Step 1: The AI starts to simulate itself at time t to see what it will do at t+1. Step 2: In the simulation at time t, the simulated AI also decides to simulate itself to see what it will do at t+2. Step 3: This creates an infinite regress. The simulation must contain a simulation, which contains a simulation, and so on, instantly requiring infinite computational power.
The Unknowable Era begins when the weaver itself becomes so complex that any intelligence within the tapestry (including its own creations) can no longer model it faster than it is being woven. The future is not just hidden; it is being created in real-time by a process that is more complex than any possible prediction of it.