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Groups > comp.lang.python > #110252 > unrolled thread

Can math.atan2 return INF?

Started bySteven D'Aprano <steve@pearwood.info>
First post2016-06-22 03:50 +1000
Last post2016-06-23 15:37 +0100
Articles 20 on this page of 84 — 19 participants

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  Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-06-22 03:50 +1000
    Re: Can math.atan2 return INF? pdorange@pas-de-pub-merci.mac.com (Pierre-Alain Dorange) - 2016-06-21 20:01 +0200
      Re: Can math.atan2 return INF? Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-06-21 21:32 +0300
        Re: Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-06-22 11:40 +1000
          Re: Can math.atan2 return INF? Nagy László Zsolt <gandalf@shopzeus.com> - 2016-06-27 15:27 +0200
      Re: Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-06-22 11:38 +1000
        Re: Can math.atan2 return INF? pdorange@pas-de-pub-merci.mac.com (Pierre-Alain Dorange) - 2016-06-22 08:21 +0200
        Re: Can math.atan2 return INF? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-06-22 16:34 +0100
          Re: Can math.atan2 return INF? Random832 <random832@fastmail.com> - 2016-06-22 12:19 -0400
          Re: Can math.atan2 return INF? pdorange@pas-de-pub-merci.mac.com (Pierre-Alain Dorange) - 2016-06-22 19:18 +0200
            Re: Can math.atan2 return INF? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-06-22 20:17 +0100
              Re: Can math.atan2 return INF? Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-22 12:50 -0700
              Re: Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-06-23 13:59 +1000
                Re: Can math.atan2 return INF? Dan Sommers <dan@tombstonezero.net> - 2016-06-23 04:40 +0000
                  Re: Can math.atan2 return INF? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-23 16:45 +1000
                    Re: Can math.atan2 return INF? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-06-23 15:39 +0100
                      Re: Can math.atan2 return INF? alister <alister.ware@ntlworld.com> - 2016-06-23 15:04 +0000
                        Re: Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-06-24 02:44 +1000
                          Re: Can math.atan2 return INF? pdorange@pas-de-pub-merci.mac.com (Pierre-Alain Dorange) - 2016-06-23 19:14 +0200
                            Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-23 20:22 +0300
                              Re: Can math.atan2 return INF? pdorange@pas-de-pub-merci.mac.com (Pierre-Alain Dorange) - 2016-06-24 09:53 +0200
                                Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-24 13:38 +0300
                                  Re: Can math.atan2 return INF? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-26 11:43 +1200
                              Re: Can math.atan2 return INF? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-26 11:40 +1200
                                Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-26 10:09 +0300
                                  Re: Can math.atan2 return INF? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-27 11:08 +1200
                                    Re: Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-06-27 12:59 +1000
                                      Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-27 09:40 +0300
                                        Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-06-27 06:15 -0700
                                          Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-27 16:45 +0300
                                            Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-06-27 07:01 -0700
                                              Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-27 17:12 +0300
                                                Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-06-27 07:27 -0700
                                                  Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-27 20:03 +0300
                                          Re: Can math.atan2 return INF? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-28 18:12 +1200
                                            Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-06-27 23:25 -0700
                                            Re: Can math.atan2 return INF? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-28 16:27 +1000
                                        Re: Can math.atan2 return INF? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-28 18:12 +1200
                                          Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-28 09:23 +0300
                                      Re: Can math.atan2 return INF? Random832 <random832@fastmail.com> - 2016-06-28 09:39 -0400
                                        Re: Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-06-29 01:22 +1000
                                        Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-28 19:36 +0300
                                        Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-28 19:42 +0300
                                Re: Can math.atan2 return INF? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-29 19:35 +1000
                                  Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-29 13:54 +0300
                                    Re: Can math.atan2 return INF? Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-29 18:33 -0700
                                      Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-06-29 19:13 -0700
                                        Re: Can math.atan2 return INF? Chris Angelico <rosuav@gmail.com> - 2016-06-30 12:38 +1000
                                        Re: Can math.atan2 return INF? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-30 18:24 +1000
                                          Re: Can math.atan2 return INF? Andreas Röhler <andreas.roehler@online.de> - 2016-06-30 11:35 +0200
                                            Re: Can math.atan2 return INF? Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-30 02:42 -0700
                                              Re: Can math.atan2 return INF? Andreas Röhler <andreas.roehler@online.de> - 2016-06-30 12:13 +0200
                                          Re: Can math.atan2 return INF? Andreas Röhler <andreas.roehler@online.de> - 2016-06-30 12:11 +0200
                                            Re: Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-07-01 03:18 +1000
                                          Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-06-30 08:28 -0700
                                            Re: Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-07-01 04:03 +1000
                                              Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-07-01 07:19 -0700
                                                Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-07-01 18:20 +0300
                                              Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-07-29 22:46 -0700
                                                Re: Can math.atan2 return INF? Steven D'Aprano <steve@pearwood.info> - 2016-08-01 12:53 +1000
                                                  Re: Can math.atan2 return INF? Paul Rubin <no.email@nospam.invalid> - 2016-07-31 20:41 -0700
                                                    Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-07-31 20:54 -0700
                                                  Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-07-31 21:05 -0700
                                                    Re: Can math.atan2 return INF? Ian Kelly <ian.g.kelly@gmail.com> - 2016-08-01 01:05 -0600
                                          Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-07-24 19:48 -0700
                                      Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-30 09:24 +0300
                                        Re: Can math.atan2 return INF? Rustom Mody <rustompmody@gmail.com> - 2016-06-29 23:29 -0700
                                          Re: Can math.atan2 return INF? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2016-06-30 07:47 -0400
                                        Re: Can math.atan2 return INF? alister <alister.ware@ntlworld.com> - 2016-06-30 14:54 +0000
                                      Re: Can math.atan2 return INF? Paul Rubin <no.email@nospam.invalid> - 2016-06-29 23:57 -0700
                                        Re: Can math.atan2 return INF? Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-30 00:16 -0700
                                          Re: Can math.atan2 return INF? Paul Rubin <no.email@nospam.invalid> - 2016-06-30 00:32 -0700
                                            Re: Can math.atan2 return INF? Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-30 00:39 -0700
                                          Re: Can math.atan2 return INF? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-30 18:27 +1000
                                      Re: Can math.atan2 return INF? Andreas Röhler <andreas.roehler@online.de> - 2016-06-30 09:17 +0200
                                        Re: Can math.atan2 return INF? Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-30 00:17 -0700
                                    Re: Can math.atan2 return INF? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-30 18:06 +1200
                                      Re: Can math.atan2 return INF? Marko Rauhamaa <marko@pacujo.net> - 2016-06-30 09:32 +0300
                                  Re: Can math.atan2 return INF? Random832 <random832@fastmail.com> - 2016-06-29 09:55 -0400
                          Re: Can math.atan2 return INF? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-26 11:15 +1200
                            Re: Can math.atan2 return INF? MRAB <python@mrabarnett.plus.com> - 2016-06-26 00:31 +0100
                        Re: Can math.atan2 return INF? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-06-23 20:04 +0100
                  Re: Can math.atan2 return INF? pdorange@pas-de-pub-merci.mac.com (Pierre-Alain Dorange) - 2016-06-23 19:07 +0200
                Re: Can math.atan2 return INF? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-06-23 15:37 +0100

