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This paper examines the definition and origin of complexity from the methodological angle and try to illustrates that there are objective grounds for the distinction between simplicity and complexity，that can’t be ascribed to subjective reasons.By these arguments, this paper claims that science of complexity has its objective of research，research on complexity should follow a methodological rule of "taking the complexity as complexity to deol With.”<br/>

Ling一Chao Tsien(Qian Linzhao，1906一1999)was a famous Chinese physicist . He had made significant contributions to the development of the researches on plastic deformation of crystals, electron microscopy and history of science .His work laid the foundation of these research fields in China .This article gives an account of his life and his scientific work.<br/>