Scientists describe. Engineers decide.

The May, 2018, issue of Mechanical Engineering magazine included the article "Without Engineering, Civilization Does Not Exist" by Adrian Bejan.  I wrote the following letter about this article; my letter appeared in the July 2018 issue.

To the Editor:

I wholeheartedly concur with Adrian Bejan's conclusion that engineering has transformed our society for the better.  Unfortunately, Professor Bejan's definition of engineering as type of science was inaccurate, which contributes to the public's misunderstanding of our profession.

The article stated that "engineering is a science of what is useful" and "engineering is [a] body of science."  It concluded by repeating that engineering is "the science of useful things."

Although engineers need to learn science and some scientists do some engineering, engineering is not a type of science, for it has a different objective.  Scientists study the world in order to understand it, but engineers design new products and systems.  Scientists describe; engineers decide.  Henry Petroski discussed this distinction and provided more ways to view it in An Engineer's Alphabet.  Professor Bejan was closer to the truth when he described engineers as those who "are developing new contrivances and improving old ones."

Jeffrey W. Herrmann