I have a theory: Thomas (Claire's boyfriend, aaron's father) is, actually, Ben. Ben, when younger, traveled in time (to future) and got out of the island, met Claire in Australia and got her pregnant. Evidences: His (Thomas') paintings were inside the hatch (the swan). After we know that Charles Widmore lived on the island as a young men, is easy to figure out why he have one of the paintings in his office's wall. The name of the last episode (The Little Prince) says a lot too, and the final evidence is that "the client" os that lawyer is actually Ben. It's all pretty clear to me. Is it to anyone else?