The visitor's explanation of the supposed magical powers of the monkey's paw is very brief. He says virtually everything he knows about it in one paragraph of dialogue.
"It had a spell put on it by an old fakir," said the sergeant-major, "a very holy man. He wanted to show that fate ruled people's lives, and that those who interfered with it did so to their sorrow. He put a spell on it so that three separate men could each have three wishes from it."
This seems like the author's way of getting into yet another story about a man who has three wishes and makes a hash of them. It is hard to understand how anyone could avoid having wishes or desires. Are all of these to be regarded as interfering with fate? We would end up doing nothing if we didn't try to attain at least some of our desires. The author, W. W. Jacobs, has the old fakir put his spell on a monkey's paw so that it will seem exotic to the Whites. There are no monkeys native to Britain. So at least that seems to establish part of the story, that it came from India.
If Mr. White got hold of the monkey's paw and decided to make a wish with it, wouldn't that be part of his fate in itself? Wouldn't it have been preordained by fate that he would do just that? Even if we change the scripts of our lives, couldn't it have been preordained that we would change those scripts?