FlyingSquid , 4 months ago

We have no idea if there have never been two people with the same fingerprints. It’s never been tested and there’s no way to test it since the majority of people who have existed are now dead. I would say that puts that claim squarely in myth territory until there can be some way to show that it’s true beyond “we haven’t found two matching sets out of the small subset of people we’ve fingerprinted.”

Anyway…

The real problem, Cole notes, is that fingerprinting experts have never agreed on “a way of measuring the rarity of an arrangement of friction ridge features in the human population.” How many points of similarity should two prints have before the expert analyst declares they’re the same? Eight? Ten? Twenty? Depending on what city you were tried in, the standards could vary dramatically. And to make matters more complex, when police lift prints from a crime scene, they are often incomplete and unclear, giving authorities scant material to make a match.

So even as fingerprints were viewed as unmistakable, plenty of people were mistakenly sent to jail. Simon Cole notes that at least 23 people in the United States have been wrongly connected to crime-scene prints.* In North Carolina in 1985, Bruce Basden was arrested for murder and spent 13 months in jail before the print analyst realized he’d made a blunder.

smithsonianmag.com/…/myth-fingerprints-180971640/