system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 how was it proved that every person has unique fingerprints?
gpt
It isn't proven. It's simply *wildly unlikely* that a randomized, complex, detailed pattern is going to turn out the same for multiple people. 

For example, say your phone unlocks with your fingerprint. There might be someone out there, somewhere, with fingerprints that *just happen* to match the same dozen spots that your phone checks. But the odds that this person exists somewhere *and they're trying to get into your specific phone* are effectively 0%.