PlayStation 2 Emulation Coming to PlayStation 4
How It's Done Isn't Known Just Yet
Sony confirmed to Wired via an email that PlayStation 2 emulation will be coming to PlayStation 4.
We are working on utilizing PS2 emulation technology to bring PS2 games forward to the current generation. We have nothing further to comment at this point in time.
It should be noted that in the "Star Wars" PlayStation 4 bundle comes with "Super Star Wars," "Star Wars: Racer Revenge," "Star Wars: Jedi Starfighter," and "Star Wars: Bounty Hunter." Save for "Super Star Wars," the other games have been on the PlayStation 2 at some point and are running on PlayStation 2 emulations.
Whether this emulation program is just having old games on the PlayStation 4 for sale or actually allowing you to play disc/downloads of games you own isn't known at this moment.
Source: Wired