If "the universe has a way of course correcting," as Mrs. Hawking tells Desmond:

1.) Why is Hawking so worried when he buys the ring? Wasn't it his destiny to be a coward and not ask Penny to marry him?
2.) Why did the Dharma Initiative work so hard to change the numbers?
3.) Why does Ben care so much about the arrival of the boat and the supposed deaths of everyone on the island?

It seems safe to assume that Hawking is right about the universe when we consider the unavoidable death of the guy in the red and white striped socks in Desmond's time travel episode and Charlie's unavoidable death; so what gives?

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"Helen, do you remember that authentic Australian walkabout I told you about?"