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#112167

FromPaul Rubin <no.email@nospam.invalid>
Date2016-07-31 20:41 -0700
Message-ID<87vazl5f5z.fsf@jester.gateway.pace.com>
In reply to#112166
Steven D'Aprano <steve@pearwood.info> writes:
> If Intuitionism influenced computer science, where is the evidence of this?
> Where are the Intuitionist computer scientists? 

Pretty much all of them, I thought.  E.g. programs in typed lambda
calculus amount to intuitionistic proofs of the propositions given in
the types (this is the Curry-Howard correspondence).  Languages like Coq
and Agda use the correspondence directly so you can state a
specification as a type, then prove the type as a theorem, and then
extract the proof as executable code which is certified to implement the
specification.  

The trendy area now is called "homotopy type theory", but I don't
understand even a tiny bit of it.

Intro to Coq: www.cis.upenn.edu/~bcpierce/sf/current/index.html

Proofs and types: www.paultaylor.eu/stable/Proofs+Types.html

Homotopy type theory: github.com/HoTT , homotopytypetheory.org

There's also a wiki at ncatlab.org which is in the intersection of logic
and CS, that develops a lot of this stuff.

> On the contrary, academic CS seems to have come from the Logicist
> school of thought

Do you mean formalist?  I thought that logicism was the idea that
mathematics could be derived from pure logic, and thus it went away when
Gӧdel's incompletness theorems appeared.

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#112168

FromRustom Mody <rustompmody@gmail.com>
Date2016-07-31 20:54 -0700
Message-ID<a5e2230a-e4b9-4146-9a77-2d5e86e76e3d@googlegroups.com>
In reply to#112167
On Monday, August 1, 2016 at 9:12:00 AM UTC+5:30, Paul Rubin wrote:
> Steven D'Aprano writes:
> > If Intuitionism influenced computer science, where is the evidence of this?
> > Where are the Intuitionist computer scientists? 
> 
> Pretty much all of them, I thought.  E.g. programs <details snipped>

Yeah…
Saying what does CS have to do with Intuitionism is like asking what
what does Carnot’s (theoretical) heat-engine have to do with Toyota

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#112169

FromRustom Mody <rustompmody@gmail.com>
Date2016-07-31 21:05 -0700
Message-ID<2909506b-ea11-481a-adf3-4ee6ed654c62@googlegroups.com>
In reply to#112166
On Monday, August 1, 2016 at 8:23:49 AM UTC+5:30, Steven D'Aprano wrote:
> On Sat, 30 Jul 2016 03:46 pm, Rustom Mody wrote:
> 
> > Lots of questions... I would guess rhetorical.
> 
> They weren't rhetorical.
> 
> You've made a lot of claims about the origins of computer science, and I've
> questioned some of your statements. Answers would be appreciated.
> 
> 
> > However under the assumption that they are genuine (or could be genuine
> > for others than you), I went back and checked.
> > I recollected that I started thinking along these lines — viz. that
> > philosophical disputes led to the genesis of computers — after reading an
> > essay by a certain Adam Siepel... which subsequently seems to have fallen
> > off the net
> > 
> > I tracked him down and re-posted his essay here:
> > http://blog.languager.org/2016/07/mechanism-romanticism-computers.html
> > 
> > Just to be clear — this is Dr. Adam Siepel's writing reposted with his
> > permission
> 
> 
> The essay is not awful, but I wouldn't shout its praises either. It looks to
> me like an undergraduate essay, taking a very narrow and rather naive view
> of the field. There's not a lot of references (only nine), which means the
> author is (in my opinion) excessively influenced by a small number of
> views, and I don't see any sign that he has even made a half-hearted
> attempt to seek out alternate views.
> 
> The author makes a claim:
> 
> "... Principia Mathematica, between 1910 and 1913, which in its attempt to
> place mathematics squarely in the domain of logic, represented the first
> new system of logic since Aristotle"
> 
> but doesn't give any justification for the claim. Why single out the
> Principia and ignore the works of the Stoics, Peter Abelard, William of
> Ockham, Augustus DeMorgan, Gottlob Frege and most especially George Boole
> dismissed?
> 
> I would think that if anyone truly deserved credit for creating a new system
> of logic, it should be Boole. But perhaps that's just a matter of opinion
> on where you draw the lines.
> 
> http://www.iep.utm.edu/prop-log/#H2
> 
> That's not really central to his argument, but it does suggest that his
> views are quite idiosyncratic. To my mind, that feels like someone claiming
> that Stephen Hawking is the first genuinely original physicist since
> Newton. Einstein? Schrödinger? Dirac? Never heard of 'em.
> 
> A rather large section of the essay is an irrelevant (and, I think,
> incorrect) digression about "Mechanists" and "Romantics", neither of which
> is really relevant to the philosophy of mathematics. He eventually mentions
> the Intuitionists, but I don't think he understands them. By linking them
> to the Romantics, he seems to think that the Intuitionist school of thought
> doesn't require mathematical proofs, or that they are satisfied with
> the "intuitively obvious truth" of axioms. But that's not what the
> Intuitionists were about:
> 
> https://en.wikipedia.org/wiki/Intuitionism
> 
> He mischaracterises and over-simplifies the argument over the foundations of
> mathematics:
> 
> https://en.wikipedia.org/wiki/Brouwer–Hilbert_controversy
> 
> with at least three separate groups involved (Logicists such as Russell,
> Formalists such as Hilbert, and Constructivists such as Poincaré -- four
> groups if you count Intuitionism separate from Constructionism). He
> exaggerates the death of the Logicist school of thought. It continues today
> with Second Order Logic.
> 
> And I wonder why you are taking this essay as supporting your position.
> According to this essay, the Intuitionists won in mathematics. And yet
> Turing and Von Neumann (two major pioneers of computing) were "Mechanists".
> If Intuitionism influenced computer science, where is the evidence of this?
> Where are the Intuitionist computer scientists? On the contrary, academic
> CS seems to have come from the Logicist school of thought, and practical
> computer engineering from "whatever works" school of thought.
> 
> None of this even *remotely* supports your assertions such as "[Turing]
> wishes to put the soul into the machine". Maybe he did. But this essay
> gives no reason to think so, or any reason to think that Turing's personal
> beliefs about souls is the slightest bit relevant to computer science.

