On Wed, Jun 12, 2013 at 12:35 PM, Bruno Marchal <marc...@ulb.ac.be> wrote: > > On 12 Jun 2013, at 11:20, Telmo Menezes wrote: > >> On Wed, Jun 12, 2013 at 11:17 AM, Bruno Marchal <marc...@ulb.ac.be> wrote: >>> >>> >>> On 11 Jun 2013, at 23:18, John Mikes wrote: >>> >>> Laughing stock: how can so many excellently educted and smart(est) >>> scientists SERIOUSLY debate on farces like flying pink elephants? >>> >>> >>> >>> Those are test cases, extreme case, to argue more easily on the question >>> of >>> existence, which is not obvious. >>> Of course we are not discussing on the existence of flying elephants at >>> all. >> >> >> Maybe on a smaller planet with less gravity or a denser atmosphere >> flying elephants would be a viable evolutionary niche? > > > You will not help John!
I know, couldn't resist :) > But the problem with your answer, is: what do you mean by "elephant". On > that smaller planet elephant might be called "bird". Well, maybe something that triggers the classification of "elephant" on a majority of human brains? Something that looks like this: http://i249.photobucket.com/albums/gg237/unbelivablybored/Montagebilledecopy.jpg > Can a dinosaur fly? Yes, they are called bird, but they are descendent of > dinosaurs. But here some genomic can be invoked for establishing some > identity or parental relation. > > With enough "IF" you can deduce what you want. If some dictator renamed the > bird as "elephant", then surely elephant can fly. > > Bruno > > > > > > >> >> Telmo. >> >>> Bruno >>> >>> >>> >>> >>> 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/ >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> 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+unsubscr...@googlegroups.com. >>>> To post to this group, send email to everything-list@googlegroups.com. >>>> Visit this group at >>>> http://groups.google.com/group/everything-list?hl=en. >>>> 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 everything-list+unsubscr...@googlegroups.com. >>> To post to this group, send email to everything-list@googlegroups.com. >>> Visit this group at http://groups.google.com/group/everything-list?hl=en. >>> For more options, visit https://groups.google.com/groups/opt_out. >>> >>> >>> >>> >>> 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 everything-list+unsubscr...@googlegroups.com. >>> To post to this group, send email to everything-list@googlegroups.com. >>> Visit this group at http://groups.google.com/group/everything-list?hl=en. >>> 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 everything-list+unsubscr...@googlegroups.com. >> To post to this group, send email to everything-list@googlegroups.com. >> Visit this group at http://groups.google.com/group/everything-list?hl=en. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> > > 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 everything-list+unsubscr...@googlegroups.com. > To post to this group, send email to everything-list@googlegroups.com. > Visit this group at http://groups.google.com/group/everything-list?hl=en. > 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. 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