The upshot is that the relationship between monetary policy and financial stability is being re-evaluated. As this occurs, we seem to be moving on from the earlier, unhelpful, framing of this issue in terms of the question as to whether or not monetary policy should “prick bubbles” and whether bubbles can even be identified.
The issue is not whether something is, or is not, a bubble; that is always a subjective assessment anyway in real time. The issue is the potential for damaging financial instability when an economic expansion is accompanied by a cocktail of rising asset values, rising leverage and declining lending standards.