In a few breathtaking months, we\u2019ve culturally moved from seeing Wall Street as an icon of thriving civil society to discussing its workings with book titles like \u201cHouse of Cards\u201d and \u201cAnimal Spirits.\u201d As part of our ongoing Repossessing Virtue series, we look at what science is learning about trust, fair play, and empathy \u2014 and what these qualities have to do with human character and economics.