X-Message-Number: 8503 From: (Thomas Donaldson) Subject: Re: CryoNet #8489 Date: Fri, 29 Aug 1997 11:01:27 -0700 (PDT) To Yvan: I don't understand your claim that LN2 is toxic. Cells have been preserved in LN2 for decades and revived afterwards. If you keep something at CO2 temperature it does still deteriorate. If you vitrify it (using some cryoprotectant as yet unknown) CO2 temperature might work. Finally, about "uploading". If the "uploading" means basically the storage of information, I have no metaphysical problems about uploading. However I'd add that if you want a difficult problem in 1997 practice the problem of uploading looks far harder than vitrification. In the first place, to upload we must first understand how our brain works, which we don't yet do. Secondly, we want some way to upload a 3 D scan of brain structure AND chemistry on a microscopic scale. Not only that, but ideally this scan must NOT be immediately destructive, so that we may check it for correctness before we destroy the original tissue. That's a hard physics and electronics problem. Not only this, but even for those now suspended and those suspended under poor conditions (which you quite correctly point out will go on for some time even with full suspended animation possible under GOOD conditions) we are left with freezing as the most likely form of storage. Any improvements here will decreasethe destruction caused by suspension and thus make revival easier... and upload- ing easier too, if ultimately we go that route. Basically I think "uploading" is too often just a copout, and would challenge anyone who proposes it to explain just how to do it. NOW. We do have ideas on how to improve our freezing methods. Those who favor uploading as a strategy for 1997 should provide their own ideas as to how to do it. Best and long long life, Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=8503