 Fred Dretske’s 1981 Knowledge and the Flow of Information offered a much expanded treatment of a type of causal theory. Rather than basing semantic content on a causal connection per se, Dretske began with a type of informational connection derived from the mathematical theory of information. This has led some to refer to Dretske’s theory as “information semantics”. Dretske also appealed to the notion of function in an attempt to distinguish content determining causes from adventitious non-content determining causes. This has led some to refer to Dretske’s theory as a “teleoinformational” theory or a “teleosemantic” theory. Dretske’s 1988 book, Explaining Behavior, further refined his earlier treatment.