Computronium == unobtainium

Paul Raven @ 09-03-2011

Via Next Big Future, Doctor Suzanne Gildert of the excellently-named Physics & Cake blog takes apart the [science fictional / Singularitarian] concept of computronium, and does a pretty good job of explaining why it probably isn’t possible:

… as we see, atoms are already very busy computing things. In fact, you can think of the Universe as computing itself. So in a way, matter is already computronium, because it is very efficiently computing itself. [This reminds me of Rudy Rucker’s theories about gnarl and universe-as-computing-substrate – PGR] But we don’t really want matter to do just that. We want it to compute the things that WE care about (like the probability of a particular stock going up in value in the next few days). But in order to make the Universe compute the things that we care about, we find that there is an overhead – a price to pay for making matter do something different from what it is meant to do. Or, to give a complementary way of thinking about this: The closer your computation is to what the original piece of matter would do naturally, the more efficient it will be.

So in conclusion, we find that we always have to cajole matter into computing the things we care about. We must invest extra resources and energy into the computation. We find that the best way to arranging computing elements depends upon what we want them to do. There is no magic ‘arrangement of matter’ which is all things to all people, no fabled ‘computronium’. We have to configure the matter in different ways to do different tasks, and the most efficient configuration varies vastly from task to task.

If it’s not too meta a get-out clause, perhaps we could develop some sort of nanotech system for reconfiguring computational substrate matter into the most appropriate arrangement for the task at hand? Talk about an abstraction layer… 🙂

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4 Responses to “Computronium == unobtainium”

  1. Charlie Stross says:

    Ahem: I think she got the definition of computronium very wrong indeed. (It’s not matter where every single atom performs computation; it’s the densest computing system that can be built using matter.) Then she proceeds to analyse it purely in terms of classical physics without for example noting techniques like reversible computing (https://secure.wikimedia.org/wikipedia/en/wiki/Reversible_computing) for working around the thermodynamic limits, or quantum computing. She seems to be unfamiliar with the work of Seth Lloyd, who has already stomped around the area she’s tackling and come to rather different conclusions. Then she runs off the rails completely into a forest of woo with her discussion of the inadequacies of Turing machines.

    Basically she’s demolishing a straw man of her own construction. Inelegantly.

  2. Rick York says:

    Well, we may not have programmable atoms but, how about molecules?

    http://www.sciencedaily.com/releases/2011/03/110309113036.htm

  3. Wintermute says:

    A straw man is good to beat.

  4. Khannea Suntzu says:

    Computronium is a goal. It won’t be reached but there is a LOT of space between current chips and optimal arrangement of available minerals.

    I propose a lesser scale of computronium – “computronide” – a to some degree self-organizing nanoid-driven computational substrate that is available upon science and technology, safety constrains, energy constraints and material constraints. And supporting infrastructure.

    In metallic asteroids there will, a century from now, certain types of optimal computronides. This material will operate in cold states, with limited available metals, lots of volatile components and fair to modest state of technology and support infrastructure.

    Mercury will have breathtaking energy gradients, lots of heavy metals, may have a somewhat iffy state of science and technology (its twice as hard to fly to Mercury as it is to Saturn). So Mercurial “servers” will have rather ‘industrial’ computronite processes.

    My best bet for computronite for a long time, in terms of energy gradient (tectonic plates, atmospheric cooling), available support technology and materials remains, for a long time Terrestrial Computronite.

    The pressure of evolution will of course be towards a halo of industrial/computational particles orbiting the sun at a prudent range. I’d christen this concept of an emerging Dyson sphere a strossium halo, or “accelerandium”, but its an old idea clearly. I can see it start forming as a discrete metallic entity just inside the terrestrial orbit in a century or two, maybe less.

    It’ll start by eating up Mercury and all the inner asteroids. Lets hope it’ll be lots of O’Neill habitats, because the alternative is too scary to contemplate.