Abstract: A method and apparatus monitors well logging information obtained from a logging apparatus moveable in an earth borehole. In a disclosed embodiment, observers are established for determining the presence of specified characteristics of the logging information and generating observation-representative signals in response thereto. A knowledge base is provided, and contains a number of stored observations and stored situations which are linked by specified relationships, for responding to the observation-representative signals by computing and outputting an inference of a stored situation which is inferred from a stored observation corresponding to the observation-representative signals. In a disclosed embodiment, the knowledge base is responsive to observation-representative signals for establishing at least one confirming observer.