Comments on: Limits to Physics Insight http://www.overcomingbias.com/2008/03/limits-to-physi.html Overcoming Bias is economist Robin Hanson’s blog, on honesty, signaling, disagreement, forecasting, and the far future. Sun, 14 Mar 2010 19:40:08 -0400 http://wordpress.org/?v=2.8.5 hourly 1 By: Robin Hanson http://www.overcomingbias.com/2008/03/limits-to-physi.html#comment-407229 Robin Hanson Thu, 13 Mar 2008 11:15:00 +0000 http://prod.ob.trike.com.au/2008/03/limits-to-physics-insight.html#comment-407229 My guess is also that no aliens is the most likely scenario, but the value of finding them seems so huge as to justify looking even if the chances are low. I'm not endorsing any strong claim of the form we can prove that our descendants couldn't know - just that this is a nice clear plausible example of something they may well not know. Assistant, we bear a great deal of relation to any creature that exists in the same physical universe as ours. My guess is also that no aliens is the most likely scenario, but the value of finding them seems so huge as to justify looking even if the chances are low. I’m not endorsing any strong claim of the form we can prove that our descendants couldn’t know – just that this is a nice clear plausible example of something they may well not know.

Assistant, we bear a great deal of relation to any creature that exists in the same physical universe as ours.

]]> By: Pseudonymous http://www.overcomingbias.com/2008/03/limits-to-physi.html#comment-407228 Pseudonymous Wed, 12 Mar 2008 20:55:04 +0000 http://prod.ob.trike.com.au/2008/03/limits-to-physics-insight.html#comment-407228 <i>Our successors, whoever and wherever they are, may have no way of finding out about the Big Bang and the expanding universe, according to one of the more depressing scientific papers I have ever read.</i> Surely this is a matter of history rather than physics. And we have always known that historical knowledge can be lost. Our successors, whoever and wherever they are, may have no way of finding out about the Big Bang and the expanding universe, according to one of the more depressing scientific papers I have ever read.

Surely this is a matter of history rather than physics. And we have always known that historical knowledge can be lost.

]]> By: Meaux http://www.overcomingbias.com/2008/03/limits-to-physi.html#comment-407227 Meaux Tue, 11 Mar 2008 23:57:05 +0000 http://prod.ob.trike.com.au/2008/03/limits-to-physics-insight.html#comment-407227 100 Billion years, eh? Makes me feel, well, suicidal. Meaux 100 Billion years, eh?

Makes me feel, well, suicidal.

Meaux

]]> By: Assistant Village Idiot http://www.overcomingbias.com/2008/03/limits-to-physi.html#comment-407226 Assistant Village Idiot Tue, 11 Mar 2008 22:26:22 +0000 http://prod.ob.trike.com.au/2008/03/limits-to-physics-insight.html#comment-407226 The idea that creatures descended from us even a thousand years hence, never mind billions of years, bear any relation to us whatsoever strikes me as fanciful imagining. Technological change accelerates - there is simply nothing to contemplate about those entities that has the remotest chance of being true. It smells like a search-for-god-anywhere-else exercise. And to think we disdain medievals for debating how many angels can dance on the head of a pin! We at least know what a pin is, and a dance is, and have some general idea what an angel is thought to be. There is no epistemology in this, just stoner science-fiction. The idea that creatures descended from us even a thousand years hence, never mind billions of years, bear any relation to us whatsoever strikes me as fanciful imagining. Technological change accelerates – there is simply nothing to contemplate about those entities that has the remotest chance of being true.

It smells like a search-for-god-anywhere-else exercise. And to think we disdain medievals for debating how many angels can dance on the head of a pin! We at least know what a pin is, and a dance is, and have some general idea what an angel is thought to be.

There is no epistemology in this, just stoner science-fiction.

]]> By: Maggie's Farm http://www.overcomingbias.com/2008/03/limits-to-physi.html#comment-407230 Maggie's Farm Tue, 11 Mar 2008 22:09:05 +0000 http://prod.ob.trike.com.au/2008/03/limits-to-physics-insight.html#comment-407230 <strong>A lesson in humility</strong> In a little while, our universe will look different. A lesson in humility

In a little while, our universe will look different.

