“Help me understand: how do multiverse acausal trades work?” by Aram Ebtekar

While I'm intrigued by the idea of acausal trading, I confess that so far I fail to see how they make sense in practice. Here I share my (unpolished) musings, in the hopes that someone can point me to a stronger (mathematically rigorous?) defense of the idea. Specifically, I've heard the claim that AI Safety should consider acausal trades over a Tegmarkian multiverse, and I want to know if there is any validity to this.

Basically, I in Universe A want to trade with some agent that I imagine to live in some other Universe B, who similarly imagines me. Suppose I really like the idea of filling the multiverse with triangles. Then maybe I can do something in A that this agent likes; in return, it goes on to make triangles in B.

Problem 1: There's no Darwinian selective pressure to favor agents who engage in acausal trades. [...]

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First published:
September 1st, 2025

Source:
https://www.lesswrong.com/posts/BxfscrfGJPq5Yxfit/help-me-understand-how-do-multiverse-acausal-trades-work

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Narrated by TYPE III AUDIO.