X-Message-Number: 25138
Date: Tue, 23 Nov 2004 05:53:31 -0500
From: Thomas Donaldson <>
Subject: CryoNet #25130 - #25137

FOR Yvan Bozzonetti:

The problem with FPGAs is that they're far too small and lack all
the connections needed. If we were to try to implement a brain 
with FPGAs, we'd set up one for each (overlapping) set of neurons
which might form connections depending on the information they
receive. The number of ACTUAL connections will always be limited,
but the number of POSSIBLE connections will be much larger; and
note that we'll need at least one for every neuron, and probably
more than one because neurons communicate by other than electrical
means, too. Moreover the range to which a neuron can grow a connection
is fuzzier and generally larger than the range to which it has actually
grown connections. This means that if you want your FPGAs to construct
a brain, they'll have to contain potential connections between each 
neuron at a much larger range. (One way they're too small). And remember
that an FPGA isn't the neuron itself, it's aimed at producing the 
CONNECTIONS of a neuron.

Again, it's essential to the working of our neurons that their 
connections are changeable and none of them must persist. If I 
understand how FPGAs work, we can program them once but not more
than once. So that we'd want changeable FPGAs.

This is why I do not believe we now have the technology to imitate
a HUMAN brain. As I said before, given especially that neural 
connections are NOT fixed, it looks to me that growing connections
makes a lot more sense than beginning with a device containing all
possible connections and then pruning them down. And it makes more
and more sense the bigger the brain becomes.

Besides, just what's your prejudice against devices that act biologically,
anyway? A variable FPGA might turn out to be a quite valuable device,
even if it's not made with silicon.
        
              Best wishes and long long life for all,

                    Thomas Donaldson

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