Affection for 'Inflection'? We Get the Point

By Rob Kyff

October 16, 2019 3 min read

When it comes to the use — and overuse — of "inflection point," we're clearly at an inflection point.

"Cellphones were a significant inflection point. They made it possible for us to be available at virtually any moment," wrote Jeff Giles in The New York Times last July.

"With the Raiders moving to Las Vegas next season, this year is an inflection point," wrote sports reporter Mitchell Gladstone in Sports Illustrated last August.

"If we're at an inflection point in climate policy, then this issue of tailpipe emissions ... is the game-changer," California Gov. Gavin Newsom told The New Yorker last month.

Most people seem to be using the term as a synonym for "turning point" or "tipping point" — a point of significant change. But where did this trendy term originate?

The noun "inflection," derived from the Latin "flexere" (to bend), entered English in the 1530s with the meaning "the act or result of curving or bending." Two hundred years later, the term "inflection point" emerged in the field of differential calculus meaning "a point on a continuous curve at which a change in the direction of curvature occurs."

Say what?

Picture a roller coaster car descending a steep slope as it heads toward an upcoming steep ascent. The inflection point on the descending car's curve is not, as you might expect, the point at the bottom where it starts to ascend.

Instead, it's located halfway down the slope when its angle of descent starts to decrease as it approaches the upward slope. The roller coaster car is still descending; it's just not descending as steeply.

So the original mathematical term refers not to a point of dramatic turnaround but instead to the point where the angle or rate of descent or ascent on an arc starts to change.

Appropriately enough, the popularity of "inflection point" has been on a roller coaster. A Google Ngram search reveals that its use surged from 1920 to the early 1960s, perhaps propelled by references to parabolic trajectories in the growing fields of rocketry and space exploration. But its frequency faded during the 1990s and 2000s, only to rise again as its metaphoric use increased during the past few years.

Because the inflection point denotes the beginning of change rather than a sudden or complete change, some mathematicians cringe when they hear inflection point used as a synonym for turning point or tipping point.

But let's face it: "Inflection point" sounds cerebral, sophisticated and cool. Brace yourself for an inflection affliction.

Rob Kyff, a teacher and writer in West Hartford, Connecticut, invites your language sightings. Send your reports of misuse and abuse, as well as examples of good writing, via email to [email protected] or by regular mail to Rob Kyff, Creators Syndicate, 737 3rd Street, Hermosa Beach, CA 90254.

Photo credit: Incygneia at Pixabay

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