By discussing Kant’s practical philosophy through what could be called, according to Henry Allison’s interpretation, the human rational agency, this paper aims at approaching a potential exegetical problem concerning the relation between juridical laws and morality in the Metaphysics of Morals. Through the incorporation thesis, Allison proposes that every rational action, even those based on inclinations and desires, are to be taken, at some degree, as spontaneous, by demanding that one adopt a rule of action, i.e. imperatives in general, as a reason to act in some way. Although vital to the task of understanding desire-based actions not as merely causal consequences of inclinations, this line of interpretation apparently entails that juridical laws do not need to be based on the categorical imperative. The point is: as long as imperative-based actions in general are taken as spontaneous, merely obligation through inclinations and aversions seems to be a sufficient condition to understand what is typical of juridical laws, therefore precluding, at least apparently, the necessity to appeal to a categorical imperative that is known to found Kantian morality by demanding an action to be taken as a duty by itself.