A theory of explanation might treat explanations in either a realist or an epistemic (that is, anti-realist) sense. A realist interpretation of explanation holds that the entities or processes an explanation posits actually exist--the explanation is a literal description of external reality.
Officers in pay grades O-1, O-2, and O-3 with more than four years of prior cumulative service in an enlisted or warrant officer grade are paid increased wages using the special pay grades of O-1E, O-2E, and O-3E, respectively.
Pay grades are used by the uniformed services of the United States to determine wages and benefits based on the corresponding military rank of a member of the services.or pay tables and information on specific pay grade wages and entitlements for members of the uniformed services, see United States military pay.