X-Message-Number: 25956 Date: Fri, 1 Apr 2005 09:17:30 -0500 From: Thomas Donaldson <> Subject: reply to Yvan Bozzonetti To Yvan Bozzonetti: Sorry, but you haven't dealt with my comment at all. The most crucial point about our dentate gyrus, which is a part of our hippocampus, is that it CREATES AND USES NEW NEURONS. You haven't answered that part of my comment at all. As for using a faster brain with fewer processors, that creates a problem, too. We're talking about a parallel system in which many different processors all do different things. In normal computing terminology a processor does one thing at any instant of time. Sure, if its fast enough we slower humans may think that it's doing these things simultaneously, but that's not what's happening. And when you have different processors (neurons) each doing something different, there's no way to collapse them into only one processor. Even when different processors only sometimes do different things, the same problem occurs. This is of course why computer people are so interested in parallel processing. If you want to solve a single VERY LARGE matrix problem, the best way to do so is to break the problem up into pieces and have different processors do each piece, and then make the step of combining them as parallel as you can. No matter how fast your individual processors may be, you can make a computer even faster by having them work as much as possible in parallel. When we consider the millions of neurons in your upper brain, it ceases to be at all obvious that we can imitate them with faster but fewer processors. There are just too many --- perhaps someday, but not soon. But the most critical point remains growth and change, which you did not discuss at all. Neurons appear and disappear, and so do their connections (synapses). And as a postscript, I'll add that I'm not saying that neurons can't be improved, or that some system with the same characteristics might be built of quite different materials than biological brains. I am saying that unless you can produce a system with as much growth and change as a brain, your belief that you can build a brain is a delusion only. Best wishes and long long life for all, Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=25956