On Sat, Sep 27, 2014 at 03:43:56PM +0200, Platonist Guitar Cowboy wrote: > On Sat, Sep 27, 2014 at 8:29 AM, Russell Standish <li...@hpcoders.com.au> > wrote: > > > On Sat, Sep 27, 2014 at 05:33:00AM +0200, Platonist Guitar Cowboy wrote: > > > On Sat, Sep 27, 2014 at 3:39 AM, Russell Standish <li...@hpcoders.com.au > > > > > > wrote: > > > > > > So I don't see: robust universe => all integers exist > > > > Nor do I. But then that is the exact inverse of what I stated: the > > arithmetic reality assumption in COMP entails a robust reality (one in > > which the UD runs to completion). > > > > If I remember the thesis correctly, than robust is a placeholder for some > grandmother notion of physical reality, with enough consistency in > historical/spatial/causal relations to allow the UD to run. Once reversal > step is reached, the notion is dropped and isn't further needed.
I think you're thinking of the term "concrete", which was somehow synonymous with "primitive physical". This term was always problematic, as neither "concrete", "primitive" nor "physical" were ever defined. I could not understand why the integers, which were supposed to exist, could not satisfy "primitive physicality". What is true, however, is that if the universe is robust, then the reversal holds - whatever it is that is primitive, the only property that is relevant to phenomenal physics is Turing completeness. This seques into the ontological problem that Jean de la Haye brings up - and so does David Deutsch in his own way. If the primitive universe were something like the Hilbert hotel, then we would expect that the sorts of computations available in our empirical reality to include hypercomputations - computations that go beyond the ability of Turing machines. It is a fact that these hypercomputations are conspicuously absent, so that raises the obvious question: why is the primitive ontology restricted to just Turing complete systems? > > Therefore I can't see bi-conditional implication or material implication > either way between the extravagant "for all practical purposes robust > assumption" and properties of arithmetic in terms of ultrafinite, > infinities etc. PGC > When you say "for all practical purposes robust assumption" is extravagant, are you arguing for ultrafinitism? This seems to contradict your name. If you are truly Platonist, your reality is robust. The weaker "for all practical purposes robust" shouldn't be a problem for you. The point of the FAPPRA is that it also includes finite, but large multiverses, like the 10^500 string landscape. Cheers -- ---------------------------------------------------------------------------- Prof Russell Standish Phone 0425 253119 (mobile) Principal, High Performance Coders Visiting Professor of Mathematics hpco...@hpcoders.com.au University of New South Wales http://www.hpcoders.com.au Latest project: The Amoeba's Secret (http://www.hpcoders.com.au/AmoebasSecret.html) ---------------------------------------------------------------------------- -- 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. For more options, visit https://groups.google.com/d/optout.
