However, the effectiveness of such targeted policies in practice is not yet proven, so the possibility that monetary policy could be used directly to support financial stability goals, at least on the margin, should not be ruled out. Conclusion The financial crisis of 2008 and 2009 will leave a lasting imprint on the theory and practice of central banking.
With respect to monetary policy, the basic principles of flexible inflation  7  The Tinbergen rule states that if the number of policy targets surpasses the number of instruments, then some targets may not be met. See Jan Tinbergen (1952), On the Theory of Economic Policy (Amsterdam: NorthHolland).