Engines of Our Ingenuity

No. 1162:

by John H. Lienhard

Click here for audio of Episode 1162.

Today, let's see how machines transcend themselves. 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.

The word system is one that keeps growing in importance. A system is a set of parts which accomplish something by relating to one other. Drive a bolt through a pair of blades and the three parts form a system we call scissors. As a scissors they're more than two blades and bolt. Systems have meaning beyond their parts.

As machines grow more complex, their systemic character grows more subtle and it expands outward. An automobile engine is large and complex. But it isn't very meaningful until it joins the radiator, transmission, brakes, suspension and everything else that forms a car. And the system doesn't stop there. Cars interact with life around them. Questions of highways, gas pumps, service, air quality, parking, safety, all come back to automobile makers.

So the parts of an engine make up a system that reaches beyond the engine, beyond the car, even beyond their obvious infrastructure. Before they're done, cars reshape city layout, affect home design, and rescale the size of families.

As the scope of our systems increases, something else changes as well. The actual members of a given system may differ from one day to the next. In 1850 the city of Houston was a completely different assembly of buildings, people, and infrastructure than it is now. Yet the system we call Houston endures. Far from being a mere assembly of parts, a system is a mutating relationship among the inconstant parts that make it up.

As the system increases in scope from scissors to car to city, the interrelation among parts becomes far more important than the parts themselves. Engineers have to focus as intently on those relationships as they once focused on parts. And a new term, systems engineering, is creeping into our vocabulary.

A few years back, some of my engineering colleagues joined with historians, economists, philosophers, and business people in an ad hoc Systems Seminar. I guess it's no surprise they were soon talking about Gaia. Gaia is what we call the biosphere when we see it as a single living system -- a single fragile spherical shell of animal, plant and bacterial life surrounding Earth. Since all life is interdependent, it forms one living being. To deal with our own presence in the environment, we have to recognize the one system we all belong to.

But there we're in trouble. Who can grasp the totality of that one vast system from inside it? If we try to reach all the way from scissors to Gaia we founder on vague generalities. Instead, we have to move outward, step by step, away from specific parts we understand. That learning process is the hardest problem engineers face today, whether we're making scissors, building the internet, or tackling the most essential task of all -- caring for Gaia.


(Theme music)

I am grateful to Robert Finch, UH Mechanical Engineering Department, for his very helpful discussions of the problem of defining and dealing with systems.


A simple engineering system

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