There is no “outside.” No other system. The universe is not on a computer. It is the computer. It is the thing performing the computation. It doesn’t need anyone watching it. It doesn’t need a server farm or a control panel. It simply is what it is: a system that processes information according to its own rules.
In other words, when we talk about the universe as a quantum computer, we’re not saying it’s pretending to be real. We’re saying this is what real is.

1:19 Reality as Code.
8:35 What Is a Quantum Computer, Anyway?
13:37 Evidence and Models That Support the Quantum Universe Idea.
20:04 What Would It Mean If the Universe Is a Quantum Computer?
26:14 Could We Simulate the Universe from Within It?
32:37 The Dark Implications.
39:53 Is This the Best Description We’ll Ever Get?