Introduction Act only according to that maxim whereby you can at the same time will that it should become a universal law. (Kant 1993: 30) Kant's categorical imperative is meant to issue from and bind human rational agency and to guide us toward moral duties and away from immoral acts. It has several formulations, but the most famous is stated above. Since the categorical imperative is an imperative, we are morally required to act according to it.
And since it is categorical, we must do so without exception. A hypothetical imperative must
be followed only in certain circumstances. For example, the hypothetical imperative, "if
you're hungry, eat" applies only in certain circumstances, namely, if you are hungry. The
categorical imperative, by contrast, applies in all circumstances. Thus, we are always
morally required to act according to the categorical imperative. What then does the
categorical imperative demand of us? It does not obligate us to perform any particular act
per se; rather, it demands that our acts meet a certain condition: we must be able to will that
the motive (the "maxim") behind an action could be adopted by anyone else in similar
circumstances—that it could become a universal law. The categorical imperative is the
fundamental principle of Immanuel Kant's (1724 - 1804) moral philosophy. A moral
philosophy is a theoretical account of the nature and character of the rights afforded and
obligations constraining rational agents.
Kant devises the categorical imperative as a principle that will satisfy several conditions that he sets for a satisfactory moral theory. We shall review these conditions, Kant's many formulations of the categorical imperative, and its philosophical legacy in the sections below. But before tackling the details, let us consider a few examples of the categorical imperative "at work". This shall help us see how one wills that the maxim behind an action should become a universal law.
Imagine you've made a promise to tutor a friend Friday night, but when Friday comes, you find you'd rather go to a movie. Naturally, you worry what Kant would think; so you ask whether your motivation should become a universal law. In effect, you ask whether there should be a law that promises are never kept. Notice that such a law would not only make the world worse and probably unpleasant to you yourself, it would make promising meaningless. As things are, your promise to your friend gives her reason to believe you will in fact show up to tutor her on Friday; if the promise-breaking maxim were to become a universal law, however, she'd have no such reason. Every attempted promise would just fail, since no one would believe in them. Thus, it is morally impermissible to break a promise.
1 Nature of the concept
Kant deduces the categorical imperative from two maxims: one concerning objectivity and one concerning respect for all persons. The maxim of objectivity says that an act is right only if it would be right for any person in similar circumstances. The requirement to will that one's maxim should become universal law ensures that what is permissible is objectively so. The second maxim focuses on respecting others; it says that an act is right if it treats others "as ends in themselves" and not as "means to an end". These two phrases are very important in Kant’s works and in the works of his followers; they are also, however, difficult to make precise. Roughly, we can say that treating a person as an end in herself is respecting her, while treating a person as a mere means to an end is to exploit her.
1.1 Freedom and autonomy
A puzzle for moral philosophy asks how our decisions can be subject to moral evaluation if the laws of physics determine what our bodies will do at any given time. It seems, for example, that I can be blamed for breaking a promise only if I chose to do so; but if the laws of physics and the state of the universe before I was born determined that I would later break my promise, it seems that I did not choose to do so.
The categorical imperative is also a constraint: it tells us not to act on impermissible maxims. Kant believes that this is constitutive of our "autonomy". Since the categorical imperative is a law of rationality, in acting according to it, we are "authors" of the laws that bind us. Just as a country that governs itself and sets its own laws is autonomous, so is a moral agent who acts according to the categorical imperative, even if those acts were pre-determined by the laws of nature.
1.2 Good will, duty, and the categorical imperative
In addition, notice that the categorical imperative does not directly concern our actions. Rather, it addresses our "maxims", the reasons according to which we act. Each of us has a moral duty to act not simply "in accordance" with what is right but "according to" it. That is, we should act morally for the sake of acting morally, not, for example, because it will make people like us or get us to heaven. If our motivations are not pre-determined by physics, then we may still be free to choose the maxims on which we act, and we may thereby be subject to moral evaluation.
2 The First Formulation
The famous formulation we mentioned above is also Kant's first formulation of the categorical imperative. It is designed to be objective, or universal, and to demand respect for all persons. Kant divides the constraints it delivers into two: perfect and imperfect duties. They correspond to two different ways in which a maxim can fail the demand to be "universalized" in the categorical imperative.
2.1 Perfect duty
Think of a perfect duty as one that can be perfectly satisfied; in the paradigm case, this means we are obligated to refrain from taking on impermissible maxims. Impermissible maxims are identifiable because they result in logical contradictions when we universalize them. Recall that the attempt to universalize breaking a promise results in the meaninglessness of promising. But if promising is meaningless, one cannot make it his will to promise, and so the maxim becomes contradictory. As a result, we have a perfect duty to never break promises, and failing to meet a perfect duty deserves blame.
