In the second chapter of the second Critique, Kant explicitly addresses three questions: (1) What is the object of practical reason? (5:57–65) (2) What are the categories through which practical reason determines this object? (5:65–67) (3) How does the faculty of practical judgement mediate between action and the moral law? (5:67–68) As a response to these questions, Kant develops a theory of ethical judgement for assessing the unconditionally binding character of the claim to validity that is raised by any moral judgement. He attempts to determine both whether this claim can be justified and how it can be rendered practically effective.

The Object of Practical Reason

Kant defines the object of practical reason, as distinct from the cognitive object of theoretical reason, as an envisaged consequence of an act of freedom. Such an object is not something already given, like a natural object, but something which must first be brought into existence through a specific kind of act. The constituting conditions for such a thing lie within the faculty that initiates the production of ethically relevant objects – namely, the will itself.

The will does not automatically heed the prescriptions of practical reason, but can also be determined by non-rational factors (by feelingsc of pleasure and displeasure, or by objects that are agreeable or useful) to which it may accord priority over such prescriptions.