Zhungzi criticized Confucian ethics based on the Heaven. From the perspective of the Heavenly Way, Confucianism and Mohism have equal values, and cannot claim superiority over their counterpart. Xunzi accepted his criticism and broke the connection between the Heaven and Confucian ethics. Xunzi also did not suppose ethics on the basis of human nature in considering human nature is bad. Xunzi shifted his focus on an essential aspect of the ritual in order to justify the objectivity of Confucian ethics, that is, a categorical aspect of the ritual. In his theory, the ritual is defined as the collection of categories of things. The most important function of the ritual is to divide, which is accomplished by human action of categorization. According to the chapter "Rectifying Names," naming is based on categorization and the action of categorization has two traits, natural and conventional. We categorize things with the help of our cognition, which is separate from our capacity for language, and at the same time do so out of convention. The naturalness of categorization ensures the objectivity of norms. Our categorization from convention changes because of the influence of society and culture, and differs in individuals and cultures. Xunzi revealed the idea of value pluralism in his concept of a 'guiding principle'. He held that if we put categorization to the extreme, we will realize the guiding principle for dealing with affairs. We are able to know it only by practicing the institutions and laws of our former kings. That is, we will know the guiding principle only by learning and practicing the carefully selected experience of former generations. It is the wisdom we can acquire by learning historical experience and objectifying them. Therefore, the guiding principle does not have an absolute foundation. In addition, the ritual, which is another name for the guiding principle, cannot be regarded as absolute and universal, but has the commonality and stability as long as it is related to human experience.