Of the interest attaching to the ideas of morality
In the present section Kant discusses a topic in some way related to the “Reciprocity Thesis”, i.e. in which sense the conceptual presupposition of freedom as autonomy might serve to validate the moral law. What is at stake is the nature of the “validity” or “practical necessity” of the moral law, which must be kept distinct from the problem of the “bindingness” or “practical reality” discussed in the following section suitably titled “How is the Categorical Imperative possible?” (G453-455).
G 449-450 (§§1-4 of the section)
After having achieved the “determinate concept of morality” through the presupposition of the “idea of freedom”, Kant proceeds along the path of the justification of the supreme principle of morality (which has already been elucidated in Section Two). Kant says that so far we have presupposed: (1) the ”idea of freedom”, not freedom as such, as a condition of possessing a rational will, which it could be referred to as the capacity to judge or to make freely choices accompanied by the consciousness of its causality, and (2) that we are entitled to lend this character of rational will to all rational agents.
But then Kant adds a somewhat awkward question introduced by an equal obscure reference to the objective validity of maxims. Let’s examine the statement on maxims first.
But there also flowed from the presupposition of this idea consciousness of a law for acting: that subjective principles of actions, that is, maxims, must always be so adopted that they can also hold as objective, that is, hold universally as principles, and so serve for our own giving of universal laws. (G 449).
The problem here is not with the explicit meaning of the paragraph, which is clear enough; the obscurity derives from its collocation. Why Kant decided to put it there? This passage seems to me to be referred to a previous requirement, although not explicitly stated by Kant, concerning the knowledge of the Categorical Imperative, say, the presence of it to the agent's conscience. By presupposing freedom and our way of thinking of ourselves as subjected to it, we experience the law of autonomy, that is, that our maxims should be adopted as universal laws valid for every being “endowed with reason” (G 449). How should we understand that experience? The point becomes particularly intriguing in the light of the query:
...why, then, ought I to subject myself to this principle and do so simply as a rational being, thus also subjecting to it all other beings endowed with reason?” (G 449).
How this question is related to the previous discourse about freedom? It is hard to pin down precisely what Kant takes this to involve.
A possible answer, but of the wrong kind, would be to refer to “an impulse” or interest pressing the agent to comply. However, if we presuppose freedom we cannot possibly rely on impulses. The principle we are already committed to by accepting freedom is clearly the principle of autonomy, which rules out any kind of interference coming from the sensibility. For this reason, Kant suggests that we should talk of “taking an interest” (in the principle of morality) instead of having an interest pressed by an impulse. The meaning of this new expression is related to the distinction between the two standpoints Kant is going to make in the subsequent paragraphs of the section.
Before we are able to deal with it we need to confront with the problem of the “circle”: