I just posted this on the first blog today, but a ton of people have responded, so I doubt people will get to my comment. Anyway, here's my theory: I believe Faraday was experiementing on himself and time traveled in the past, which is why he kept a notebook that he frequently looked at each time they time traveled. Consequently, he began losing his memory, as we saw when he talked to Widmore before going on the freighter. Therefore, time travel must effect memory somewhat. Since Jack time traveled at least once now, then he has lost a smidgit of his memory. (Claire picked out the name Aaron from nowhere, too; as well as Kate.) My only problem in this theory is the other Oceanic 6 do not recognize each other. Though do we know- aside from Sawyer seeing Kate, that they directly looked at each other when their paths crossed?