Simulation Hypthoesis/Theory.
Not so much the theory itself, but more some asshats who posit because some civilization could create vast/hyper accurate simulations ALA the matrix, they must and we are either in a simulation or there's a very good chance because......reasons. Elon Musk basically thinks we are definitely in a simulation because.....he's a fucking idiot who thinks he's super smart....sorry, something something probability something something.
I'm open to the idea, but so far what I've read there's no real proof nor does there appear to be any way to actually test this. Some of the proponents are pretty much "Well, we don't understand how the universe works and thus the universe we see is a simuation" which basically feels like God of the Gaps but now we're substituting the matrix for God(s). Or as someone else put it "This is religion for Atheist's". It can't be proven or falsified, it begs the quest if there is a "real" reality anywhere at all(because if we're simulated, how can we know if it's not simulated all the way down). it's true because you like the idea of it and if there's stuff science can't explain or may never be able to explain, then thus my pet theory about how of reality is an illusion MUST BE THE CORRECT ONE.