Six years ago the Federal Reserve hit rock bottom. It had been cutting the federal funds rate, the interest rate it uses to steer the economy, more or less frantically in an unsuccessful attempt to get ahead of the recession and financial crisis. But it eventually reached the point where it could cut no more, because interest rates can’t go below zero. On Dec. 16, 2008, the Fed set its interest target between 0 and 0.25 percent, where it remains to this day.

The fact that we’ve spent six years at the so-called zero lower bound is amazing and depressing. What’s even more amazing and depressing, if you ask me, is how slow our economic discourse has been to catch up with the new reality. Everything changes when the economy is at rock bottom — or, to use the term of art, in a liquidity trap (don’t ask). But for the longest time, nobody with the power to shape policy would believe it.

What do I mean by saying that everything changes? As I wrote way back when, in a rock-bottom economy “the usual rules of economic policy no longer apply: virtue becomes vice, caution is risky and prudence is folly.” Government spending doesn’t compete with private investment — it actually promotes business spending. Central bankers, who normally cultivate an image as stern inflation-fighters, need to do the exact opposite, convincing markets and investors that they will push inflation up. “Structural reform,” which usually means making it easier to cut wages, is more likely to destroy jobs than create them.

This may all sound wild and radical, but it isn’t. In fact, it’s what mainstream economic analysis says will happen once interest rates hit zero. And it’s also what history tells us. If you paid attention to the lessons of post-bubble Japan, or for that matter the U.S. economy in the 1930s, you were more or less ready for the looking-glass world of economic policy we’ve lived in since 2008.