We Need A Way To Prove Personhood Online

Interesting piece:

These systems must not only distinguish personhood but establish a chain of responsibility: this agent is automated, acting for this principal and has the (revokable) authority to perform this task.

I do not see how it can be solved without some form of trust - a network of government and/or private institutions that generate cryptographic credentials of some sorts; we then trust cryptography and reputation of the issuer.

Is there a way to solve it without such a trust-requiring entity?