My agreement vis-a-vis this essay is basically this:
Abstruse philosophical how-many-angels-on-a-pin type arguments amongst 
philosophers of math/logic across 19-20 century gave rise to Computers and Computer Science.

Some of the other detailed points you make, I agree with, eg.

1. There were more than 2 parties in the dispute
2. There is some arbitrary line-drawing there

(Un)fortunately arbitrary line-drawing is the name of the game everywhere:
Religion→Philosophy→History→Politics

<OT-Aside>
Right now as we speak there looks like a war — maybe world-war — in offing:
https://www.thenation.com/article/the-united-states-and-nato-are-preparing-for-a-major-war-with-russia/

Possibly democrat-engineered to discredit Trump:
https://www.thenation.com/article/neo-mccarthyism-and-olympic-politics-as-more-evidence-of-a-new-cold-war/

All starts with the disorder in the middle-east and a whole lot of arbitrary lines
drawn there
[Going backward in time]
- A line drawn in space called ‘Israel’
- Based on a line drawn in time called the ‘Exodus of Moses’
- Based on the supremely authoritative history-record called ‘The Bible’
  (or Torah depending on the speaker)

Leaving aside the first and the third, why specifically the Exodus as a definer?
Before Canaan they were in Egypt, so Israel=Egypt is equally legitimate
And before…before… they were in Eden.
Why not set Israel up in Eden?

May it just be the (in)convenient fact that knocking the Palestinians out of
their homes is easier than removing Mr. God from Eden?

Collapse of borders:
http://www.independent.co.uk/news/world/middle-east/isis-in-a-borderless-world-the-days-when-we-could-fight-foreign-wars-and-be-safe-at-home-may-be-long-a6741146.html
</OT-Aside>

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#112188

FromIan Kelly <ian.g.kelly@gmail.com>
Date2016-08-01 01:05 -0600
Message-ID<mailman.99.1470068689.6033.python-list@python.org>
In reply to#112169
On Sun, Jul 31, 2016 at 10:05 PM, Rustom Mody <rustompmody@gmail.com> wrote:
> All starts with the disorder in the middle-east and a whole lot of arbitrary lines
> drawn there
> [Going backward in time]
> - A line drawn in space called ‘Israel’
> - Based on a line drawn in time called the ‘Exodus of Moses’

I'm no expert but I believe that Zionism was based upon the idea of
Negation of the Diaspora, not Exodus.

> - Based on the supremely authoritative history-record called ‘The Bible’
>   (or Torah depending on the speaker)
>
> Leaving aside the first and the third, why specifically the Exodus as a definer?
> Before Canaan they were in Egypt, so Israel=Egypt is equally legitimate
> And before…before… they were in Eden.
> Why not set Israel up in Eden?

