Why Do Things Become More Complex? [[ I disclaim copyright responsibility :-) ]

[Dave Crocker <dcrocker () mordor stanford edu>]

Just came across this article in Scientific American.  Though it is
somewhat fatalistic in believing that increased complexity is
inevitable with evolution, I thought it might be relevant both to our
attempts to grow the Internet Suite and to grow the IETF...

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Why Do Things Become More Complex?

W. BRIAN ARTHUR
Scientific American, May 1993



Fifty years ago our technologies, our organizations and our lives were
less complicated than to day. Things were simpler. Most of us prize this
plainness, this simplicity. Yet we are fascinated by complexity. Lately
I've been wondering why the simple becomes complex. Is there a general
principle causing things to get more complicated as time passes? Is
complexity useful?

One good place to look for answers to these questions is the history of
technology. The original turbojet engine, designed by Frank Whittle in
the early 1930s, was beautifully simple. The idea was to propel aircraft
by a jet of highspeed air. To do this, the engine took in air, pumped up
its pressure by a compressor and ignited fuel in it. It passed the
exploding mixture through a turbine to drive the compressor, releasing
it through an exhaust nozzle at high speed to provide thrust. The
original prototype worked well with just one moving part, the compressor-
turbine combination.

Yet over the years, jet engines steadily become more complicated. Why?
Commercial and military interests exert constant pressure to overcome
limits imposed by extreme stresses and temperatures and to handle
exceptional situations. Sometimes these improvements are achieved by
using better materials, more often by adding a subsystem. And so, over
time, jet designers achieve higher air pressures by using not one but an
assembly of many compressors. They increase efficiency by a guide-vane
control system that admits more air at higher altitudes and velocities
and prevents engine stalling. They increase combustion temperatures,
then cool the whitehot turbine blades by a system that circulates air
inside them. They add bleedvalve systems, afterburner assemblies, fire-
detection systems, fuel-control systems, deicing assemblies.

But all these additions require subsystems to monitor and control them
and to enhance their performance when they run into limitations. These
subsystems in turn require subsubsystems to enhance their performance.
All this indeed improves performance-today's jet engine is 30 to 50
times more powerful than Whittle's. But it ends up encrusting the
original simple system with subsystem upon subsystem and subassembly
upon subassembly in a vastly complicated array of interconnected modules
and parts. Modern engines have upwards of 22,000 parts.

There's nothing wrong with this increase in complexity. We can admire
it. On the outside, jet engines are sleek and lean; on the inside,
complex and sophisticated. In nature, higher organisms are this way,
too. On the outside a cheetah is powerful and fast, on the inside, even
more complicated than a jet engine. A cheetah, too, has temperature-
regulating systems, sensing systems, control functions, maintenance
functions-all embodied in a complex assembly of organs, cells and
organelles, modulated not by machinery and electronics but by
interconnected networks of chemical and neurological pathways. The
steady pressure of competition causes evolution to "discover" new
functions occasionally that push out performance limits. There's
something wonderful about this-about how, over eons, a cheetah forms
from its simple multicellular ancestors.

But sometimes the results of growing complexity are not so
streamlined.  For example, 60 years ago in most universities, bringing
in and managing research grants might have occupied only a few people.
These functions now require a development department, legal department,
sponsored projects offlce, dean-of-research office, grants accounting
department, budget-control office, naval research office, technology
licensing office. In part, such growth is necessary because the
research-grant world itself is more complicated (and so complexity
engenders further complexity). But often, new bureaucratic offices and
departments become entrenched because the career interests they create
overpower any external competitive forces that might pare them away. In
1896 my own university, Stanford, had only 12 administrators. It is
still leaner than most, yet now it has more administrators than the
British had running India in the 1830s.

It's that way with our lives, too. As we become better off, we gain more
ways to squeeze more performance from our limited time. We acquire a
car, profession, house, computers, fitness programs, pets, a pool, a
second car. Fine.  But all these bring with them maintenance, repairs,
appointments, obligations-a thousand subactivities to keep them going.
In this case again, the overall result is increased complexity of
debatable effectiveness.

So in answer to the original question, I believe there is a general law:
complexity tends to increase as functions and modifications are added to
a system to break through limitations, handle exceptional circumstances
or adapt to a world itself more complex. This applies, if you think
about it, not just to technologies and biological organisms but also to
legal systems, tax codes, scientific theories, even successive releases
of software programs. Where forces exist to weed out useless functions,
increasing complexity delivers a smooth, efficient machine. Where they
do not, it merely encumbers.

But, interestingly, even when a system gets lumbered down with
complications, there is hope. Sooner or later a new simplifying
conception is discovered that cuts at the root idea behind the old
system and replaces it. Copernicus's dazzlingly simple astronomical
system, based on a heliocentric universe, replaced the hopelessly
complicated Ptolemaic system. Whittle's jet engine, ironically, replaced
the incurably complicated piston aeroengine of the 1930s before it also
became complex. And so growing complexity is often followed by renewed
simplicity in a slow back-and-forth dance, with complication usually
gaining a net edge over time.

The writer Peter Matthiessen once said, "The secret of well-being is
simplicity." True. Yet the secret of evolution is the continual
emergence of complexity. Simplicity brings a spareness, a grit; it cuts
the fat. Yet complexity makes organisms like us possible in the first
place. Complexity is indeed a marvel when it evolves naturally and
delivers powerful performance. But when we seek it as an end or allow it
to go unchecked, it merely hampers. It is then that we need to discover
the new modes, the bold strokes, that bring fresh simplicity to our
organizations, our technology, our government, our lives.



[W. BRIAN ARTHUR is Mowison Professor of Economics at Stanford and
external professor at the Santa Fe Institue, where he investigates the
economy as an evolving, complex system.]