[ExI] Meat v. Machine

Anders Sandberg anders at aleph.se
Thu Dec 30 16:33:21 UTC 2010

John Clark wrote:
> Right now virtually all photons of electromagnetic energy created in 
> the universe are radiated uselessly away into infinite space, that's 
> not very good evidence of a cosmic civilization deeply concerned with 
> the conservation of resources. If they were thinking really long term 
> they'd convert much of the mass in the universe into brains and the 
> remaining mass into the smallest red dwarf stars that can still 
> produce fusion, with Dyson spheres constructed around them to power 
> the computers.
This was my previous position too, and it furnished a pretty good 
argument that there were either no aliens about, or they had 
"transcended our plane of existence". However, in a discussion with 
Milan Circovic I realized that letting stars shine only lose you ~1% of 
their mass-energy. If you are really advanced and long-term, you will 
burn the matter in black holes achieving ~50% efficiency in a very cold 
future where every Joule is worth many more bits. So if stopping stars 
takes a significant effort (which seems likely, you have to star lift 
them and then redistribute sizeable chunks of matter), then it might not 
be worth it.

I guess I should do a proper economic analysis of this. But it seems 
that if you have a huge time horizon then the current waste might not 
matter much, unless it least to a lot of lost gas.

The reason to wait is the Brillouin inequality: you get 1/kTln(2) bits 
of information out of a Joule of energy, so if you wait until the 
universe is twice as cold you get twice as much computation. Eventually 
(if current cosmological models are right) the temperature will reach a 
steady level of ~10^-19 K due to de Sitter horizon radiation and there 
is no point in waiting any more. But that means matter gets 10^19 times 
more valuable if you wait!

It seems likely that Jupiter brains will have a pretty good theory of 
the universe after a mere million years or so. It is not clear to me 
that there is any reason to think that they will get a huge physics 
surprise if they spend another billion years on the problem. Instead 
they might decide to spend their calculations on whatever they consider 
valuable and not just instrumentally useful.

Anders Sandberg,
Future of Humanity Institute
Philosophy Faculty of Oxford University 

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