Do we really need a pivotal supreme overseer to have a belief system? No. Not every belief system is 'theistic'. Humanism is a belief system without a supreme overseer.
Furthermore every person's supreme being is particular to that person. In addition to that an idea of supreme being that is accepted in a certain generation may not be acceptable to another generation in that community, and may be changed.
- Go on! ask yourself what does the statement "I believe in god" means?
- Does it have an objective meaning?
- One should be asked, "Which supreme being, and why?"