Evidential Cooperation in Large worlds (ECL) refers to the idea that, since the universe may be very large, it likely contains many agents very similar to oneself, and that by taking actions that are good for these agents, we learn that they take actions that are good for us. The idea of ECL was introduced in Oesterheld, 2017 as MSR (Multiverse-wide superationality).

Further Reading

Caspar Oesterheld (2017): Multiverse-wide Cooperation via Correlated Decision Making

Caspar Oesterheld (2017): Multiverse wide Cooperation via Correlated Decision Making. Talk at EA Global London.

Johannes Treutlein (2023): Modeling Evidential Cooperation in Large Worlds

Lukas Finnveden (2023): ECL with AI

Various writings: https://longtermrisk.org/ecl