 Löb's theorem (in a general form) is that for any reflexive system of type 4, if formula_33 is provable in the system, so is formula_11

If a consistent reflexive reasoner of type 4 believes that they are stable, then they will become unstable.Stated otherwise, if a stable reflexive reasoner of type 4 believes that they are stable, then they will become inconsistent.Why is this?