They are "No two people have the same fingerprints" and "No two snowflakes are alike."
These are axioms that are impossible to prove/disprove, but are accepted as fact.
The first is impossible to prove/disprove as we do not have fingerprints for every one alive, and we don't have complete records for those that have lived before. While fingerprint for use in crime investigation does go back to the Babylonian king Hammurabi (1792-1750 BCE), complete fingerprinting was rare. So given the billions of people that have lived before and the 7 billion plus that are alive now, I feel that it is very unlikely that no two people never have the same fingerprints.
With snow it is much the same story, with the addition of examining snow crystals is that much harder. Given the incalculable number of snowflake that have fallen in the 4 billion plus years the Earth has been around to definitely say the no two snowflakes have the same pattern is bordering on hyperbole. It would be better to say, "It is unlikely that no two snowflakes have the same pattern."
These are axioms that are impossible to prove/disprove, but are accepted as fact.
The first is impossible to prove/disprove as we do not have fingerprints for every one alive, and we don't have complete records for those that have lived before. While fingerprint for use in crime investigation does go back to the Babylonian king Hammurabi (1792-1750 BCE), complete fingerprinting was rare. So given the billions of people that have lived before and the 7 billion plus that are alive now, I feel that it is very unlikely that no two people never have the same fingerprints.
With snow it is much the same story, with the addition of examining snow crystals is that much harder. Given the incalculable number of snowflake that have fallen in the 4 billion plus years the Earth has been around to definitely say the no two snowflakes have the same pattern is bordering on hyperbole. It would be better to say, "It is unlikely that no two snowflakes have the same pattern."