An interesting term for an interesting concept with interesting ramifications. Even its origins are interesting.

In “Tuning in to Technology’s Past” , an article in today’s Technology Review, Thomas Hughes defines “reverse salients” as “components in the system that have fallen behind or are out of phase with the others.” Why not call these “mistakes,” or “failures in planning,” or even what happens when castles in the air turn out–surprise–not to have a foundation? Because they’re sites for innovation, sometimes well after the initial idea or system has been put into practice. As Tom Standage explains,

As Edison’s electricity system expanded, for example, it became apparent that it could only supply electricity efficiently within a couple of kilometers of a generator. This reverse salient, identified by other inventors, led to the development of alternating-current distribution. Charting the development of technological systems, and spotting which parts are falling behind, can help innovators decide where to focus their efforts.

One challenging implication emerges for me: while it’s true that if you fail to plan you plan to fail, innovation should often go forward even if the plan seems incomplete. No plan can anticipate every exigency. And a great idea will always carry with it “reverse salients” that may kill it in its cradle–or may provide opportunities for innovation and even greater development than the initial vision anticipated. It’s an interesting way to look at risk, and an interesting way to think about how the past lies in wait for the future, or vice-versa.

A quick Google search turns up 1720 hits on “reverse salient.” One particularly interesting essay is called “Perpetual Uncertainty”. It’s short and rich and, unexpectedly, on the website of the Federal Reserve Bank of Boston.