What does Amir's dream of Baba fighting the bear mean??

Early in the novel, as we're getting to know Baba, Amir relates one of the legends about his father. Apparently Baba wrestled a black bear in Baluchistan and has the scars to prove it. Now, we know what you're thinking: no one could wrestle a bear and live to tell the tale. But Amir reassures us this story isn't typical Afghan laaf (exaggeration). The story has obviously affected Amir because he imagines it "countless times" and even dreams about it (3.1). And here's the interesting part. In his dreams, Amir can't tell Baba apart from the bear.