Diamond-encrusted, alligator-skin handbags. Eighteen-course feasts. Yachts the length of city blocks. In the twenty-first century, many point to such conspicuous consumption as reflecting the moral failings of a rampant capitalism that sacrifices community values on an altar of greed. Television shows such as Keeping Up with the Kardashians illustrate the folly of wealth without responsibility even as they elevate their subjects on pedestals of desire. Our discomfort with extravagance is not new. The ancient Greeks and Romans fretted over the ideal relationship between morality and...