Something Wicked This Way Comes considers the various aspects of acceptance. Bradbury suggests that the ability to accept oneself is not simply a trait that people have; it is a quality that people must develop. Charles Halloway is not a happy man, but that is not really all that important. What is important is that at the beginning of the book he does not accept himself. His fifty-four years drag on him, and he is not sure of himself as a father. But at the critical moment in the book, when the Witch is about to stop his heart, he suddenly looks up and realizes that there is no need to be afraid of what he is or is not. Charles Halloway understands that he is simply a man who must go about his life and he finally comprehends that we cannot change what we are—but we can become comfortable with it and go from there. Once he accepts himself he laughs the Witch out of the library and then, sure in his heart, he moves on to the carnival where he quickly dispatches the Witch, the Mirror Maze, and Mr. Dark. His acceptance allows him to see the carnival for what it is, something that feeds off of people who are unhappy with who they are.
Similarly, Jim has to accept who he is. He spends most of the book chasing something that will destroy him simply because he does not want to stop chasing. Jim needs to ride on the carousel because he wanted to when he first thought about it and he cannot stand the thought that he will be stopped from doing something that he wants to do. This is not egotism on Jim's part; he simply does not want his freedom curbed. But he has to learn that being a human being means you do not have unlimited freedom. Will sacrifices much to help Jim, and Jim needs to learn what it means to have friends. It appears by the end of the book that Jim accepts himself and knows that what he desired all along, to ride on the carousel, would not be good for him.
The idea of common cause is put forth by Charles Halloway as his reason for why people are kind to each other. When you believe that you have something in common with someone else then you are willing to do things that you would not otherwise be willing to do. But Halloway's notion goes deeper than that, since he argues that all people share one fundamental commonality: specifically, we are all going to die. If we use that commonality to allow us to gain some sort of common ground with which to view everyone around us then the world will be a better place. Charles Halloway sees that common cause is the root of extending a relationship to another human being and he thinks that if all human beings had at least a minimal understanding of each other then evil would fall on hard times. For evil like that of the carnival preys upon those who are isolated and feel that no one understands their desires or cares about them. But if people saw everyone as players in the same game there would not be such isolated ones, and they would have something to go to besides the bright but empty allure of the carnival.
Age is also an important theme in this novel. Charles Halloway learns that what matters is not the number of years that one has been alive but the feeling that one has, the love for life that one exhibits. If you are young at heart and desire only to run like a younger boy then you may do so, even at age fifty-four. At the same time, Mr. Cooger and the carousel shows us that physical age cannot be trusted; it is mental age that is important. The only age that matters is whether the mind is young or old, quick or slow. Jim does not understand this point early in the novel, only learning it at the very end. It does not matter if your body is twenty-five years old and your mind is only 13. You will still be a thirteen year old. And even the number of years you have lived does not necessarily reflect your mental or physical age. Jim, at thirteen, has twenty years of looking at the world. Will has only six. But then Will probably has more years pondering things than Jim does. Viewing age from so many different perspectives in some degree dissolves the concept of age.