Lost Finale

[Trip]

Originally Posted by LeeNetworX

"The Cork" wasn't there to prevent the darkness (the spirit of Jacob's unnamed brother) from getting off the island, that job was up to Jacob and the candidates.

Did you miss the episode where Jacob tells Richard about the cork and the wine? Jacob didn't keep his brother on the island, he was there to keep the cork room safe. His brother couldn't leave because of the island's power. Jacob was there to protect the island.