X-Message-Number: 11735 From: Thomas Donaldson <> Subject: answers to various, with comments for Bob Ettinger at the end Date: Wed, 12 May 1999 23:12:09 +1000 (EST) Hi everyone! Daniel Crevier asks why I insist on parallel computers. My reasons are simple: any computer that must deal with the real world will have to be quite fast, faster than any existing or foreseen sequential processor. It is just not enough to be a Turing machine: the data will come much to fast for a classical Turing machine, and too fast for a sequential machine. As a very simple example, consider vision. I will note that this is a function which requires either outright parallel computing, or highly specialized processors which act in parallel while the rest of the computer plods along sequentially. To operate in the real world speed on some things is essential. At one point one person on Cryonet pointed out the merits of quantum computing here. If we can really get quantum computing going it will be a good thing; however since quantum computers work on multiple possibilities simultaneously, they too count as parallel. As for the complexity of the computer compared to the complexity of the world, the problem with a virtual person living in a virtual world is that so far is it is more complex than the world that complexity isn't exercised at all. As you well know, when presented with no stimuli at all, the normal human reaction is either to produce illusions or to go to sleep. And even the production of illusions does not last forever: we need data to think on and data to stimulate us constantly. And so the complex virtual person behaves just like a simple virtual person, and is no more alive than if that complexity never existed. You also made some distinctions: a virtual person would have to have particular circuits (not fully specified) to be conscious. (I gave the PC example to force you to consider just what was needed). But consciousness cannot exist in total isolation; it is always consciousness of SOMETHING. And without anything which matches the complexity of your brain, you will cease to be conscious at all. (Imagine the effect if the only thing you could see or do was to look at a blank white wall. Sure, if someone rescued you after a few hours, you could revive to full consciousness. But years of blank white wall would kill your ability to sense anything else, and so kill you). Put briefly, we cannot separate consciousness from its subject, and cannot have a complex virtual person living in a simple virtual world. That is why the complexity of the world becomes so important; and also given the speed with which things happen in the real world, why parallel computing would be necessary. And for other commentators: As for the consciousness of animals, I will point out that neuroscientists have considered this issue. It is NOT just a matter of philosophy and should not be considered as such. And in those terms, many birds and mammals have brain structures similar enough to our own that we would really be straining our ideas to argue that they were not conscious. Whether or not they could communicate what they were conscious of is a different question and should be seen as such; and some features might stand out strongly in what they perceived while for us those features were almost absent. (Rats have a highly developed sense of smell --- their world must be much more a matter of many different odors than ours). And for Bob Ettinger: You have several times suggested that brains may have features which make them impossible to emulate by other kinds of devices. One quite major difference which neuroscientists have found is that brains are constantly rewiring themselves on microscopic scales; that rewiring is part of the acquisition of true long term memory. And so not even any existing neural net can really emulate the workings of a brain. However I am not convinced that we could not build a device which would also have that feature (though it would most certainly work differently from any existing computer). For that matter, it's not certain that such features are required for consciousness --- though we might be able to do some computer tests which might through light on that issue (a computer behaving as it could rewire itself could only do so for a short time, but that might be enough). Best and long long life to all Thomas Donaldson PS: About the worth of this topic: some cryonicists, as I understand, really do think that they will be brought back in computers. We are discussing this possibility and its plausibility. Those who already accept that they will NOT be brought back in computers are welcome when they choose not to pay attention to this discussion. It's not meant for them anyway. And yes, I personally am very interested in work to improve our suspension methods and ideally prevent all damage to our brains. I'm happy to give money to any agency which plausibly promises to work on that problem. But cryonics raises many more questions than the bare one of survival, though survival remains primary. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=11735