Today, we wonder who feasts upon whom. The
University of Houston's College of Engineering
presents this series about the machines that make
our civilization run, and the people whose
ingenuity created them.
I've just read the most
remarkable book, The Human Condition,
by historian William McNeill. McNeill writes human
history in 78 pages by telling it in terms of
microparasites and macroparasites.
Microparasites are any of the small forms that live
off us -- micro-organisms, funguses, insects, or
small animals like mice and rats. McNeill suggests
the word macroparasites for humans who feed on
other humans. It may sound a bit like Marxist
theory, but people who produce no material goods
are in danger of being called parasites. However,
modern societies depend on vast divisions of labor.
We cannot function unless many people serve the
common good in ways that don't directly produce
Older, more primitive societies had far less
division of labor. In those societies you either
produced goods for survival or you were a parasite.
So McNeill traces the way parasites (large and
small) follow, and even shape, the formation of
We really opened ourselves to serious attacks of
microparasites when we gave up hunting and
gathering and took up agriculture. As we formed
more population-dense, and static, settlements, we
made better targets for epidemic disease and
infestations. Planted crops are more vulnerable to
fungus or insect attack than wild ones. Diseases
can't prosper in a human population until it's
large enough to let them move from hosts who've
been rendered immune into fresh hosts who have not.
That's why chicken pox and mumps are so often
children's diseases. For millennia, epidemic
diseases served as agents of population control.
Now we're just trying to learn to control
population without that kind of help.
Forming into communities led to the creation of
surplus goods, and that left us open to
macroparasites -- to thieves, then war-lords who
levied taxes. But thieves mutated into tradesmen
who served farmers by moving goods in ways that
served their interests. Taxation mutated into
more-nearly-agreed-upon means for fulfilling needs
of the people who produced goods.
As trade routes opened up, a commerce in
microparasites attached itself to trade as well.
The bubonic plague, for example, entered Europe on
a trading ship in 1347. At the same time trade also
created new macroparasites -- pirates and
highwaymen. Those parasites have also mutated into
defensive navies and police -- into warriors who
try to serve the common good. Those warriors in
turn often mutate into macroparasites on a global
scale -- warring armies become new agents of theft,
out to steal whole nations.
Reducing history to waves of parasites may seem
strike you as gloomy. But the view carries an odd
ray of optimism. For each macroparasite mutates.
The huckster mutates into the technologist who
reduces the labor needed to produce goods. The
witch-doctor becomes the physician or the
scientist. And hope remains alive.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds