What is essential to acting morally is not fulfilling some rule about outward appearances, but rather being motivated in the right way, that is, by the motive of duty. There is no way that we can explain this motive further, for it is equivalent to causation from the noumenal world, and none of our concepts are applicable to that world. We can, though, talk about the effect of the moral motive on the rest of our psychology.
We humans are naturally inclined to follow self-love, that is, to strive to please ourselves by satisfying our desires. We are also inclined to self- conceit, to thinking that just by virtue of being oneself one is at the center of the universe and deserves to do whatever one pleases. The moral law strikes down these feelings, making us aware that we cannot do whatever we please. We also feel pain when the moral law forces us to leave our desires unsatisfied. On the other hand, the strength of the moral law to overcome our desires awakens respect for it. This combination of personal humiliation and respect for the law is the peculiarly moral feeling. However, this moral feeling is not the incentive to act morally but rather only the accompaniment of acting morally, for only the idea of duty can be the right motivation.
Respect, in particular, is a distinctively moral feeling. All sorts of things, ranging from talented people to majestic mountains can produce the similar feelings of awe and admiration. But only the operation of the moral law can produce respect. We see this when we think first of the talented but morally bad person and then of the humble but morally upright person. We feel admiration for the first person but no respect, while we cannot help but respect the latter, even if we might rather affect an air of superiority.
The correct incentive is obedience to the moral law, and not love of the moral law. For to act morally because we like to is to make one's adherence to the moral depend on one's continued liking of it and continued pleasure at satisfying it, which is not consistent with true morality. God's will is a "holy will," which naturally follows the moral law. Since God has no urges to disobey the moral law, it is not even really a law for him. This is not true for humans, though, and it is arrogant to act as though it was. We must therefore be prepared to obey the law no matter how we feel about it.
This sort of action is free, undetermined by empirical incentives and caused noumenally. What then of the theories that we can understand freedom in terms of this world? They have a general flaw, in that this world is a series of events with later events caused by the earlier. My physical state, which supposedly freely causes an action, is the result of the distant past over which I have no control. So if the physical world was all there is, the action would be caused by the past that I cannot control, and it would be outside my control. My freedom would at best be like the freedom of a clock that can follow its mechanisms without interference once it has been wound. However, since the human being exists also in the noumenal world, there can be real freedom. Even if my present actions are caused by the past, if I exist outside time, I could have created the whole sequence of events differently. This is why it makes sense to repent for past bad deeds, and why we place moral blame even on those whose character is unchangeably bad.
Investigation into the moral leads us to see the value of recognizing a distinction between the phenomenal and the noumenal, with space and time adhering to the phenomenal and freedom requiring the noumenal. These are the same results as those of the independent investigations of the first Critique, and so the first and the second Critiques lend each other support.
Kant's argument that we must act in obedience to morality and not out of love of morality is much like his argument that the moral law must not contain any matter over and above its form. In both cases, the problem with the rejected alternative is that it makes adherence to the moral law depend on one's contingent desires. In both cases, the argument itself is problematic. It is true that in acting morally out of love, one's moral actions will stop if one's love stops. But then if one acts morally out of duty, one's moral actions will stop if one's dutifulness stops. Kant is only left with the complaint that if one acts out of love, this ultimately rests on the faculty of self-love and its pursuit of the pleasure of satisfying one's love of morality. The idea would be that pleasure and self-love are always self-evidently anti-morality and frivolous. But that cannot be taken for granted.
Let us look at Kant's account of how it feels to act morally. There is certainly a grain of truth in the idea that the feelings accompanying it are, on one hand, disappointment at one's unsatisfied conflicting desires that one must lay aside and shame at not being able to do away with them, and, on the other, a feeling of elevation at being called by a higher purpose. However, it would be going too far to say that we always feel like this, or even that this is the way that acting morally usually feels. For one thing, this seems very much the description of someone who acts morally with great reluctance. His desires conflict with his duty and continue to nag at him, leaving him feeling not only conflicted but also humiliated. Kant explains this humiliation as stemming from the combination of the human urge to see oneself as the center of the universe and the moral insight that one is not. This is a real phenomenon but, for a healthy person, is far from the accompaniment of every moral act.
Sometimes, it seems that the moral act is quite different. One sees a situation that calls for action—for instance, when a child is being harassed by a bully. Seeing what is wrong and that you can help motivates you to act, in this case, to drive the bully away. One's feelings are focused more on the situation at hand (pity for the child, anger at the bully) and not so much on one's overall moral unworthiness or respect for the abstract idea of the moral law. One may or may not feel conflicted by non-moral desires that are going unsatisfied, like the desire to get about one's own business or to avoid danger. Often conflicted desires are simply set-aside for the moment. Nor does the moral person always need to be filled with self-loathing simply because he has conflicting desires—if a person felt a twinge of annoyance at falling behind schedule before helping the child, this hardly calls for anger at himself.
Kant's theory of freedom is original but also difficult. Once we are trapped into explaining how we can be free and yet also be determined by a causal series stretching far into the past, Kant's solution gains credibility by a lack of better alternatives. But it is hard even to grasp how "I" can be both the person whose experiences are in time and whose actions are determined, as well as the unknowable noumenal person who is creating the whole sequence of appearances. There is also the question of how multiple people can be free. How can I be creating the appearances of the whole determined world while you are doing it at the same time? It is possible that Kant would imagine the creation of the temporal universe as a collaborative project between noumenal selves, each of whose freedom is absolute and yet a constraint to the project as a whole.