Are the Whites responsible for the bad things that happen to them, or are they helpless victims of fate, destined to suffer? Is it a combination of both? When we look closely at "The Monkey's Paw," it's full of questions about how much power people have over the direction of their lives.
This story is also about how we make choices. Think of Mr. White. He decides he wants to keep the paw, but it's Herbert who suggests the first wish, and Mrs. White his second one. He seems to make this second wish against his will. He knows it could be disastrous, but he does it anyway, either because he can't say no to his wife or because he wants to please her. His final wish, whatever it is, could be seen as a sign that his character is getting stronger. He is learning (rather late in the game), to take control of his life and to make good, careful choices on his own.
Fear of seeing Herbert back from the dead forces Mr. White to start making decisions on his own.
Even if Mr. White had wanted to resist the paw, he would have no choice but to wish on it.