Re: Cosmology and Boltzmann brains

2008-06-19 Thread Bruno Marchal
On 19 Jun 2008, at 02:51, Brent Meeker wrote: Günther Greindl wrote: Brent, scientific theory. Occams razor is a vague desiderata. You can justify almost anything by choosing your definition of complex, e.g. theists say, God did it. is the simplest possible theory. no you

Re: Cosmology and Boltzmann brains

2008-06-18 Thread Brent Meeker
Russell Standish wrote: On Tue, Jun 17, 2008 at 09:24:21PM -0700, Brent Meeker wrote: scientific theories (doing so by definition). The reason it is rejected is because of the arbitrary nature of the date makes it a more complex theory (in the Occam's razor sense). And it is not

Re: Cosmology and Boltzmann brains

2008-06-18 Thread Günther Greindl
Brent, scientific theory. Occams razor is a vague desiderata. You can justify almost anything by choosing your definition of complex, e.g. theists say, God did it. is the simplest possible theory. no you can't: http://www.overcomingbias.com/2007/09/occams-razor.html most relevant quote

Re: Cosmology and Boltzmann brains

2008-06-18 Thread Brent Meeker
Günther Greindl wrote: Brent, scientific theory. Occams razor is a vague desiderata. You can justify almost anything by choosing your definition of complex, e.g. theists say, God did it. is the simplest possible theory. no you can't:

Re: Cosmology and Boltzmann brains

2008-06-17 Thread Bruno Marchal
Hi Greg, Thanks very much, everyone, for an interesting discussion, and thanks for your patience towards someone who hasn't read your previous debates on these issues. You are welcome Greg. I hope to find time to follow up all the links people gave. Russell, that link to the

Re: Cosmology and Boltzmann brains

2008-06-17 Thread Brent Meeker
Russell Standish wrote: On Sun, Jun 15, 2008 at 01:40:09AM -0700, Greg Egan wrote: ... But we do this all the time. Why is it we reject crackpot claims that the world will end on such and such a date for instance? We reject those claims because they flow from theories that we reason should

Re: Cosmology and Boltzmann brains

2008-06-16 Thread Russell Standish
Sorry about that. It seems one needs the stuff after the domain - try http://everythingwiki.gcn.cx/wiki/index.php?title=Main_Page Cheers On Sun, Jun 15, 2008 at 07:34:39PM -0700, Greg Egan wrote: Thanks very much, everyone, for an interesting discussion, and thanks for your patience

Re: Cosmology and Boltzmann brains

2008-06-15 Thread Greg Egan
On Jun 15, 1:27 pm, Russell Standish [EMAIL PROTECTED] wrote: What sparked our/my interest is that you seemed to have interesting argument against the use of anthropic reasoning. I'm certainly not arguing against *all* anthropic reasoning; every argument needs to be examined on a case by case

Re: Cosmology and Boltzmann brains

2008-06-15 Thread Bruno Marchal
Hi Greg, On 15 Jun 2008, at 10:40, Greg Egan wrote: My attributes (eg height, weight and so on) are all drawn from distributions of such attributes. Why not some hypothetical property like observer class as set up in this toy problem? Why is your height and weight drawn from a certain

Re: Cosmology and Boltzmann brains

2008-06-15 Thread Russell Standish
On Sun, Jun 15, 2008 at 01:40:09AM -0700, Greg Egan wrote: My attributes (eg height, weight and so on) are all drawn from distributions of such attributes. Why not some hypothetical property like observer class as set up in this toy problem? Why is your height and weight drawn from a

Re: Cosmology and Boltzmann brains

2008-06-15 Thread Greg Egan
Thanks very much, everyone, for an interesting discussion, and thanks for your patience towards someone who hasn't read your previous debates on these issues. I hope to find time to follow up all the links people gave. Russell, that link to the Everything Wiki currently gives a 403.

Re: Cosmology and Boltzmann brains

2008-06-14 Thread Stathis Papaioannou
2008/6/14 Greg Egan [EMAIL PROTECTED]: The context in which I was discussing this at the N-Category Café is the claim by some cosmologists that we ought to favour A-type cosmological theories in which class 2 observers like us, with a clear Darwinian history, will not be outnumbered (over the

Re: Cosmology and Boltzmann brains

2008-06-14 Thread Russell Standish
Hi Greg, and welcome to the list. Your ears must be burning - you have often been talked about here, always in a good light! On Fri, Jun 13, 2008 at 09:28:07PM -0700, Greg Egan wrote: On Jun 13, 9:25 am, Russell Standish [EMAIL PROTECTED] wrote: I'm not sure his application of Bayes is

Re: Cosmology and Boltzmann brains

2008-06-14 Thread Greg Egan
Hi Russell, thanks very much for your reply. It's possible that I'm arguing at cross-purposes here, because I gather that the whole reason for this list is to discuss models of the universe that are very different from standard cosmology, but I hope you won't mind if I pursue a defence of my

Re: Cosmology and Boltzmann brains

2008-06-13 Thread Greg Egan
On Jun 13, 9:25 am, Russell Standish [EMAIL PROTECTED] wrote: I'm not sure his application of Bayes is correct. Given the facts of his hypothetical scenario, and writing e=10^{-4050}   p(1|A) = e   p(2|A) = 1-e   p(1|B) = 1-e   p(2|B) = e This is my translation of: Now suppose that

Re: Cosmology and Boltzmann brains

2008-06-12 Thread Stathis Papaioannou
2008/6/13 Günther Greindl [EMAIL PROTECTED]: Hi all, someone on another list alerted me to this post, there is a very interesting discussion going on on that blog related to Observer Moments: http://golem.ph.utexas.edu/category/2008/06/urban_myths_in_contemporary_co.html Is the ensemble of

Re: Cosmology and Boltzmann brains

2008-06-12 Thread Russell Standish
On Fri, Jun 13, 2008 at 10:28:28AM +1000, Stathis Papaioannou wrote: Is the ensemble of observer moments generated by the postulated BB's different from the ensemble of all possible observer moments? I don't see how it could be different. AFAICT BBs are nothing other than the infamous

Re: Cosmology and Boltzmann brains

2008-06-12 Thread Russell Standish
On Thu, Jun 12, 2008 at 11:43:26PM +0200, Günther Greindl wrote: Hi all, someone on another list alerted me to this post, there is a very interesting discussion going on on that blog related to Observer Moments: