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Progress toward Cyberimmortality
links such as that gives requires someone in a giver relation-
ship and someone in a receiver relationship.
Nobody knows how many episodes an adult remembers,
but the number 50,000 is sometimes mentioned in Cognitive
Science discussions. If Shastri is right, then a computer model
of the hippocampal system might not need to be very big. If
concepts are addressed efficiently in other parts of the brain,
then an episode like John gave Mary a book could be stored
in fewer than a hundred bytes. This would imply the entire
hippocampal system could get by with only 5 megabytes of
memory, a tiny fraction of the memory of todays pocket com-
puters. Shastri notes that the human mind imaginatively fills
in the missing details of memories, and each episodic memory
really has very little information in it. We are not generally
conscious of the yawning gaps in our memory, any more than
we are conscious of the blind spot in the vision of each of our
eyes. Shastri also notes that memories are generally stored in
multiple copies, perhaps to guard against losing them through
the death of any single neuron, but the redundancy in memory
may have other functions as well, such as helping us combine
facts from different sources by placing some copies of them
nearer to each other. Computerized memories might not need
that redundancy.
This very quick summary of the current state of AI suggests
that we really cannot predict how soon computer and infor-
mation scientists will be able to simulate real human minds.
Rapid progress is going on in other directions, and in a few
years a renewed interest in duplicating human intelligence
could plausibly move forward very quickly by exploiting all
the discoveries and inventions that are being made now for
other purposes. Once we know how to duplicate a mind in a
computer, then we will know far better how much informa-
tion of what kinds we will need. We do not currently have this
knowledge, but such rapid progress is being made in several