "Everything List" group. 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