Privacy-preserving Proof of Personhood

Proof of personhood is one of the most pressing problems on the internet. In an age of bots and account farms, how do we enable online voting or distribution of power when anyone can pretend to be thousands of people all at once? Worldcoin hopes to solve this problem by using biometric data from the eye to validate identity. They want to use this system to enact universal basic income for over one million people without having to deal with welfare fraud.