Description du poste
The Arrow information paradox (AIP) says there's no ideal way for a potential buyer to determine the value (to them) of some private information a seller is offering to sell them, without actually receiving the information, thus jumping the gun on the potential trade.
The paradox happens because a sale of information is:
• Irreversible: the information can't be "returned" like a physical good, once the cat's out of the bag• Indivisible: there's no sense in which "half a secret" can be half as valuable as the whole secretIn other words, if you're considering buying a huge amount of wine but you don't know the quality, you can sample a random bottle of the wine, and if the connoisseur who works for you says it's good you buy the whole lot. But if the thing you're considering buying is One Big Important Secret, you couldn't do something like this (at least in the pre-LLM era).
Of course, the way this has been dealt with in practice is NDAs. And patents I guess. But these only go so far, since they depend on a government to enforce the NDAs, and there have been exceptions where people broke NDAs for arguably justified reasons, e.g. whistleblowers. So in some cases the seller would still prefer to enforce the privacy by technical rather than legal means.
Why, fundamentally, has the AIP held? It's because (until recently) there has been no evaluator able to both:
• Understand the secret information and make qualitative judgements about its value, in the buyer's specific context• Credibly forget everything about the secret information (or alternatively just vanish, removing the need for "forgetting")Human evaluators can understand and exercise judgement but can't forget; cryptography (zero-knowledge proofs, confidential computing, etc.) can forget but can't judge.
Now, of course, over a billion people use competent agents—who can incorporate arbitrary context and make reliable qualitative judgements—on a weekly basis. These agents are also ephemeral, so you can get privacy