> On 21 Oct 2018, at 17:43, Tomas Pales <[email protected]> wrote: > > > > On Sunday, October 21, 2018 at 4:28:21 PM UTC+2, Philip Thrift wrote: > > "reality contains all mathematical objects" > > > Ironically, Tegmark doesn't believe that at all. He says infinite > mathematical entities are "ruining physics". > - http://blogs.discovermagazine.com/crux/2015/02/20/infinity-ruining-physics/ > <http://blogs.discovermagazine.com/crux/2015/02/20/infinity-ruining-physics/> > > > The only thing to conclude is that Mad Max published his mathematical > universe hypothesis as a joke! > - https://en.wikipedia.org/wiki/Mathematical_universe_hypothesis > <https://en.wikipedia.org/wiki/Mathematical_universe_hypothesis> > > Already in his Mathematical Universe paper on arxiv, Tegmark discussed a > restricted version of MUH called CUH (computable universe hypothesis). He > mentioned that the attractive feature of CUH would be the disappearance of > the measure problem and also the exclusion of structures of which we may > never know whether they are consistent (due to Godel's second incompleteness > theorem) and thus whether they exist. On the other hand, the fact that we > cannot calculate probabilities (the measure problem) or find whether a > structure is consistent seems like an epistemic problem, not an ontological > one. The infinities may exist in reality, we just can't extract useful > statistics from them or confirm their existence. But reality doesn't depend > on whether we find it useful or whether we can confirm its existence. > > The universe in which we live, or even the inflationary multiverse, may be a > finite/computable structure but there may also be infinite structures in the > larger mathematical multiverse.
The computable universe hypothesis cannot make sense. To define “computable” you need to assume arithmetic. But arithmetic executes all computations, and the measure problem will have to involve infinities. So the correct passage from “mathematical universe” to computationalism consists in 1) distinguish well the ontology and the phenomenology. Restrict the ontology to the finite and computable finite objects, 2) allowing the infinite in the phenomenology, where indeed the physical universe will appear. The infinities ruins physics only if they are put in the ontology. This is explained in details in basically all my papers (on this subject). I can give the reference (again) if you are interested. Tegmark missed the mind-body problem. Bruno > > -- > 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] > <mailto:[email protected]>. > To post to this group, send email to [email protected] > <mailto:[email protected]>. > 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
