Henry Petroski

As engineers, we were going to be in a position to change the world - not just study it.

Too much redesign has to do more with fad and fashion than with fitness and function. It is change for the sake of change. Such redesign is not only unnecessary, it is all too often also retrogressive, leading to things that work less effectively than those they were designed to replace.

Failures are much more dramatic than successes, and people like drama. I think this is why automobile races draw such crowds. People expect spectacular crashes, which we tend to find more interesting than cars just racing around the track. The same is true of bridges, buildings, or any structure or machine.

Because every design must satisfy competing objectives, there necessarily has to be compromise among, if not the complete exclusion of, some of those objectives, in order to meet what are considered the more important of them.

We call the fates of the Titanic and the Concordia - as well as those of the space shuttles Challenger and Columbia - 'accidents.' Foreseeing such undesirable events is what engineers are expected to do. However, design trade-offs leave technological systems open to failings once predicted, but later forgotten.

No design, no matter how common or seemingly insignificant, is without its adamant critics as well as its ardent admirers.

It seems to be a law of design that for every advantage introduced through redesign, there is an accompanying unintended disadvantage.

I have always been fascinated by the way things work and how they came to take the form that they did. Writing about these things satisfies my curiosity about the made world while at the same time giving me an opportunity to design a new explanation for the processes that shape it.

You can almost say that a design error is a human error because, after all, it's we humans who do the designing.

Design is nothing if not decision making.

All conventional wisdom has an element of truth to it, but good design requires more than an element of truth - it requires an ensemble of correct assumptions and valid calculations.

Any design, whether it's for a ship or an airplane, must be done in anticipation of potential failures.

Everything we do is designed, whether we're producing a magazine, a website, or a bridge. Design is really the creative invention that designs everything.

Successful design is not the achievement of perfection but the minimization and accommodation of imperfection.

I was always told that I was good in mathematics, and I guess my grades and standardized test scores supported that. My worst subjects were those that generally involved a lot of reading - English and history. So, having good test scores in math and mediocre ones in reading, I was naturally advised to major in engineering in college.

Science is about knowing engineering is about doing.

The space shuttle was designed, at least in part, to broaden our knowledge of the universe. To scientists, the vehicle was a tool; to engineers, it was their creation.

I employ case studies of failure into my courses, emphasizing that they teach us much more than studies of success. It is not that success stories cannot serve as models of good design or as exemplars of creative engineering. They can do that, but they cannot teach us how close to failure they are.