The Cosmic Zoo Hypothesis: Silence, METI, and the Fermi Paradox

To the point

John Ball’s zoo hypothesis says advanced extraterrestrials quietly watch Earth from a cosmic zoo and don’t interfere, letting humanity evolve and explaining the lack of detectable alien signals while fueling debates about METI, though critics doubt such galaxy-wide restraint is plausible and warn of the risks of broadcasting.

Zoo hypothesis may explain why we havent seen any space aliens
nbcnews.com

Zoo hypothesis may explain why we havent seen any space aliens

The hypothesis holds that they can see us, but we cant see them.