Nontheism is when you do not belief that any god exists. _______________ It seems not to be a very good comparison. It is like asking "What is the difference between fans of baseball and people who are not fans of baseball? Isn't there only the one obvious difference and no other? Fans of baseball really like baseball. Monotheism is belief in one deity. Nontheism is not a coherent, unified belief of any kind, as is monotheism.