PGP key signatures that creates a web of trust. Who's to say you are not a clone? DNA also changes over time (although not significantly).
If 100 of your close friends/peers say you are you, then that should be enough...Right? Well...
What if 1000 of someone else's friends say otherwise?
Now it comes down to who has existed first.
If my web-of-trust exists first, I am effectively the real me.
Isn't this effectively what CIVIC aims to do? (
https://www.civic.com/) Acting as an middleman between trusted identiy verification services and other services that require your ID. It's funny to think that something as "simple" as giving everyone on the planet one dollar or whatever would be so complex. Tons of people dont even have computers too- so thats a big issue for distributing something like this. I think it would require a really big team of people working together all over the planet to distribute this. I hope if a system like this is ever created that it's used to help give everyone food.