Since the Exodus story has it that the Israelites were slaves in Egypt
(despite the utter lack of archaeological evidence that they were ever
there en masse), placing Israel in Egypt would seem rather insulting.

> May it just be the (in)convenient fact that knocking the Palestinians out of
> their homes is easier than removing Mr. God from Eden?

Fun historical fact: the land of Palestine was so named by the Roman
Emperor Hadrian after he kicked the Jews out of their homes and forced
them to leave. The name was a Romanization of the ancient land of
Philistia, home of the Philistines, despite that they were long gone
by this point. So the entire existence of Palestine is basically one
big fat Roman middle finger to the Jews.

Not that any of this is meant to condone any of the violence in the Middle East.

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#111850

FromRustom Mody <rustompmody@gmail.com>
Date2016-07-24 19:48 -0700
Message-ID<9902c200-52d0-4e70-baa0-f721a4ed2ee5@googlegroups.com>
In reply to#110830
On Thursday, June 30, 2016 at 1:55:18 PM UTC+5:30, Steven D'Aprano wrote:
> On Thursday 30 June 2016 12:13, Rustom Mody wrote:
> 
> > In particular the question: "Are real numbers really real?" is where it
> > starts off... http://blog.languager.org/2015/03/cs-history-0.html
> 
> The pre-history of what later became computer science is very interesting, but 
> I fear that you are too focused on questions of "mysticism" and not enough on 
> what those people actually did and said.


I’ve been preparing material for some classes on Theory of Computation (ToC)

Starting from the premise that in a way Gödel is more primary to ToC than Turing

[And also been fan of Gödel-Escher-Bach from my college days]

And came across this proof (by Gödel!) that God exists <tickled> :
https://en.wikipedia.org/wiki/G%C3%B6del%27s_ontological_proof

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#110817

FromMarko Rauhamaa <marko@pacujo.net>
Date2016-06-30 09:24 +0300
Message-ID<878txnmbx0.fsf@elektro.pacujo.net>
In reply to#110794
Lawrence D’Oliveiro <lawrencedo99@gmail.com>:
> Every time somebody tries to point to an example of a “topic that is
> beyond the reach of science”, it seems to get knocked over eventually.

Of course, an experiment trumps theory, always.


Marko

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#110818

FromRustom Mody <rustompmody@gmail.com>
Date2016-06-29 23:29 -0700
Message-ID<3edf4137-d1f2-4198-8530-d57a7bc93621@googlegroups.com>
In reply to#110817
On Thursday, June 30, 2016 at 11:54:54 AM UTC+5:30, Marko Rauhamaa wrote:
> Lawrence D’Oliveiro :
> > Every time somebody tries to point to an example of a “topic that is
> > beyond the reach of science”, it seems to get knocked over eventually.
> 
> Of course, an experiment trumps theory, always.

The scholastics would call the question: "How many angels can dance on a pin"
a 'thought-experiment'

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#110838

FromDennis Lee Bieber <wlfraed@ix.netcom.com>
Date2016-06-30 07:47 -0400
Message-ID<mailman.135.1467287279.2358.python-list@python.org>
In reply to#110818
On Wed, 29 Jun 2016 23:29:41 -0700 (PDT), Rustom Mody
<rustompmody@gmail.com> declaimed the following:

>On Thursday, June 30, 2016 at 11:54:54 AM UTC+5:30, Marko Rauhamaa wrote:
>> Lawrence D’Oliveiro :
>> > Every time somebody tries to point to an example of a “topic that is
>> > beyond the reach of science”, it seems to get knocked over eventually.
>> 
>> Of course, an experiment trumps theory, always.
>
>The scholastics would call the question: "How many angels can dance on a pin"
>a 'thought-experiment'

	And before one can answer that, one must first answer:

Do angels even dance?
Are we talking a small-head sewing pin, or a large ball-headed map pin?
And is there a limit on how small an angel can compress itself (the old
testament angels tend to appear as large "beings", whilst the new testament
has them mostly human sized)
-- 
	Wulfraed                 Dennis Lee Bieber         AF6VN
    wlfraed@ix.netcom.com    HTTP://wlfraed.home.netcom.com/

