from Greco-Roman foundations such as the works of Aristotle and Cicero although recent work also draws from Michel Foucault, Kenneth Burke, Marxism, second-wave feminism, and cultural studies. Rhetoric has changed overtime. Fields of rhetoric and composition have grown to become more interested in alternative types of rhetoric. Critical Epistemology A critical epistemology is explicitly political and intentional with respect to its standpoint, articulating an ideology and criticizing phenomena with respect to this ideology. A critical epistemology is driven by its values and oriented to social and political change. Communication theories associated with this epistemology include deconstructionism, cultural Marxism, third-wave feminism, and resistance studies. New modes of Communication During the mid-1970's, presiding paradigm had passed in regards to the development in communication. More specifically the increase in a participatory approach which challenged studies like diffusionism which had dominated the 1950s. There is no valid reason for studying people as an aggregation of specific individuals that have their social experience unified and cancelled out with the means of allowing only the attributes of socio-economic status, age and sex, representative of the them except by assuming that the audience is a mass. Communication Theory by Perspective/Subdiscipline Approaches to theory also vary by perspective or subdiscipline. The communication theory as a field model proposed by Robert Craig has been an influential approach to breaking down the field of communication theory into perspectives, each with its own strengths, weaknesses, and trade-offs. Information Theory In information theory, communication theories examine the technical process of information exchange while typically using mathematics. This perspective on communication theory originated from the development of information theory in the early 1920s. Limited information-theoretic ideas had been developed at Bell Labs, all implicitly assuming events of equal probability. The history of information theory as a form of communication theory can be traced through a series of key papers during this time. Harry Nyquist's 1924 paper, Certain Factors Affecting Telegraph Speed, contains a theoretical section quantifying "intelligence" and the "line speed" at which it can be transmitted by a communication system. Ralph Hartley's 1928 paper, Transmission of Information, uses the word "information" as a measurable quantity, reflecting the receiver's ability to distinguish one sequence of symbols from any other. The natural unit of information was therefore the decimal digit, much later renamed the hartley in his honour as a unit or scale or measure of information. Alan Turing in 1940 used similar ideas