Today, UH math professor Krešo Josić talks about brains, computers
and John von Neumann. The University of Houston presents this series
about the machines that make our civilization
run, and the people whose ingenuity created them.
The Hungarian American John von Neumann was the
last of the great mathematicians. He fundamentally influenced quantum
mechanics, economics, computer science ... He was one of the principal
members of the Manhattan project, and an advisor to the government on defense
policy after World War II. Cancer confined him to a wheelchair near the
end of his life. From that seat, he provided a dispassionate analysis of
nuclear strategy in accented English. He could well have been the model for
Dr. Strangelove.
Von Neumann's interest in digital computation was partly driven by the
need for fast calculations in nuclear weapon design. In the 1940s he
described the architecture used in the first modern computers. He also
showed how to construct a self-replicating automaton - a device that could
produce copies of itself. For example, he proposed that in the future we
could send a handful of robots to the Moon. These automata could reproduce
and create an entire colony which could send moon ore back to Earth.
Von Neumann argued that brains, like digital computers, process information
and should be studied the way we study computers. He summarized his views
in a lecture that he was never able to deliver. He died of cancer in 1956,
but his notes for the lecture were printed in a small book The Computer
and the Brain. Our understanding of the nervous system and of computer
technology has progressed enormously since von Neumann's time. But consider
the relevance of some of his ideas:
He asked to what extent computers and brains are alike. Neuronal cells, the
processing units of our brains, respond to inputs in an all-or-none fashion.
Their output is digital in character. Yet the brain seems to be at a distinct
disadvantage compared with a computer. Even the vacuum tubes used to process
information in the first digital computers were much faster than neurons. And
the precision with which computers and brains represents information can't be
compared.
And yet it's clear that our brains are superior in many ways: It took over fifty
years to design computers that could consistently win at chess, while artificial
intelligence still remains only a dream. A child can tell the difference between
a cat and a dog - something no machine can yet do reliably. And just think that
our brain uses about as much power as the little light bulb in your refrigerator.
How is this possible? Von Neumann pointed out that neurons in our brain work in
parallel, while computers process information serially.
By comparing computers and brains within a common framework von Neumann offered us
a new way to understand ourselves. More than that, he pointed to a future in which
people and computers may draw closer. Machines have already interfaced with brains.
We've invented cochlear implants and deep brain stimulation devices that help control
Parkinson's disease. And that connection can only become more intimate. That may
seem frightening, but consider our relationship with our mobile phone, our laptop,
our car ... When we compare that to the role machines played in our grandparent's
lives we can bet that electronic devices are destined to become part of us.
I'm Krešo Josić at the University of Houston,
where we're interested in the way inventive minds
work.
(Theme music)
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Krešimir Josić is Associate Professor of Mathematics at the University
of Houston. His primary interest is mathematical biology and network
theory. He is trying to understand how elements of different biological
networks work together to process information. He has co-edited the
volume Coherent Behavior in Neuronal Networks. (Springer, 2009).
J. von Neumann, The Computer and the Brain. 2nd ed. (see. e.g., the New Haven:
Yale University Press, 2000, reprint). This is a short and relatively easy read.
It may also be read on line by clicking here.
For more on the Manhattan project and von Neumann's role in it, see: R. Rhodes,
The Making of the Atomic Bomb. (New York: Simon & Schuster 1986). See also,
the Wikipedia article on von Nuemann. Images: Boy and robot photo by K. Josić, von Neumann
photo courtesy of Wikipedia.
The interfacing of brain and machine offers many new ethical challenges, some of which
are discussed by J. Clausen, Man, machine and in Between. Nature. 2009 Feb 26;457(7233):1080-1.
A more modern take on the difference between computers and brains
may be found in this blog.
Cartoon representation of self-replicating robots. Image courtesy of VizWiki.
The Engines of Our Ingenuity is
Copyright © 1988-2009 by John H.
Lienhard.
