X-Message-Number: 21194 Date: Mon, 17 Feb 2003 08:15:37 -0500 From: Thomas Donaldson <> Subject: CryoNet #21179 - #21192 For James Swayze: I began my discussion of respirocytes by pointing out that that they did not now EXIST. This makes their evaluation in comparison with present ideas for similar systems to be quite difficult, since after all dreams always turn out better than reality. Nor do I think that any amount of previous calculation will solve that problem. Your note raises lots of issues, more than I can go through briefly. I would be happy to BUY Freitas's book, if I knew where to go to do so. However I will begin with a basic issue. Evolution has NOT CEASED. It simply bears on different traits than those it bore on before. If I choose to make a modification of myself, and this modification doesn't turn out as well as I'd hoped, that is evolution in action. For that matter, external events will also affect our evolution, just as they always have. It's just that their effects will be mixed up much more with our choices in responding to them. Your advantage to respirocytes, when examined, looks quite weird. OK, so now we have this guy with artificial blood which does not require oxygen as often as we do, and HE SUFFERS A HEART ATTACK? Now wait a minute here! You seem to be proposing that we will someday have this marvellous nanotechnology, complete with respirocytes, but still suffer from HEART ATTACKS? No doubt our respirocytes will also protect our brains from strokes, etc etc. I hope you understand just how weird such a world would be. At one time I wrote an article for ANALOG pointing out all the stories full of interstellar flight, teleportation, etc etc etc, in which the level of medicine remained that of the early 20th Century. That is ABSURD. (As a side issue, a heart attack occurs when one area in our heart muscle becomes deprived of blood flow. A stroke occurs when one area in our brain becomes deprived of blood flow. So does this mean that the respirocytes in these areas turn themselves off while all the others continue working?) In real life, we do not try to protect ourselves constantly against all kinds of natural or human threats regardless of the cost of doing so. Respirocytes would not only have to have the ability to protect us, but also cause us even fewer problems in keeping them active than our present blood system. Even just the engineering and design problems in doing that makes them harder to do than they look. It's exactly that point that I was making when I said that our evolution had worked to optimize (note that word) our blood system. Yes, what is optimal for people living in one environment may not be optimal for those living in another "more modern", but that does not change the problem. I am sure that this will not answer all your questions, but it's my bedtime now and I want some sleep. More later. Best wishes and long long life for all, Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=21194