What Tatum failed to say that night but made clear Thursday is that he is taking aim at Bird. After Tatum recorded his second triple-double of the season in a 124-104 victory over the Philadelphia 76ers, he shared his lofty ambitions. Tatum said he wants to be one of the game’s all-time greats. In Boston, he hopes to take the crown from Bird. “I’m very accomplished at a young age, but the truth is I envision myself as one of those guys: the LeBrons, the Stephs, the KDs,” Tatum said. “I want the next generation to view me as that. Wearing a Celtics uniform comes with a lot of pride, and the best Celtic ever is Larry Bird. Even if I never reach that — maybe I do, maybe I don’t — if you aspire to chase that guy, it comes with a level of focus and motivation every single day to be the best you can.”