System theory, information theory and cybernetics call it "the third theory". These three theories are derived from biological science, communication science and automation science respectively. Dissipative structure theory, synergy theory and catastrophe theory are called "new three theories" These three theories originated from thermodynamics, physics and mathematics respectively, and are widely used in many natural and social sciences. Ontology, three-world theory and small-world phenomenon are called "cognitive three theories"

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information theory

Information theory takes the model of communication system as the object, and uses probability theory and mathematical statistics as tools to describe the problem of information transmission and extraction from quantitative aspects. The research field of information theory has been extended to mechanical, biological, social and other systems, and has developed into a science that uses mathematical methods to study the general laws of how to measure, extract, transform, transmit, store and control information of various systems.

cybernetics

Cybernetics uses the concepts of information and feedback to study the state, function and behavior of the system by means of black box system identification and function simulation, and adjusts and controls the system to achieve the goal stably and optimally. Cybernetics fully embodies the development trend of modern scientific integration and has very important methodological significance.

system theory

System theory uses the concepts of wholeness, centralization, hierarchical structure, finality and logical isomorphism to study the modes, principles and laws applicable to all integrated systems or subsystems, and tries to describe their structures and functions by mathematical methods. The system emphasizes the organic connection between the whole and parts, parts and parts, and the whole and the external environment, and has three basic characteristics: integrity, dynamics and purpose. As a guiding ideology, system theory requires that things be regarded as a whole or a system, which is in line with Marxist philosophical principle of universal connection of the material world.