Photograph by W.E Fretwell

After the floods of 1926, a train had just passed over the Fremantle Bridge in Perth, Western Australia, when it collapsed.

May 17, 2011 | The biggest misperception people have about failure is that it is all bad, said Henry Petroski, a professor of engineering and history at Duke University who researches the role that failure plays in design. “But from an engineer’s point of view,” he said, “a failure can contain all sorts of helpful information.”

It reveals weaknesses, helps make things stronger and offers lessons in humility, he said.

Petroski is the author of 15 books, including “To Engineer Is Human: The Role of Failure in Successful Design” and “Success Through Failure: The Paradox of Design.” He has also written histories of the design of the pencil, the toothpick and the bookshelf.

“Failures that happened 2,000 years ago can still be instructive today,” he said. “Not that we’re trying to do the same things the ancients were doing, but we’re using the same intellectual tools those people were.”

Petroski spoke with Faith & Leadership about what he’s learned about failure from his research, how it influences his teaching, and why a bridge collapses about every 30 years. The following is an edited transcript.

Q: Why are you more drawn to stories of failure than to stories of success? What’s the value of failure?

Success stories don’t teach us anything but that they are successes. They are things to emulate, but the word “emulate” means two things. One, it means effectively to copy. Nobody wants to copy. Everybody wants to be more creative. They want to do something better. So “emulate” also implies trying to go beyond -- trying to make it better, somehow bigger, whatever the measure is.

Successes are not very interesting other than in that regard. When we do go beyond, then we move generally closer to failure. And what interests me about any failure is that it presents real lessons to be learned, because there’s no ambiguity. When something fails, it failed.

Generally, failure does several things. One, it shows us when something is not working as we had planned. That’s one definition of failure. You design something, you expect it to behave or perform a certain way. If it doesn’t, then there are lessons to be learned from that.

The earthquake in Japan is full of lessons. Nobody in Japan -- the engineers, the planners -- wanted things to happen the way they did, obviously. This earthquake and the subsequent tsunami were so overwhelmingly large compared to previous ones that the Fukushima nuclear plant was overwhelmed. Certain things that were supposed to back up and provide safety didn’t, and as a result, the accident was worse than it might have been.

But there are lessons that people can take from that -- not only the Japanese but anybody else who is designing nuclear plants in any other country and even beyond the nuclear plants. You can generalize from these things.

For example, the nuclear plant had been operating OK for years, and so you could say it was a success up until it was a failure. While it’s a success, it doesn’t teach much. All you can really logically conclude from it is that it’s a success. It’s doing the right thing. But then when something extraordinary happens and something overwhelms it, it reveals its weaknesses. That’s the value of failure.

Q: How do you, as a teacher, get your students to see the value of failure?

I use a lot of case studies and stories. Generally, I tend to use more historical ones, because those stories are fixed and static.

I talk about things that are happening now in class, too, but always with the caveat that “This is what we know as of today. Tomorrow there may be something new that comes out.” If we, again, go to what’s happening in Japan right now, every day there’s a different story in the news, and it gives us a different perspective. It’s sort of a moving target.

It’s still a valid teaching tool, but I like to use historical case studies, because they are more fixed in time. I also like to use them because they have valuable lessons for the present and the future.

I give my students readings that go back to Vitruvius’ “De Architectura,” which is a book that was written in the first century [B.C.] about Roman and Greek architecture that talks about failures back then. The lessons in there are as clear as if we’re talking about something that is in the newspaper today.

I also read with them from the work of Galileo from the 17th century. He opens up one of his books talking about a whole bunch of failures. He basically uses them to say, “Well, we Renaissance engineers don’t quite have it all figured out yet. What are we missing?” And it’s that attitude -- that context of failure -- that helps the students get started on figuring it out.

I like to see students come out of my courses with a collection of these horror stories or these failure stories, so that if they’re engineering students and they’re designing something someday, they’ll say, “You know, what we’re doing reminds me of what they did to that thing that failed back in the 19th century,” because, it turns out, there are very similar ways in which things fail.

The same human mistakes tend to be repeated over and over and over.