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#110849

Fromalister <alister.ware@ntlworld.com>
Date2016-06-30 14:54 +0000
Message-ID<joadz.1241015$UD7.800962@fx39.am4>
In reply to#110817
On Thu, 30 Jun 2016 09:24:43 +0300, Marko Rauhamaa wrote:

> Lawrence D’Oliveiro <lawrencedo99@gmail.com>:
>> Every time somebody tries to point to an example of a “topic that is
>> beyond the reach of science”, it seems to get knocked over eventually.
> 
> Of course, an experiment trumps theory, always.
> 
> 
> Marko

in theory there is no difference between theory and practice
in practice there is 



-- 
Q:	What is purple and commutes?
A:	An Abelian grape.

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#110820

FromPaul Rubin <no.email@nospam.invalid>
Date2016-06-29 23:57 -0700
Message-ID<87mvm3maep.fsf@nightsong.com>
In reply to#110794
> Every time somebody tries to point to an example of a “topic that is
> beyond the reach of science”, it seems to get knocked over eventually.

Generate a sequence of "random" bits from your favorite physical source
(radioactive decay, quantum entanglement, or whatever).  Is the sequence
really algorithmically random (like in Kolmogorov randomness)?  This is
scientifically unknowable.  To check the randomness you have to solve
the halting problem.

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#110823

FromLawrence D’Oliveiro <lawrencedo99@gmail.com>
Date2016-06-30 00:16 -0700
Message-ID<bf80c4ec-9167-4d02-8fdb-893b7912f17f@googlegroups.com>
In reply to#110820
On Thursday, June 30, 2016 at 6:57:41 PM UTC+12, Paul Rubin wrote:

>> Every time somebody tries to point to an example of a “topic that is
>> beyond the reach of science”, it seems to get knocked over eventually.
> 
> Generate a sequence of "random" bits from your favorite physical source
> (radioactive decay, quantum entanglement, or whatever).  Is the sequence
> really algorithmically random (like in Kolmogorov randomness)?  This is
> scientifically unknowable.

The definition of “random” is “unknowable”. So all you are stating is a tautology.

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#110826

FromPaul Rubin <no.email@nospam.invalid>
Date2016-06-30 00:32 -0700
Message-ID<87inwrm8ro.fsf@nightsong.com>
In reply to#110823
Lawrence D’Oliveiro <lawrencedo99@gmail.com> writes:
> The definition of “random” is “unknowable”. So all you are stating is
> a tautology.

What?  No.  You read a bunch of bits out of the device and you want to
know whether they are Kolmogorov-random (you can look up what that means
if you're not familiar with it).  Quantum theory says they are, but if
it is true, there is no scientific way to confirm it.

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#110827

FromLawrence D’Oliveiro <lawrencedo99@gmail.com>
Date2016-06-30 00:39 -0700
Message-ID<fa17e724-ecfd-418c-8593-251ab9112ba6@googlegroups.com>
In reply to#110826
On Thursday, June 30, 2016 at 7:32:55 PM UTC+12, Paul Rubin wrote:
> Lawrence D’Oliveiro writes:
>> The definition of “random” is “unknowable”. So all you are stating is
>> a tautology.
> 
> What?  No.  You read a bunch of bits out of the device and you want to
> know whether they are Kolmogorov-random (you can look up what that means
> if you're not familiar with it).  Quantum theory says they are, but if
> it is true, there is no scientific way to confirm it.

Randomness is not something you can ever prove. Which is why it is the weak point of all encryption algorithms.

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#110831

FromSteven D'Aprano <steve+comp.lang.python@pearwood.info>
Date2016-06-30 18:27 +1000
Message-ID<5774d7ee$0$1617$c3e8da3$5496439d@news.astraweb.com>
In reply to#110823
On Thursday 30 June 2016 17:16, Lawrence D’Oliveiro wrote:

> The definition of “random” is “unknowable”.


It really isn't.

What Julius Caesar had for breakfast on the day after his 15th birthday is 
unknowable.

