關於行動理性，康德和瑟爾都宣稱，首先，人能夠基於非慾望之理由而行動，非慾望之理由具有行動的推動力。再者，人有自由意志，並且自由意志是非慾望理由之推動力的必要因素。然而康德和瑟爾對自由意志的看法相當不同，這使得他們在自由意志與非慾望理由或責任之推動力的關係方面，發展出不同的理論。瑟爾在其《行動理性》一書中比較他和康德對責任以及從事義務行為之動機的說明。他指出，他的行動理性理論能夠避免康德理論中幾個重大缺失，並且更為可信。本文首先討論康德和瑟爾對非慾望理由之構成以及其推動力之解釋。其後檢視瑟爾對康德的批評。接著本文替康德理論作出可能的辯護，指出瑟爾和康德在自由意志方面不同的詮釋。最後，在瑟爾的自由意志理論架構下，本文討論其理論之困難，並指出瑟爾在基於非慾望理由而行動之理論方面，並未成功提出比康德理論更為可信的觀點。

Both Kant and Searle argue that firstly, we can act on desire-independent reasons, and secondly, we have freedom of will; the freedom of will is indispensably related to the motivational force of desire-independent reasons. However, they have different accounts on freedom of will. Consequently they have different perspectives on the relation between free will and the motivational force of desire-independent reasons such as duty. In his Rationality in Action, Searle compares his and Kant’s accounts on duty and the motivation of dutiful actions, and he argues that his own theory is free from many problems that plague Kant's theory. In this article I will firstly discuss how we can act on desire-independent reasons according to Searle and Kant. I will also briefly examine Searle’s criticisms of Kant. Then I will discuss some possible ways to defend Kant, and make a comparison between Searle and Kant on the issue of the relation between the notion of freedom and the motivational force of dutiful actions. Finally, I will argue that Searle has difficulties explaining the motivational force of desire-independent reasons within the framework of his theory of freedom. Therefore, in this respect, his theory is no better than Kant’s.