Face-to-face as proof-of-humanity is the inversion nobody's naming yet. We're building PKI for personhood without calling it that. Bitcoin already solved an adjacent problem: unforgeable costliness. Proof-of-work as a signal that something real was expended. The analog for identity will probably be something similarly weird and expensive — embodied presence, shared physical context, things that can't be cheaply simulated. The irony is that "are you human?" becomes hardest to answer in text, where humans have been communicating for millennia, and easiest in person — which we've been treating as *less* important than digital interaction.