TITLE: Computational Processes in Nature
AUTHOR: Eugene Wallingford
DATE: July 03, 2007  8:02 AM
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Back in February I wrote a speculative piece on
<A HREF="http://www.cs.uni.edu/~wallingf/blog/archives/monthly/2007-02.html#e2007-02-08T18_23_50.htm">
   computer science as science</A>,
in which I considered ways in which CS is a
scientific discipline.  As a graduate student, I grew
up on
<A HREF="http://www.psy.cmu.edu/psy/faculty/hsimon/hsimon.html">
   Herb Simon</A>'s
book
<A HREF="http://www-static.cc.gatech.edu/~jimmyd/summaries/simon1969-a.html">
   The Sciences of the Artificial</A>,
so the notion of studying phenomena that are contingent
on the intentions of their designer has long seemed a
worthwhile goal.  But "real" scientists, those who study
the natural world, have never been persuaded by Simon's
arguments.  For them, science deals with natural phenomena;
programs and more comprehensive computer systems are
man-made; and so computing as a science of the artificial
is not a real science.

As the natural sciences develop, though, we have begun to
learn something that computer scientists have sensed for
a long time: computational processes occur in the natural
world.  Peter Denning has taken dead aim on this observation
in his new essay
<A HREF="http://portal.acm.org/citation.cfm?id=1272516.1272529">
   Computing is a Natural Science</A>,
published in this month's <EM>Communications of the ACM</EM>.
He opens with his take-home claim:

<BLOCKQUOTE><EM>
Computing is now a natural science.  Computation and
information processes have been discovered in the deep
structures of many fields.  Computation was present long
before computers were invented, but the remarkable shift to
this realization occurred only in the last decade.  We have
lived for so long in the belief that computing is a science
of the artificial, it may be difficult to accept that many
scientists now see information processes abundantly in nature.
</EM></BLOCKQUOTE>

Denning supports his claim with examples from biology and
physics, in which natural computations now form the basis
of much of the science, in the form of DNA and quantum
electrodynamics, respectively.  In many ways, the realization
that computation lies in the deep structures of many natural
systems is a vindication of Norbert Wiener, who in the 1940s
and 1950s wrote of information as a fundamental element of
systems that communicate and interact, whether man-made or
living.

The article continues with a discussion of some of the
principles discovered and explored by computer scientists,
all of which seem to have correlates in natural phenomena.
The table in his paper, available on his web site as a
<A HREF="http://cs.gmu.edu/cne/pjd/PUBS/CACMcols/cacmJul07.pdf">
   PDF file</A>,
lists a few key ones, such as intractability, compression,
locality, bottlenecks, and hierarchical aggregation.  That
these principles help us to understand man-made systems
better and to design better systems should not distract
from their role in helping us to understand computations
in physical, chemical, and biological systems.

There is some talk on my campus of forming a "school of
technology" into which the Department of Computer Science
might move.  From my department's perspective, this idea
offers some potential benefits and some potential costs.
One of the potential costs that concerns me is that being
in a school of technology might stigmatize the discipline
as merely a department of applications.  This might well
limit people's perception of the department and its
mission, and that could limit the opportuniies available
to us.  At a time when we are working so hard to help
folks understand the scientific core of computing, I'm
not keen on making a move that seems to undermine our
case.

Explicating the science of computing has been Denning's
professional interest for many years now.  You can read
more about his work on his
<A HREF="http://cs.gmu.edu/cne/pjd/GP/">
   Great Principles of Computing</A>
web site.  There is also an
<A HREF="http://www.acm.org/ubiquity/interviews/v8i22_denning.html">
   interview with Denning</A>
that discusses some of his reasons for pursuing this line
of inquiry in the latest issue of ACM's Ubiquity magazine.
As Denning points out there, having computing as a common
language for talking about the phenomena we observe in
natural systems is an important step in helping the sciences
that study those systems advance.  That we can use the same
language to describe designed systems -- as well as large
interactive systems that haven't been designed in much detail,
such as economies -- only makes computer science all the
more worthy of our efforts.
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