Engines of Our Ingenuity

No. 1989:

by John H. Lienhard

Today, I have a choice. 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.

Is it just me, or has a new phrase been gaining in use -- showing up in the real world as well as well as on television? It is, "I didn't have a choice." Yes, I put your case on hold, but I didn't have a choice. Yes, I'm laying you off but I don't have a choice. Yes I shot that innocent man, but I didn't have a choice.

Naturally that starts me thinking about the mechanics of choice. If someone ties me up, I truly cannot choose to walk away. But there's no decision, no free-will action, involved.

The phrase "I didn't have a choice," is another way of saying "I chose the lesser of two evils." But I certainly had a choice. Since we make such choices all the time, we have a term for them: Hobson's Choice. Hobson was a seventeenth-century livery stable owner who said to his customers, "You may either take the horse nearest the door or none at all." That's still a choice. If the horse nearest the door looks unridable, I can always walk.

This whole matter looms large in engineering design. All the time, designers want to throw up their hands and cry, "I know it'll be hard to lubricate, but I'm making it that way because I don't have a choice!" Design is life-in-microcosm -- always a complex set of constrained choices. Design is finding ways around being painted into corners. Options open up only when we refuse to accept what's obvious -- when we tell Mr. Hobson, "Fine, but I see you have a back door. Give me the fine mare next to it."

James Watt seemed to have no choice after he saw why existing steam engines were inefficient. Steam entered a cylinder; then cold water was squirted in to condense it, and the vacuum pulled on the piston. When the next charge of steam entered, the cylinder was cold, and most of the steam was wasted in heating it back up.

Watt tried insulating cylinders. He tried making them from materials of different conductivity. Nothing worked. No choice -- a problem he just had to live with. But he looked for, and found, a back door to the stable. If he led the steam out of the cylinder, into a separate cold container, he could condense it there while the cylinder stayed hot. Steam engines were never the same again.

The sorry proclamation: I didn't have a choice is abdication from imagination. Kenneth Clark understood that when he said of Leonardo DaVinci, "He would not take yes for an answer."

That's a wonderful idea: Yes can be as dead an end as No. That's why a good designer keeps looking for improvement even after all the constraints have been satisfied.

We have so much more choice than we first think, even when we think we're staring down blind alleys. So, if I'm ever dumb enough to give in to the notion that I have no choice, please kick me -- remind me of Mae West's version of Hobson's Choice. She said, "When choosing between two evils, I always like to try the one I've never tried before."

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

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The Engines of Our Ingenuity is Copyright © 1988-2005 by John H. Lienhard.