One of the greatest ongoing debates in humanist communities is whether humanism is fundamentally theistic or nontheistic. Some see humanism as a more human-centered and this-worldly religious ideology. So-called “religious humanists” might believe in god or not. Many religious humanists that do not believe in god identify as religious humanists because humanism provides them with a community, a worldview, and tools of moral discernment in ways similar to traditional religions. Religious humanists that believe in god often identify humanism as a useful worldview through which to embrace humans’ responsibility for their own moral development and ethical decision-making. For many religious humanists, humanism as a worldview is not incompatible with belief in a god but rather provides all humans with useful ethical and scientific tools for better understanding the universe. The Unitarian Universalist Association contains an affiliate organization for UU Humanists, many of whom identify as religious humanists.
Other humanists dismiss the idea that humanism is a religion on the grounds that it is a worldview based on the rejection of the supernatural and the belief in the ultimacy of human potential. Some point to humanism’s lack of a set creed, rituals, and symbols in their defense of humanism as a developing worldview, rather than a religion.
Humanists who do not believe in god vary in their worldview and chosen epithet. Some humanists argue that agnosticism is the only true theological position for a humanist to hold because to prove the existence or non-existence of god is scientifically impossible. Others identify as atheists out of a belief that the evidence of the observable universe overwhelmingly points to the non-existence of a deity. Some humanists identify primarily as “freethinkers” or “skeptics.” Both terms emphasize the importance of independent rational thought and decision-making. Atheist, agnostic, freethinking, and skeptic are not discrete terms, and many humanists use them interchangeably.