In your ruminations about the nature of wealth, where you distinguish between financial and real wealth for the benefit of a visiting Martian, you point out that housing is more complicated than the stockmarket because homes are both consumption and investment goods (“The Nature of Wealth,” October 10, 2009). Indeed. People get utility from living in their homes while thinking of them as assets to be sold in the future. The dual nature of homes can thus get quite confusing. You argue that a rise of house prices that outpaces the growth of an economy does not make a society richer: “all that is achieved is a transfer of wealth from first-time buyers to retirees exiting the property market.” However, a strong rise of house prices can and usually does lead to second and even third mortgages, which are often used for the purchase of second homes, frequently in connection with retirement to come. In such cases, price increases have real effects that do impinge upon the wealth of society. Much of the housing bubble leading up to the current economic crisis was especially confusing because the oldest among baby-boomers were contemplating retirement precisely in this period. The second or third mortgage came handy in the purchase of the second home, which was to become the only home after the sale of the mortgaged property. Although the crisis has affected the price of second homes, as well, their utility has not been affected at all. A Martian contemplating such earthly wonders would surely be perplexed no end.