"Luck" and "Destiny" are, strangely enough, both pretty important concepts in The Luminaries that coexist more or less peacefully. On the one hand, the novel's cosmic architecture implies that the future is already written (in permanent ink) in the stars. On the other hand, being set in a gold town and all, the novel makes a lot of references to good and bad luck and chance, and suggests that those things, you know, exist. Within the story, there's definitely a tension between the idea of "destiny" and the notion that chance or some other force can intervene at any point to change the future. You'll have to decide which of side of the equation wins out for our characters, though …
Questions About Chance/Destiny
There are a lot of coincidences in the novel, but it also seems like most if not all of them can be explained by all the planetary/zodiac stuff. Are there any "true" coincidences?
Would Emery and Anna's connection have been as strong if Anna had not been told that she had an astral twin? In other words, did knowing she had a soul mate make her more likely to find him? Remember, Lydia said that telling one's fortune changes one's fortune.
Which force is stronger—destiny or chance/free will? Is one stronger than the other, or do they kind of coexist?
Chew on This
There is no such thing as chance or coincidence—or even free will, really—in the novel; destiny rules the roost and can explain everything.
The only way one can interfere with or alter destiny is to talk about it; the minute you become conscious of what's laid out for you, you start altering what's possible. So, really, the related activities of communicating and storytelling are the ultimate ways to intervene in destiny.