Abstract: The modern Chinese ethical enlightenment is a process of reconstructing ethical concepts under the guidance of the idea of advocating rationality and opposing authoritarian superstition. Along with eastward transmission of western culture and science, there was a huge tension between Chinese tradition and modernization. Science had its pursuit “evidence” and “truth”, a feature which distinguished it from traditional Chinese culture that accepted the transcendental “Li”. Science was therefore gradually endowed with the significance of ethical enlightenment. The Ethical Enlightenment Movement in the May 4th Period shook the ontological basis on which traditional ethics depended. Thanks to that, “science” became the criterion of rationality of new ethical concepts and evolved into “scientism”. Although science can not replace ethics, and “pure rationality” can not be the alternative of “practical rationality”, the scientific spirit advocated by the slogan “science” has enabled Chinese people to gradually step out of the mode of thinking of experience and intuition, serving a role of enlightenment.

Key words: ethical enlightenment, science, tradition, the struggle between science and tradition