Today, we cut with Occam's Razor. 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 old Shaker tune,

'Tis a gift to be simple, 'tis a gift to be free;
'Tis a gift to come down where you ought to be

should be the first chapter in any book on engineering design. It was a lesson I fell into when the Army got me, two years after I finished college. They put me in the Signal Corps Engineering Labs, designing research equipment. There I met a fine designer named Jules Soled -- a guy who could clearly teach me things. So I said to him, "Teach me, and I'll work for you."

And teach me he did -- many things -- things I hadn't learned in school. But his first and last lesson was always this: "Do a first design and then attack it. Your first design will be elegant and complicated. But it'll always work better when you get rid of complication. In a really good design," he said, "you eventually make the very design itself unnecessary." And this, he told me, is very hard to do, because we like complication.

An early proponent of this idea was William of Occam, a 14th-century scholastic. He told us we should make no more assumptions than we really needed to explain anything -- that the simplest explanation is best. We call this idea "Occam's Razor," because it helps us cut away the junk in our thinking.

Look at the safety razor. For years designers fought with the problem of loading, mounting, and unloading a blade in a holder. Some of you might remember Schick's "Push-pull, click click" ad for its mechanism. Keeping the action workable and the blade solidly in place was a big problem.

Then some bright person applied Occam's razor to the razor-mounting problem. He realized you could simply mold the blade right into the plastic packaging. Now who buys replaceable razor blades? Instead, we set the blades -- very solidly and with great precision -- right into a cheap throw-away piece of plastic. We've designed blade-holding mechanisms right out of existence.

That sort of thing takes nerve as well as imagination. We're so tempted to look smart by mastering, not simplicity, but complication. If we go back to our Shaker tune,

'Tis a gift to be simple, 'tis a gift to be free.

the second line says:

'Tis a gift to come down where you ought to be

Good design exacts a price from our egos. But it really is a gift -- it really is freedom -- to find the simplicity in things -- to finally reduce an engineering design down to where it ought to be.

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

(Theme music)

This episode has been greatly revised as Episode 1470.