A nonbeliever is a person who lacks a belief in a certain claim. Nonbelievers say that opinions should be formed on the basis of science, logic, and reason, and should not be influenced by authority, tradition, or other dogmas. Nonbelievers tend to have logic-seeking personalities and are unable to believe in anything that is not supported by evidence. Nonbelievers may question religious doctrine, but are not necessarily antireligious.
Socrates was one of the first nonbelievers of whom we have records; he questioned the legitimacy of the beliefs of his time in the existence of the various gods.