Beyond one-off impact

Excerpt From: Clayton M. Christensen. “Competing Against Luck”:

When we hear the name Louis Pasteur, most of us recall that the French chemist had something to do with making milk safer to drink. In perhaps the ultimate symbol of his impact on the world, his name has given rise to a verb: to “pasteurize.” But Pasteur is responsible for so much more.

To understand how revolutionary Pasteur’s contributions were, consider the previously popular ideas that attempted to explain why people got sick. For nearly two thousand years, the medical profession believed that four different bodily fluids—blood, phlegm, yellow bile, and black bile—dominated the health and moods of people ...

Why was Pasteur so successful, after hundreds of years of searching for explanations for the mysteries of human disease? Put simply, it was because Pasteur’s work helped develop a theory—germ theory—that described the actual causal mechanisms of disease transfer. Before Pasteur, there were either crude and untestable guesses or statements of broad correlation without an underlying causal mechanism. Pasteur’s work demonstrated that germs were transmitted through a process: microorganisms, too small to see with the naked eye, that live in the air, in water, on objects, and on skin. They can invade hosts (in this case, humans) and grow and reproduce within those hosts. Identifying the process by which people get sick allowed the development of ways to prevent its spread—in effect to interrupt that process, most notably through personal and social hygiene measures. We all owe Pasteur a debt of enormous gratitude, but his contribution was far greater than even the monumental direct descendants of his work—such as pasteurization and penicillin. He helped fundamentally change our understanding of biology and played a critical role in the rapid evolution of medicine from an art to a science, saving millions of lives in the process.

Shifting our understanding from educated guesses and correlation to an underlying causal mechanism is profound. Truly uncovering a causal mechanism changes everything about the way we solve problems—and, perhaps more important, prevents them.