This is an email from RE: Engineering, a newsletter by Eiffel’s Paris — an Engineer’s Guide.

How Do Engineers Know What They Know?


Do engineers have a distinctive way of learning similar to the “scientific method?” Science and engineering share many characteristics. Both are fact-based professions that require rational, methodical thought. And engineers rely heavily on knowledge produced by science.

But, scientists and engineers pursue fundamentally different aims, as illustrated in this quote from the famous physicist and aeronautical engineer, Theodore von Kármán.

Scientists study the world as it is, engineers create the world that never has been. Theodore von Kármán

Therefore, one might expect that engineers gather and organize information in a way that is distinctly different from scientists.

According to Harvard historian Antoine Picon, engineers have a particular way of thinking about the world — a rationality — that is the same across the diverse range of technologies engineers have created and roles that engineers play. Picon studies how engineers’ way of thinking has changed over time in order to understand how the profession has grown and developed, particularly in the period since the 18th century in Europe.

Engineers engaged both in the practice of engineering and as managers share “a certain attitude, patterns of thought and action like the systematic decomposition of a complex problem into more elementary questions, or even a certain rigidity when dealing with issues to which clear-cut distinctions do not apply — social issues, for instance,” writes Picon.

Echoing von Kármán, Picon observes that, for engineers, rationality serves primarily a guide for action. It is, therefore, inseparable from the objectives of the problem at hand. Although logical in their thinking, the rationality of engineers lacks the mathematical precision of pure logic. Engineers must take into account a number of factors that defy precise definition.

Stanford professor of aeronautical engineering Walter Vincenti, has come as close as anyone has to articulating an “engineering method.” Vincenti examined five case studies drawn from the history of the development of the airplane, a history in which Vincenti was an active contributor. At its core, the engineering method is built around the tried and true process of trial-and-error; although Vincenti prefers the term “variation-selection method.”

Vincenti observes that the generation of engineering knowledge requires the combined efforts of diverse communities of individuals. Tales of discovery by a lone genius pervade popular histories of science. By contrast, advances in engineering depend on the development and wide dissemination of shared concepts, modes of analysis and patterns of thought.

Engineers rely on two types of knowledge, which Vincenti characterizes as the knowledge of “what is” and the knowledge of “how to.” Attention to the later saves engineers from the pitfalls of “groupthink” myopia. At the end of the day, whatever engineers are working on, whatever engineers think that they know, the thing has to work.


Picon, A., 2004. Engineers and Engineering History: Problems and Perspectives. History and Technology 20:4, pp. 421–436.

Vincenti, W., 1990. What Engineers Know and How They Know It. The Johns Hopkins University Press.

Read more about the 19th century roots of the engineering profession and the 72 engineers and scientists named on the Eiffel Tower.

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William Nuttle

William Nuttle

Navigating a changing environment — hydrologist, engineer, advocate for renewable energy, currently writing about the personal side of technological progress