Philosophy in the Public Interest, PPI, was created by Andrea Houchard, a philosophy professor at Northern Arizona University. It has become wildly successful, with forums, discussion groups, salons, etc held almost weekly in Arizona and around the country. (A forum is essentially a venue where people can come together to discuss divisive issues in a civil manner).
Andrea wanted a logo that harkened back to Ancient Greece and the roots of philosophy, that was also modern, clean and artistic. There is a series of five related sub-logos, which utilize the column image with different colors and fonts (see the 'Philosophy in the Public Interest' project), representing the various venues PPI covers.