Rational beings have the unique capacity to cause events through free will. Since a will that is free must be a will that gives itself its own law, autonomy of the will and free will are one and the same. Thus a will is free when and only when it follows moral laws. Morality therefore follows from the concept of free will.
Since morality is a matter for all rational beings, not just human beings, we cannot base our notion of morality on the concept of free will unless we establish that all rational beings have free will. "Proving" this issue from experience would be difficult if not impossible, yet we may assume that a being really is free if it thinks of itself as free when it acts, for such a being must be aware of morality's demands whether or not it really is free to execute them. Moreover, any being endowed with reason and with a will must think of itself as free, for reason would not be reason if it were subject to control by irrational forces from outside itself.
Thus we may presuppose that rational beings think of themselves as free, and we have established that the moral law and the categorical imperative follow from this concept of freedom. Yet why we would want to abide by this law is a different question. We may want to be moral because we feel it makes us more deserving of future happiness, yet this is merely an expression for the value that we attribute to morality; it does not answer the question of why we value morality.
Our logic so far seems circular: we explained that we may think of ourselves as free because we are aware of moral demands, yet on the other hand we based our notion of morality on our concept of freedom. This problem may be resolved by drawing a distinction between "appearances" and "things in themselves." In our everyday experience, we encounter a "sensible world" of appearances. We may presume that these appearances come from real objects ("things in themselves"), but we can have knowledge of these objects only insofar as they affect us. Human beings make use of the faculty of "understanding" to make sense of the world of appearances. The faculty of reason distinguishes between the "sensible" world of appearances and experiences, which will be different for all individuals, and the "intelligible" world of concepts that make sense to all people. Reason may also recognize the limits of understanding.
Human beings may understand themselves from the perspective of either the sensible or the intelligible world: they may think of themselves in terms of either the laws of nature, or the laws of reason. Insofar as rational beings think of themselves in terms of the laws of reason, they understand themselves to possess a free will that is independent of the forces of nature that govern the sensible world. This idea of freedom is the basis for the concept of autonomy and the moral law. Thus our inferences are not circular: our concept of freedom does not depend on our notion of morality; rather, it may be derived from our participation in the intelligible world.
If people lived exclusively in the intelligible world, they would possess a perfectly free and autonomous will. On the other hand, if people lived exclusively in the sensible world, all their actions would be governed by the law of nature and the rules of cause and effect. When actions of the will enter the sensible world, they have to be understood in terms of the rules of cause and effect that govern that world; thus actions will appear to have been caused by material needs and inclinations. Nevertheless, as rational beings we know that the intelligible world is the primary world for us; it is the "ground" for the sensible world, for we know of our sensible self only through appearances, whereas we have immediate knowledge of our intelligible self. We therefore know that we are subject to the categorical imperative and the ideas of freedom and morality that are entailed by the intelligible world.
If we lived exclusively in the intelligible world, the categorical imperative would command our will automatically. As it is, the categorical imperative takes the form of an "ought": all of us--even the most rotten scoundrels--know that we ought to have a pure will, even though in practice we cannot avoid impure influences.
Our idea of freedom is an a priori concept: it cannot be given to us by experience, for all our experiences are governed by the causal rules of the law of nature. On the other hand, our idea of natural necessity is also an a priori concept: the notion that all events are caused by prior events is a concept that we use to make sense of the world of appearances. These two concepts form an "antinomy"; neither concept can be explained away, and the contradiction between them cannot be resolved. We may recognize that each is appropriate for different purposes: we use the concept of necessity when we seek understanding, and the concept of freedom when we are pursuing a course of action. It is not necessary to decide which concept is correct. Things as appearances are governed by necessity; as a thing in itself, we are free. This duality is an inevitable consequence of the fact that we are divided between sensible and intelligible worlds.
All that individuals may know of the intelligible world is that reason demands that they act according to its law. The intelligible world cannot provide concrete objectives for action. Rather, it provides only the requirement that actions must follow a maxim that could be a universal law, and which is therefore consistent with freedom and autonomy.
Reason cannot demonstrate that we are free or prove that morality is possible, for whenever we use our intelligence to understand the world we cannot help but think in terms of the cause-and-effect relationships that govern the sensible world. The most reason can show is that the fact that causality governs the world of appearances does not mean that we cannot be free as things in ourselves. Reason also cannot explain why behaving morally makes us feel good. All that we can know is that morality is not based on this feeling, for this feeling is an experience; basing our moral sense on an experience would be heteronomy, whereas morality requires autonomy. Thus the idea of freedom is the only support that reason can provide for morality and the categorical imperative.
When reason seeks knowledge, it can do so only by determining the necessary conditions under which something is possible. This process produces an infinite regress: one thing is possible because of certain conditions, which are possible because of certain conditions and so forth. Reason escapes from this infinity by seeking unconditional imperatives. Consequently, it is not bothered that it cannot provide an explanation for the unconditional imperatives that it receives from morality and the idea of freedom. Indeed, if reason could provide a conditional explanation for our freedom, it would not be freedom, for freedom must be unconditional. It is enough for us to recognize the limits of our understanding and acknowledge the implications of the idea of freedom that we inexplicably possess.
At first glance, Kant's analysis of freedom may seem strange. It certainly seems paradoxical to suggest that we are truly free only when we submit obediently to the moral law. Most of us probably think of ourselves as most free when we are at our most spontaneous--we feel most free when we do what we want to do. Kant's notion of freedom, however, is rigidly disciplinarian: you are most free when you follow the moral law and abide by reason's universal demands. The freedom of "doing what you want to do" is an illusion because when you do what you want to do you are a slave to physical needs and desires that come from your nature or the world around you, not from your capacity to give yourself your own law.
