> On 8 May 2018, at 01:32, John Clark <johnkcl...@gmail.com> wrote: > > On Mon, May 7, 2018 at 12:58 PM, Bruno Marchal <marc...@ulb.ac.be > <mailto:marc...@ulb.ac.be>> wrote: > > > in some model CH is true (Gödel) and in some model CH is false (Cohen). > > That is incorrect. Godel showed that if the CH is false it would not produce > any contradictions in Zermelo–Fraenkel set theory plus the Axiom Of Choice > (ZFC), but that does not prove that the CH is false.
OK, but that is prove by building a model where CH is false, like we can prove the independence of Euclid postulate by building a model satisfying all axioms + the negation of the parallel postulate. The notion of truth is always relativised to a model, in logic. Bruno > And Cohen proved that if the CH is true it would not produce any > contradiction in ZFC, but that doesn't prove its true either. What the two of > them did prove is that ZFC has nothing to say about Continuum Hypothesis, it > just doesn't know if its true or not. > > And I think you're confused about the difference between what a model says > and what reality says. One model may say you can safely march across that > bridge and another model might say the bridge will collapse, but it makes no > difference which model you believe when you cross that bridge, it will > either fall down or it won't. > > John K Clark > > > > > > > > -- > 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 > <mailto:everything-list+unsubscr...@googlegroups.com>. > To post to this group, send email to everything-list@googlegroups.com > <mailto:everything-list@googlegroups.com>. > Visit this group at https://groups.google.com/group/everything-list > <https://groups.google.com/group/everything-list>. > For more options, visit https://groups.google.com/d/optout > <https://groups.google.com/d/optout>. -- 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 https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
