Negative interest rate?

I was reading about a comment made by Harvard economist Gregory Mankiw in which he stated that a negative interest rate might be what is needed to avert a recession. I do not understand how that would avert a recession because it would destroy all incentive to save money and cause lending to businesses to stop completely since the negative rate would mean that you would lose the principle as a result of lending under the best terms.

What is more likely to happen is that massive inflation hits when the economy recovers, due to the printing presses being in high gear the past two years, and the Fed will be forced to raise interest rates. I would appreciate that since my I bonds have a negative real rate and CD's are getting 2% interest. At those rates, I would get better returns filling up a container of gas and then reselling it to a neighbor in a couple of months.