In this chapter, Johnson explores the role of error in innovation and scientific discovery. The chapter begins with the story of Lee de Forest, an inventor who developed the Audion in the early 20th century. Johnson details how de Forest’s invention process was marked by numerous misconceptions and errors, yet ultimately led to a groundbreaking device that revolutionized electronics. The author uses DeForest’s story to illustrate a broader point about the importance of error in innovation. He argues that many transformative ideas in science and technology have emerged from mistakes, contaminations, or unexpected results. Johnson provides several examples, including Alexander Fleming’s discovery of penicillin and Louis Daguerre’s development of the daguerreotype.

The chapter then shifts to the story of Wilson Greatbatch, who invented the implantable cardiac pacemaker. Johnson describes how Greatbatch’s invention resulted from a combination of a slow-forming idea and a fortuitous mistake in selecting components. This example further reinforces the author’s argument about the generative power of errors when combined with persistent thinking about a problem.

Johnson discusses the views of various thinkers on the role of error in discovery. He cites William Stanley Jevons, who argued that great minds often make more errors than less vigorous ones, but these errors are part of the process of generating and testing hypotheses.