On 11 January 2014 16:02, meekerdb <[email protected]> wrote: > On 1/10/2014 4:06 PM, LizR wrote: > > On 11 January 2014 12:54, meekerdb <[email protected]> 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
