Right now, all news we have about the PS4 is rumor, speculation, fannish hope, and a leaked photo of a controller that may or may not be a prototype. But one can logically conclude that Sony will be offering backward compatibility of PS3 titles on their PS4—and not just because the company purchased the cloud-streaming service, Gaikai, for $380 million in 2012 or a paywalled report in the Wall Street Journal. It’s because of Sony’s “Evolution of PlayStation” video series.