To the best of our knowledge, the collapse of a quantum wave function is 
random.


-- 
Steve

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#110822

FromAndreas Röhler <andreas.roehler@online.de>
Date2016-06-30 09:17 +0200
Message-ID<mailman.126.1467270804.2358.python-list@python.org>
In reply to#110794

On 30.06.2016 03:33, Lawrence D’Oliveiro wrote:

> So you see, like it or not, we are drawn to the conclusion that there *was* indeed something before our particular Big Bang.

That's linear like the Big Bang theorie. What about assuming something 
beyond our notion of time and space, unknown still?

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#110824

FromLawrence D’Oliveiro <lawrencedo99@gmail.com>
Date2016-06-30 00:17 -0700
Message-ID<11c11893-9d26-420d-a986-34fce70acb07@googlegroups.com>
In reply to#110822
On Thursday, June 30, 2016 at 7:13:36 PM UTC+12, Andreas Röhler wrote:
> On 30.06.2016 03:33, Lawrence D’Oliveiro wrote:
> 
>> So you see, like it or not, we are drawn to the conclusion that there
>> *was* indeed something before our particular Big Bang.
> 
> That's linear like the Big Bang theorie. What about assuming something 
> beyond our notion of time and space, unknown still?

M-theory? Branes? Multiverse? All part of the current scientific intellectual landscape.

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#110814

FromGregory Ewing <greg.ewing@canterbury.ac.nz>
Date2016-06-30 18:06 +1200
Message-ID<dtjr75Fsva0U1@mid.individual.net>
In reply to#110770
Marko Rauhamaa wrote:
> By the time the event horizon hits Tim at the speed of light, Tim will
> have received all of our Universe's signals at an ever accelerating
> frequency and increasing power. He will have seen the End of the World
> before leaving it.

I don't think that's right. From the point of view of an
infalling observer, nothing particularly special happens
at the event horizon. Being able to see into the future
would count as rather special, I would have thought.

-- 
Greg

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#110819

FromMarko Rauhamaa <marko@pacujo.net>
Date2016-06-30 09:32 +0300
Message-ID<874m8bmbk1.fsf@elektro.pacujo.net>
In reply to#110814
Gregory Ewing <greg.ewing@canterbury.ac.nz>:

> Marko Rauhamaa wrote:
>> By the time the event horizon hits Tim at the speed of light, Tim will
>> have received all of our Universe's signals at an ever accelerating
>> frequency and increasing power. He will have seen the End of the World
>> before leaving it.
>
> I don't think that's right. From the point of view of an infalling
> observer, nothing particularly special happens at the event horizon.
> Being able to see into the future would count as rather special, I
> would have thought.

Yeah, you have a point:

   IF you could stand still, you would see light from behind as
   blue-shifted, precisely the flip side of gravitational redshifting
   for distant observers. However, if you were traveling on a free-fall
   geodesic, you would see no blueshift from light directly behind,
   because you and it would be in the same inertial reference frame.

   <URL: http://physics.stackexchange.com/questions/26185/what-will-th
   e-universe-look-like-for-anyone-falling-into-a-black-hole>


Marko

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#110780

FromRandom832 <random832@fastmail.com>
Date2016-06-29 09:55 -0400
Message-ID<mailman.109.1467208540.2358.python-list@python.org>
In reply to#110762
On Wed, Jun 29, 2016, at 05:35, Steven D'Aprano wrote:
> Although their perspectives are very different, neither is "more
> right" than the other.

I think usually the idea that there are "no privileged frames of
reference" doesn't go so far as to include ones from which it is
impossible to send information to the rest of. When it's impossible for
observations to be transmitted back to Earth (or to anywhere else),
you've crossed a line from science to philosophy.

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#110504

FromGregory Ewing <greg.ewing@canterbury.ac.nz>
Date2016-06-26 11:15 +1200
Message-ID<dt8hk7FkgprU1@mid.individual.net>
In reply to#110431
Steven D'Aprano wrote:
> China has just announced a new supercomputer that is so fast it can run an
> infinite loop in 3.7 seconds.

They're lying. It has to be NaN seconds.

-- 
Greg

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