Jack and Locke are still battling it out. As we find out more about the hatch, and more and more is still unexplained, the two characters have two very different reactions. Based on an orientation video from the Dharma Initiative (whoever they are), we find that the hatch and the computer are there to save the world from some sort of electromagnetic energy on the island. Jack goes into denial and demands answers. He won't believe what he can't explain. And Locke has faith and believes whatever the island offers, but almost blindly. Obviously both methods are flawed in a way, and these two men are going to have to compromise eventually if they are going to get anywhere, but I don't see that happening anytime soon.
Eventually we get Locke asking,
"Why is it so hard for you to believe, Jack?"
Jack seems unable to believe because he married his miracle woman and it didn't work out, it's still haunting him. He counters Locke,
"Why is it so easy for you, Locke?"
But Locke responds by saying,
"It wasn't always easy."
We find that Locke too had a hard time in his past moving on from his father, taking a leap of faith into the unknown future. But he has moved past that now and is able to believe. In this way, he is in a better place than Jack, but could still use a healthy dose of realism now and then. Unless the island demands blind faith like Locke's… I don't know.