Noriaki Iwasa (Georgetown University - Department of Government) has posted Reason Alone Cannot Issue a Universal Moral Law on SSRN. Here is the abstract:
Immanuel Kant's fundamental assumption in ethics is that morality should be autonomous, that is, reason alone must issue moral law. Examining various interpretations of Kant's moral theory, this paper shows that reason alone cannot issue a universal moral law.
G.W.F. Hegel claims that Kant's Formula of Universal Law is empty because of its lack of specific content. I point out that, among Christine Korsgaard's three interpretations of contradiction in Kant's Formula of Universal Law, the Logical Contradiction Interpretation and the Practical Contradiction Interpretation cannot identify certain immoral actions. I also show that, under certain conditions, some immoral actions pass Barbara Herman's both contradiction in conception test and contradiction in will test. Although those interpretations and tests refute what Allen Wood calls a stronger form of the emptiness charge, they are not free from a weaker form of the emptiness charge.
Next, I introduce an idea of Agrippa's trillium which plays a crucial role in the following discussions. Some philosophers try to avoid the emptiness charges in the following ways. First, some underline the roles of Kant's other formulas such as the Formulas of Humanity, Autonomy, and the Kingdom of Ends. Second, some interpret the Formula of Universal Law theologically. Third, some argue that a maxim must be something all those concerned can rationally accept. Fourth, some introduce the empirical to evaluate a maxim. Employing Agrippa's trillium, I argue that all those efforts introduce into Kant's ethics what eventually one cannot rationally justify, therefore, make his ethics heteronomous. Thus, I show that it is impossible to avoid the emptiness charges without making Kant's ethics heteronomous. On the Formula of Humanity, I also point out that it is not free from the emptiness charge. On the third response, I also show that from the fact all those concerned accept a maxim, it does not follow the maxim is true.
Thus, Kant's moral theory is either empty or heteronomous. It becomes clear that, in either event, his effort to draw a universal moral law solely from reason is a failure.
