This is just something I thought of while watching the season premiere.
Shouldn't alternate Locke be dead? Assuming everything happened the way it did before with his father (and there is nothing at this point to suggest that it did not), then Locke fell out the window.
But wait a minute. Jacob's not sitting on that bench. His hut, the statue foot, the whole island, they're all underwater. Why would he need to visit anyone now that there's no island to go too? And though this is still speculation, doesn't it appear that when Jacob touched Locke, he seemed to come back to life? Without Jacob, Locke died on impact, without anyone to revive him.
This is probably a completely flawed analysis and I'll have to move to Jurassic Park to atone for this, but tell me what you think anyway.