BIOLOGICAL INSPIRATION FOR COMPUTING 251
based on biological systems to function more effectively than models constructed using more tradi-
tional techniques.
One of biology’s most important roles is that it can serve as an existence proof of performance—that
some desirable behavior is possible. The reasoning is that if a biological system can do something
interesting, why can’t an artificial system to the same thing? Birds fly, so why shouldn’t people or
constructed artifacts be able to fly? Many biological behaviors and functions would be desirable in a
computing context, and biological systems that exhibit such behavior demonstrate that this behavior is
possible.^5
Existence proofs are important in engineering. For example, in the view of many nuclear scientists
associated with the Manhattan Project, the information that was most critical to the Soviet develop-
ment effort was not a secret gained through espionage, but rather the fact that a nuclear explosion was
possible at all—and that fact was reported in every major newspaper in the world.^6 In other words, it
is one thing to work toward a goal that may well be impossible to achieve and an entirely different
psychological matter to work toward a goal whose achievement is known—with certainty—to be
possible.
An example of using a biological metaphor for understanding some dimension of computing re-
lates to computer security. From many centuries of observation, it is well known that an ecology based
on a monoculture is highly vulnerable to threats that are introduced from the outside. With this insight
in mind, many expert observers have used the term “monoculture” to describe the present-day security
environment for desktop computers in which one vendor dominates the operating system market. This
report does not take a position on whether such a characterization is necessarily accurate,^7 but the point
is that the metaphor, used in this manner, can determine the terms of discussion and thus provide a
useful way of looking at the issue.
Despite its conceptual value, an existence proof does not speak directly to how to build the artifact
so that it does the same thing. That is, existence proofs do not necessarily provide insight about con-
struction or creation. Diversity as a strategy for survival does not necessarily indicate how much or
what kinds of diversity would be helpful in any given instance. Similarly, aerodynamics is a body of
theory that explains the flight of birds, and also enables human beings to design airplanes, but a study
of birds did not lead to the airplane. For construction or creations, a deeper understanding of biology is
required. Knowing what kind of deeper understanding is possible potentially leads to at least three
additional roles for biology:
- Biology as source of principles. Nature builds systems out of the same atoms that are available to
human engineers. If a biological system can demonstrate a particular functionality, it is because that
system is built according to principles that enable such functionality. The hope is that upon close
examination, the physical, mathematical, and information-processing principles underlying the inter-
esting biological functionality can be applied through human engineering to realize a better artificial
system. Note also that in some cases, the actual principles underlying some biological functionality may
be difficult to discern. However, plausibility counts for a great deal here, and biology may well provide
inspiration for engineered artifacts if human beings propose a set of plausible principles that govern the
behavior of interest in an actual organism, even if those principles, as articulated, turn out not to have a
biological instantiation in that organism. (Note that in this domain the division between “applying
(^5) An accessible and more extended discussion of these ideas can be found in J. Benyus, Biomimicry: Innovation Inspired by Nature,
William Morrow, New York, 1997.
(^6) D. Holloway, Stalin and the Bomb: The Soviet Union and Atomic Energy, 1939-1956, Yale University Press, New Haven, 1994.
(^7) For example, it may be that even though the number of operating system platforms is small compared to the number of
desktop computers in use, different computer configurations and different operational practices might introduce sufficient
diversity to mitigate any system-wide instabilities. Furthermore, replication has many other advantages in the computer context,
such as easier interoperability.