[ExI] Unsolved problems

[scerir]

Keith Henson
> So a large chunk of computronium, if it is to be 
> of "one mind" has to think slower than a smaller piece.

The concept of computability has to do with matter
but also with time and space-time. There are models
of hypercomputation and non-Turing computation.

http://ftp.math-inst.hu/pub/algebraic-logic/beyondturing.pdf
http://www.hypercomputation.net/download/1996a_hogarth.pdf

On the other side Zeilinger demonstrated the feasibility 
of quantum communication and computation in space, 
involving satellites. 

http://arxiv.org/abs/0803.1871
http://arxiv.org/abs/quant-ph/0607182
http://arxiv.org/abs/quant-ph/0308174
http://arxiv.org/abs/quant-ph/0305105
http://arxiv.org/abs/quant-ph/0109022

In other words, there are chances/hopes that Nature 
is more powerful than actual or near-future computation.