On 11 January 2014 16:02, meekerdb <meeke...@verizon.net> wrote: > On 1/10/2014 4:06 PM, LizR wrote: > > On 11 January 2014 12:54, meekerdb <meeke...@verizon.net> wrote: > >> On 1/10/2014 1:42 AM, Bruno Marchal wrote: >> >> Second, a reality can exist without being computed. the best and simple >> example is arithmetic. Only a very tiny part of it is computable (this is >> provable if you accept the Church Turing thesis). >> >> But it's questionable whether it "exists". >> > > Does it kick back? Could two beings in different universes, with > different laws of physics (if such exist) discover it independently? > > Of course "discover" begs the question. >
No it doesn't. It *is* the question. I used "discover" in the sense of making a discovery, as opposed to inventing something. If alien mathematicians start from whatever axioms the humans mathematicians start from, and find themselves led inexorably to the same logical conclusion as the humans, then I would say they are "discovering" something about the nature of reality. If they start from the same premises and arrive at a different conclusion (and neither sets of mathematicians have made any mistakes), then I would say they are "inventing" something. That's the sense in which I asked if they would "discover" the (alleged) facts of maths. It seems to me a perfectly reasonable way to ask the question. Would they independently discover the same results, or wouldn't they? What's wrong with that? I suppose I could have assumed my audience were drongoes and added something like "...or would they invent completely different results?" But I didn't bother to insult my audience like that, because it seems to me that was implicit in the way I'd asked the question. In fact I'd very neatly *summarised* the entire question through the use of that one word - "discover". > If so, it exists by any reasonable definition (including Stephen's) > > Two beings with different laws of physics in different universes could > invent the game of rock, paper, scissors. Does that mean the game exists? > Did it exist before they invented it? > That isn't the same as being led to one specific conclusion by applying logic to a given set of axioms, though, which is what "discover" implies. > Does the continuum exist? > I don't know. I assume it exists as a mathematically discoverable entity (or is there a problem with that?) I don't know if it exists in the physical sense of space-time being one. As I mentioned elsewhere recently, the jury is out on this one due to the GRB data still being relatively scarce. Watch this space. -- 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 http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.