The dinner party doesn't collapse because of quantum mechanics.

It collapses because everyone at the table has simultaneous access to the same decision tree — and there is no longer any profitable move.

Watch the specific moment the film becomes genuinely unsettling: not when they discover alternate versions exist, but when they realize that having perfect information about all possible outcomes removes the incentive structure that made cooperation rational in the first place. Emily Baldoni's character doesn't sabotage the group because she's discovered something special about her version — she sabotages it because she's done the math and understood that in a system where everyone can see everyone else's hand simultaneously, defection is the only strategy with asymmetry left.

The phone becomes irrelevant. The real weapon is certainty itself. This is why every contemporary attempt at "decentralized coordination" (Ethereum DAOs, federated identity networks, distributed DNS systems) keeps recreating this exact failure mode: the technical ability to share perfect state across a network doesn't produce cooperation — it produces a kind of paranoid stasis where every participant is running the same optimization function and arriving at the same conclusion that cheating is the only move that still matters.

The real weapon is certainty itself.

The film made this in 2013 with dinner and mirrors because the mechanics are substrate-agnostic. It works the same whether your network is a quantum-entangled universe or a blockchain with 10,000 nodes — and Coherence was accidentally documenting why perfect transparency doesn't produce trust but instead produces rational actors with nothing left to trade.