> On 13 Nov 2018, at 11:06, Philip Thrift <cloudver...@gmail.com> wrote: > > > > On Monday, November 12, 2018 at 8:35:23 PM UTC-6, Bruno Marchal wrote: > > A model is a model of a theory. The notion of model of a model can make > sense, by considering non axiomatisable theory, but that can lead to > confusion, so it is better to avoid this. When a model is seen as a theory, > if it contains arithmetic, the theory cannot be axiomatised, proofs cannot be > checked, the set of theorems is not recursively enumerable, etc. > > > Bruno > > > > This is why some have mathematical theories (alternatives to ZF) that have > finite (i.e. Only a finite number of numbers needed!) models (e.g. Jan > Mycielski, "Locally Finite Theories" [https://www.jstor.org/stable/2273942 > ]). In this approach quantifiers are effectively replaced by typed > quantifiers, where the type says "this quantifier ranges over some finite > set". > > Another approach is to nominalize physical theories theories (Hartry Field, > Science Without Numbers, summary [ > http://www.nyu.edu/projects/dorr/teaching/objectivity/Handout.5.10.pdf ]). In > this approach the model of the theory is a finite set of (references to) > physical objects. > > This is the best point-of-view to have: The set of natural numbers simply > doesn't exist!
I agree. It is actually a consequence of mechanism. The set of natural numbers does not exist, nor any infinite set. But that does not make a physical universe into something existing. Analysis, physics, sets, … belongs to the numbers “dreams” (a highly structured set, which has no ontology, but a rich and complex phenomenological accounts). I gave my axioms (Arithmetic, or Kxy = x, Sxyz = xz(yz)). As you can see, there is no axiom of infinity. Bruno PS Sorry for the delay. > > - pt > > > > -- > 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 email@example.com > <mailto:firstname.lastname@example.org>. > 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 email@example.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.