Success: How much is due to effort, and how much to luck?

This is an interesting discussion thread about how success depends not just on our own efforts, but on luck, too — especially in our choices of parents and of upbringing — and so we ought to have plenty of sympathy for those who come up short in the luck category. Excerpt: "When once asked for the secret of financial success, he [the Duke of Westminster] replied it was to have an ancestor who had been a close friend of William the Conqueror."