The Property of Imprecision Including the Fuzziness and the Roughness

The randomness is an objective attribute, but the fuzziness and the roughness are related to human´s cognitive activities so that are collectively known as the imprecision. The imprecision is the cost and defects which human have to bear when cognizing the uncertain objects, in detail, the fuzziness is the loss of clear understanding of a cognitive object in order to obtain the possibility and efficiency of cognition; the roughness is lack of description of a cognitive object as to be explained approximatively with two subsets of the existing knowledge set. The fuzziness is derived from the human´s classifying cognitive objects, and the roughness from the imperfection of human´s existing knowledge. The imprecision has three primary properties: subjectivity, classifying-based, and relying on existing knowledge. To decrease the imprecision should start with the existing knowledge, increasing the quantity and improving the orderliness.