Historically speaking, this notion of freedom has more than a little to do with Kant's Protestant Christian heritage. In Kant's philosophy, a secular notion of reason has replaced God, but the hierarchy is fundamentally the same: spirit is good, body is bad; people are free when they follow spiritual strictures and suppress bodily desires.
Yet the fact that Kant's ideas have an identifiable pedigree does not mean that they are wrong, so it is important to evaluate Kant's argument carefully. Kant himself admits that, at first glance, there appears to be no good reason why we should follow the demands of reason and morality rather than the other demands of our nature. He thinks, however, that the distinction between appearances and "things in themselves" can provide some insight into why we attribute a higher value to morality and free will than to bodily needs and desires.
This distinction should be familiar from the Context section. According to Kant, we can have knowledge about the world only insofar as the world interacts with us. Thus we have knowledge only of "appearances," not of the "things in themselves" that actually make up the world. This division applies to ourselves as much as it does to other objects of our experience. On the one hand, we have a sensuous experience of ourselves as physical beings influenced by material interests and desires. On the other hand, we are aware that this physical self and the world of appearances in which it participates is not the whole story: we are also aware of an "intelligible" world including a concept of freedom.
Kant shows that this concept of freedom provides a basis for the notion of morality that he has developed in the Grounding. Being free, he argues, must mean being able to give ourselves our own law. Our law would not be our own if it came from conditions that we cannot control. Thus, Kant concludes, being free must mean pursuing a course of action that has unconditional validity--that is, validity independent of our life's material conditions. Recall that this requirement of unconditional validity was Kant's starting point in his analysis of morality: Kant began from the assumption that moral actions are actions which are undertaken for the sake of duty alone, rather than for the sake of some concrete objective. Since the requirement of unconditional validity led to the moral law and the categorical imperative, the idea of freedom must lead there also. Our idea of freedom provides a basis--a "ground"- -for morality.
Kant stresses, however, that a logical basis is different from an explanation. Knowing that freedom provides a basis for morality is not the same as knowing why we want to be moral. Likewise, knowing that we have a concept of freedom is not the same as knowing that we are free. Indeed, according to Kant, rational analysis can never prove that we are free, for any time we analyze our decisions we will see that certain circumstances or influences may have caused us to act as we did.
Yet if reason cannot prove that we are free, it can at least show that our idea of freedom cannot be disproven. This move in Kant's argument is the essential twist of Kant's "Copernican Revolution": when reason is caught in a bind, when analysis cannot resolve an issue (in this case, the issue of whether we are free), Kant turns reason back against itself, performing a "critique" of reason that demonstrates the limits of our understanding. We cannot know that we are free, yet we equally cannot know that we are not free. The fact that every event may be explained by a prior event is a quality of the world of appearances; it is a feature of the picture of the world that we develop as we go about trying to make sense of our experiences. It is not necessarily a quality of things in themselves. Since we are things in ourselves, causal determinacy is not the final word for us. Our notion that we are free may be correct, appearances notwithstanding.
This argument still does not explain why we would want to go about maximizing our freedom by following the categorical imperative and seeking autonomy. Kant presents three suggestions as to why we might value our freedom so highly. First, he points out that moral behavior makes us feel good--that we feel good about ourselves when we "do the right thing." He notes, however, that this feeling cannot be the reason why we are moral, for if our decisions were based exclusively on this feeling, our decisions would lack the pure, unconditional validity that is required by morality.
Second, Kant points out that the intelligible world has a certain primacy over the world of appearances. After all, our apparent, physical self is only an appearance; our "thing in itself" might be free. Lastly, Kant suggests in his "Concluding Note" that reason has a certain interest in thinking that we are free. When we analyze events in terms of causality, we end up with an infinite regress (a was caused by b, which was caused by c, and so forth). The notion of free will and the unconditional moral requirements that it entails provide a resting place for reason, a "first cause" that explains other events without requiring explanation. These two facts--the primacy of the intelligible world and reason's interest in free will--offer support for our tendency to think of ourselves as free and morally accountable, but they do not settle the question.
Thus Kant leaves us with a notion of freedom that can be neither proved nor disproved, and a notion of morality that is based on that notion of freedom. He cannot explain why or even how we can be moral, yet his account of morality and freedom amounts to a requirement that we suppress our personal needs and desires in the name of "universal law."
If you find these conclusions unsatisfying, you are not alone. Some philosophers have found Kant's notion of freedom unconvincing, and have opted to stick with our intuitive sense (described at the beginning of this Commentary section) that we are most free when we follow our own most urgent needs and desires. ##Nietzsche##, for instance, is famous for arguing that it is unhealthy to reason too much. He suggests that when we base our decisions on an elaborate rational test like the categorical imperative, we only end up with more inhibited choices--we fail to do what we would have freely done had we maintained a more spontaneous decision-making process. Depending on how you define the "self," reason could be just as much of an external force as any physical desire. If "universal law" doesn't fit with what we most want to do, is it really correct to say that we are most "free" when we suppress our desires and follow the law? Why couldn't we "freely" chose to follow our drives and desires instead of reason?
In defense of Kant, his account of morality does fit fairly well with common moral intuitions. By definition, morality involves constraining our selfish inclinations in ways that serve the greater good of humanity. Kant's rationalist morality is no more constraining than any other moral system. Moreover, as Kant points out, the categorical imperative can only be used to test the moral quality of our motives; it cannot prescribe the specific motives we should adopt. Kant seems to have confidence that reason will impose the same demands on all people. Nevertheless, he leaves it up to us to make use of reason to determine what moral maxims could serve as universal laws.