Abstract

Kant's moral constructivism and Rawls's moral constructivism is generally agreed that use of the standard, the standard to prove the effectiveness of their moral principles and the principles of justice, they all belong to the obligation on the parties, the categorical imperative and the principle of justice also has a similar of. However, Kant's metaphysical construction of the subject, while Rawls's construction of the main characteristics is not a metaphysical; Kant's constructivism is constituted of self-discipline, and Rawls's theory of self-belonging; construct their own out of principle with a different scope. Rawls changes that weakened the power of the principles of justice, in the post-metaphysical conditions, Habermas's understanding of moral objectivity can provide a solution ideas. Both Kant's and Rawls's constructivisms have used the standards of universal agreement and validity to demonstrate their moral principles and justice principles respectively; Both constructivisms belong to deontology; Kant's categorical imperatives and Rawls's justice principles resemble each other in a way too. However, Kant's constructive subjects are metaphysical, whereas Rawls's are not; Kant's constructivism belongs to constitutive autonomy, whereas Rawls's belongs to doctrinal autonomy; In addtion, their principles apply to different fields. Rawls's transformation weakens the persuasiveness of justice principles and Habermas' viewpoints provide a solution for moral objectivity under post-metaphysical conditions