To Engineer Is Human: The Role of Failure in Successful Design

A good judgment is usually the result of experience. And experience is frequently the result of bad judgment. But to learn from the experience of others requires those who have the experience to share the knowledge with those who follow.

No one wants to learn by mistakes, but we cannot learn enough from successes to go beyond the state of the art. Contrary to their popular characterization as intellectual conservatives, engineers are really among the avant-garde.

Engineers ... are not superhuman. They make mistakes in their assumptions, in their calculations, in their conclusions. That they make mistakes is forgivable; that they catch them is imperative. Thus it is the essence of modern engineering not only to be able to check one's own work but also to have one's work checked and to be able to check the work of others.

Failure analysis is as easy as Monday-morning quarterbacking' design is more akin to coaching. However, the design engineer must do better than any coach, for he is expected to win every game he plays. That is a tough assignment when one mistake can often mean a loss. And when defeat occurs, all one can hope is to analyze the game films and learn from the mistakes so that they are less likely to be repeated the next time out.

It is the process of design, in which diverse parts of the “given-world” of the scientist and the “made-world” of the engineer are reformed and assembled into something the likes of which Nature had not dreamed, that divorces engineering from science and marries it to art.

Galileo's analysis of the cantilever beam illustrates an extremely important point for understanding how structural accidents can occur: he arrived at what is basically the right qualitative answer to the question he posed himself about the strength of the beam, but his answer was not absolutely correct in a quantitative way. He got the right qualitative answer for the wrong quantitative reason.