The will

I.I. The faculty of desire In the Second Section of the Groundwork, Kant undertakes a properly philosophical search for the principle of morality. “Everything in nature,” he says, “works in accordance with laws. Only a rational being has the capacity to act in accordance with the representation of laws” – a capacity Kant characterizes as will and directly equates with “practical reason” (G 4:412). Behind these claims lies a theory of the will that Kant tended to take for granted but soon found it necessary to explain a bit more fully in response to bewildered critics (KpV 5:9; cf. MS 6:211–214).

Kant divides the mind's powers into three basic ones: the faculty of cognition, feeling (of pleasure and displeasure), and the faculty of desire (KU 5:198). These powers typically work together. It is especially true in the case of the faculty of desire that it operates only in concert with both cognition and feeling. Kant defines the faculty of desire (Begehrungsvermögen) as the capacity to produce an object (or state of affairs) by means of a representation (Vorstellung) of that object (KpV 5:9, MS 6:211). To desire an object (or state of affairs) is to have a representation of it accompanied by a feeling of pleasure. (Aversion is a representation accompanied by a feeling of displeasure.) Desire may or may not involve an awareness of our capacity to produce the object.