Introduction
In the logical progression of modern Western ethical thought, it is not difficult for one to discover that the early modern rationalist ethics of Kant and the modern existentialist ethics of Sartre are like two juxtaposed peaks. Each, with its own characteristics in the history of the founding of humanistic philosophy ethics and like an ongoing tradition, they echo each other even if from afar. The two moralists constructed their theories of a humanistic ethics on the cornerstone of the free subject (man), yet demonstrated different theoretical frameworks and qualities. The former raised high the banner of rationalism, establishing a set of universal principles of “practical reason” in order to enlighten and liberate humanity’s moral spirit; the latter, contemplating the significance of mankind’s actual existence, sought an interpretation of the historical conditions necessary to set up a “universal morality” for mankind.
