Apple, Touch ID and the fear having your finger chopped off

September 16, 2013, 2:15 PM UTC

iPhone 5S with Touch ID. Photo: PED

FORTUNE — In traditional Freudian analysis, dreams of losing a hand or a finger signify a deeper fear of castration. Could that explain the obsession with amputated digits among the staff of Henry Blodget’s Business Insider?

Even before Apple (AAPL) unveiled its new fingerprint recognition  system at last Tuesday’s iPhone event, BI’s Jay Yarow had raised the specter of a thief chopping off a finger to unlock an iPhone 5S protected by Touch ID.

By the next morning, Yarow’s colleague Jim Edwards had read a back issue of Scientific American, consulted a couple of doctors (including his mom) and posted a column advising readers which finger (or toe) in such a situation they would miss the least. (Answer: The index finger of your non-dominant hand or the fourth toe on the foot you don’t kick a soccer ball with.)

Edward’s piece was especially bizarre because the question of whether a dead finger could unlock an iPhone 5S had already been answered.

It can’t.

“The iPhone 5S’s fingerprint reader relies on “the living layer of skin under the surface of your finger,” Yarow had written the day before, quoting CITEWorld‘s Mary Branscombe.

Mashable‘s Adario Strange reached the same conclusion Saturday after talking to an expert at Validity Sensors, a California-based provider of fingerprint sensor solutions.

“The [RF capacitive sensor] technology is built in a way that the [fingerprint] image has to be taken from a live finger,” says Sebastien Taveau, Validity’s chief technology officer. “No one in biometrics wants to talk about cut fingers and dead bodies, but at the end of the day we are still asked to remove the fears of consumer and make sure that they understand that [a severed finger] will not work.”

“Remove the fears” is an unfortunate phrase in this context. Especially since Strange had just re-told the story a machete-weilding Malaysian gang that chopped off the index finger of a robbery victim in 2005 in order to restart his stolen Mercedes S-class car.

UPDATE: The topic has already been thoroughly chewed over on Investor Village’s AAPL Sanity board, where one wag claimed Sunday that all phones — even Androids — are susceptible.

“If you begin the process of cutting off an Android phone owners finger,” he wrote, “he’s going to tell you his password.”