"It's the imbalance of supply and demand which causes prices to go down, but it's ultimately the valuation process of the use of the commodity...which tells you where the bottom is," Mr. Greenspan said, recalling his days trading copper a half century ago. "For example, the grain markets can have a huge excess of corn or wheat, but the price never goes to zero. It'll stabilize at some level of prices where people are willing to hold the excess inventory. We have little history, but the same thing is surely true in housing as well. We will get to the point where there will be willing holders of vacant single-family dwellings, and that will no longer act to depress the price level." I wonder if Mr. Greenspan has ever seen the inside of a vacant single family home after the heating fails or the wiring, plumbing, and HVAC gets pulled out of the walls?