]]> By: Sebastian Hagen http://www.overcomingbias.com/2008/03/limits-to-physi.html#comment-407225 Sebastian Hagen Tue, 11 Mar 2008 21:34:42 +0000 http://prod.ob.trike.com.au/2008/03/limits-to-physics-insight.html#comment-407225 Nick Tarleton: It's a possibility, but it strikes me as very unlikely. Note that: 1) A single civilization that decides to do otherwise would break this. 2) This doesn't need to be a decision of the whole civilization; if an arbitrary subset with access to sufficient technology decides to do this, they could just head out some way into space, and start converting matter once they're far enough away that their growth curve will hand them a tactical advantage over the main civilization before the authorities notice. To prevent this, the civlization would either have to be a lot more homogenous than present-day humanity, or feature <i>very</i> effective controls against this sort of thing on their citizens. 3) Similarly, in the absence of free storage+computation (case 4 in my previous post) a significant subset of UFAI designs (paperclip optimizers, wingnut optimizers, red stapler optimizers, ...) is likely to turn into matter-gobblers. 4) Natural selection has a tendency to produce organisms that try to maximize the resources available to them/other organisms with a similar genome (like their offspring). 5) For very many possible goals, how well you can implement them will depend on how much storage space and cputime you can get your hands on. In our universe, cputime sems to be limited largely by the laws of thermodynamics. In many ways, the <i>conservative</i> thing to do is to turn off any accessible stars as early as possible, and take your time to think about what to do with the resources afterwards. If you don't do this, they'll continue to burn through order you could have put to much better use. Greg Egan's <a href="http://en.wikipedia.org/wiki/Diaspora_%28novel%29" rel="nofollow">Dispora</a> features a multiverse with a number of alien civilizations, all of which deliberately (and at least in the case of human-derived civilizations, by <i>individual</i> choice) avoid gobbling up lots of resources. I consider that one of the least realistic aspects of the book. Nick Tarleton: It’s a possibility, but it strikes me as very unlikely. Note that:
1) A single civilization that decides to do otherwise would break this.
2) This doesn’t need to be a decision of the whole civilization; if an arbitrary subset with access to sufficient technology decides to do this, they could just head out some way into space, and start converting matter once they’re far enough away that their growth curve will hand them a tactical advantage over the main civilization before the authorities notice.
To prevent this, the civlization would either have to be a lot more homogenous than present-day humanity, or feature very effective controls against this sort of thing on their citizens.
3) Similarly, in the absence of free storage+computation (case 4 in my previous post) a significant subset of UFAI designs (paperclip optimizers, wingnut optimizers, red stapler optimizers, …) is likely to turn into matter-gobblers.
4) Natural selection has a tendency to produce organisms that try to maximize the resources available to them/other organisms with a similar genome (like their offspring).
5) For very many possible goals, how well you can implement them will depend on how much storage space and cputime you can get your hands on. In our universe, cputime sems to be limited largely by the laws of thermodynamics.
In many ways, the conservative thing to do is to turn off any accessible stars as early as possible, and take your time to think about what to do with the resources afterwards. If you don’t do this, they’ll continue to burn through order you could have put to much better use.

Greg Egan’s Dispora features a multiverse with a number of alien civilizations, all of which deliberately (and at least in the case of human-derived civilizations, by individual choice) avoid gobbling up lots of resources. I consider that one of the least realistic aspects of the book.

]]> By: Nato Welch http://www.overcomingbias.com/2008/03/limits-to-physi.html#comment-407224 Nato Welch Tue, 11 Mar 2008 21:23:08 +0000 http://prod.ob.trike.com.au/2008/03/limits-to-physics-insight.html#comment-407224 Science, as we have known and practiced it, is only a few thousand years old. Doesn't it seem a little premature to speculate about how "they" will practice it millions of years hence, if at all? As for the problem of long-term archiving, I defer to Linus Torvalds: "Only wimps use tape backup: _real_ men just upload their important stuff on ftp, and let the rest of the world mirror it ;)" Science, as we have known and practiced it, is only a few thousand years old. Doesn’t it seem a little premature to speculate about how “they” will practice it millions of years hence, if at all?

As for the problem of long-term archiving, I defer to Linus Torvalds:
“Only wimps use tape backup: _real_ men just upload their important stuff
on ftp, and let the rest of the world mirror it ;) ”

]]> By: steven http://www.overcomingbias.com/2008/03/limits-to-physi.html#comment-407223 steven Tue, 11 Mar 2008 18:33:27 +0000 http://prod.ob.trike.com.au/2008/03/limits-to-physics-insight.html#comment-407223 I'm very skeptical of this sort of claim -- you have no idea what future civilizations can't know. There could be all sorts of ways to deduce a big bang given more knowledge. What about just the second law of thermodynamics alone? I’m very skeptical of this sort of claim — you have no idea what future civilizations can’t know. There could be all sorts of ways to deduce a big bang given more knowledge. What about just the second law of thermodynamics alone?

]]> By: George Weinberg http://www.overcomingbias.com/2008/03/limits-to-physi.html#comment-407222 George Weinberg Tue, 11 Mar 2008 17:50:27 +0000 http://prod.ob.trike.com.au/2008/03/limits-to-physics-insight.html#comment-407222 <i>, there may well be physics that we can only learn via records saved by ancient aliens</i> Well, no there can't, because alleged records from bug-eyed monsters billions of years in the past are not the same as actual observations. Anything that could be learned in this way would be mythology, not physics. , there may well be physics that we can only learn via records saved by ancient aliens

Well, no there can’t, because alleged records from bug-eyed monsters billions of years in the past are not the same as actual observations. Anything that could be learned in this way would be mythology, not physics.

]]> By: Nick Tarleton http://www.overcomingbias.com/2008/03/limits-to-physi.html#comment-407221 Nick Tarleton Tue, 11 Mar 2008 17:22:55 +0000 http://prod.ob.trike.com.au/2008/03/limits-to-physics-insight.html#comment-407221 4.5) They existed, and the ones in our past light cone that didn't wipe themselves out decided for whatever reason not to acquire a lot of computronium (and there are few enough of them that all of them chose similarly). Though I also think (1) is most likely. 4.5) They existed, and the ones in our past light cone that didn’t wipe themselves out decided for whatever reason not to acquire a lot of computronium (and there are few enough of them that all of them chose similarly).

Though I also think (1) is most likely.

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