The theory behind this move – as espoused by Ben Bernanke, first as an academic, then as a Fed governor, and eventually as Fed Chairman – is that operating on the quantity dimension of the credit cycle is the functional equivalent of acting on the price side of the equation. That supposition liberated the Fed from fear of the dreaded “zero bound” that it was approaching in 2003-2004, when, in response to the collapse of the equity bubble, it lowered its benchmark policy rate to 1%.