2.2 Imperfect duty
Imperfect duties, by contrast, cannot be perfectly satisfied, though we do still have a duty to pursue them. Kant gives the example of cultivating one's talents. One can never complete the project of becoming a better singer, and one isn't morally bound to pursue such a project at all times. Thus, one can be perfect by never lying, but one cannot be perfect in cultivating one's singing voice. Thus, the former is a perfect duty and the latter is imperfect. Since they cannot be completed, failing to satisfy an imperfect duty does not typically deserve blame while acting according to one does typically deserve praise.
3 The Second Formulation
When we act, we not only form a maxim on which to act but also an “end” for which we act. Thus, when I brush my teeth, it is in order to maintain healthy dental hygiene. Dental hygiene is the end for which I act. This end is rational for me to adopt given my subjective reasons; others may reject it for their own reasons. So it is with hypothetical imperatives. The categorical imperative, on the other hand, is supposed to furnish objective ends.
An objective end would be rational for all of us to adopt. Given that each of us is autonomous, and so each of us acts according to a law set "from within", it would be irrational and inconsistent with the first formulation of the categorical imperative for one to treat herself as a means to an end. Moreover, since the first formulation demands that we universalize this principle, it follows that we must treat everyone as an end in herself and not merely a means to an end. Thus, we have Kant’s second formulation of the categorical imperative:
Act in such a way that you treat humanity, whether in your own person or in the person of any other, always at the same time as an end and never merely as a means to an end. (Kant 1993: 36)
This formulation makes clear that we have a perfect duty never to treat oneself or others as a mere means to an end.
4 The Third Formulation
The third formulation of the categorical imperative emphasizes the autonomy each of us has as a rational will and provides a vivid heuristic for imagining the universalization of one’s maxims.
Therefore, every rational being must so act as if he were through his maxim always a legislating member in the universal kingdom of ends. (Kant 1993: 43)
Since a rational will is subject only to the laws it sets for itself, one should imagine himself as creating legislation over the realm in which he lives with each act. But we must consider that there are many other "ends in themselves" in the kingdom, and each of these demands and deserves justice and respect under the legislation. Thus, each maxim on which one acts must be such that anyone in the "kingdom of ends" could adopt it and all in the kingdom would still be treated with respect.
5 Normative interpretation
Although Kant developed his moral system from rational principles and constraints on an adequate moral philosophy such as the autonomy of reason, respect for persons, and the objectivity of the moral law, it is illuminating to apply his thoughts to particular situations.
5.1 Deception
Kant claimed that we have a perfect duty to avoid all kinds of maxims to deceive. As with breaking a promise, the general idea is that universalizing a maxim to deceive would render meaningless the sincere actions on which deception depends. For example, lying succeeds in deceiving someone, the target, only if the target is inclined to believe the lie. If a maxim to lie were universalized, however, then no one would be inclined to believe what others say. As a result, lying would be meaningless. Kant concludes that we have a perfect duty not to lie.
5.2 Theft
Kant held that having respect for persons demands that one never take any action against another person if that person could not possibly consent to it. To do otherwise is to violate the second formulation of the categorical imperative. Theft violates this condition, since it is taking something from someone without his or her consent. The nature of theft, then, makes it impossible to steal with the victim's consent. Since theft would thus lead to a contradiction of others' autonomy if universalized, we have a perfect duty to avoid it.
5.3 Suicide
Kant also believed that we have a perfect duty not to commit suicide. In his argument, Kant focuses on suicide out of self-love. He assumes that self-love is the principle that typically leads to "the furtherance of life", but when one adopts a suicidal maxim, this is contradicted. Universalizing the principle that one could commit suicide out of self-love would thus, according to Kant, render self-love meaningless, since it could not lead both to the furtherance and the cessation of life.
5.4 Laziness
We have an imperfect duty to develop our talents, but do we have a perfect duty to not let our talents go to waste? Could each of us "do nothing"? Although Kant grants that society might not collapse if everyone did nothing, he suggests that a person contemplating such a maxim of laziness would have to imagine having no pleasures to enjoy. For only if others worked to supply nourishment, entertainment, etc. could one's own laziness be enjoyable. Thus, Kant claims that one could not will a universal laws of laziness, and thus it is impermissible.
5.5 Charity
We cannot of course perfect whatever duty we have to give to charity; but can we will that it should be a universal law that we do not give to charity? Kant thinks not. Again, although society might not collapse if no one gave to charity, Kant denies that anyone could will that we live in such a society. Kant imagines that anyone contemplating such a maxim would someday want the charity and sympathy of others, but he would be depriving himself of that much by willing that a maxim against charity be universal law.
5.6 Cruelty to animals
Since Kant's duties arise primarily out of respect for rational agents, one may wonder whether Kant finds it permissible to treat animals cruelly, assuming that animals are not rational agents. Kant finds it impermissible on the grounds that it violates a duty to oneself. For each of us has a duty to deepen our capacity for compassion, and treating sentient beings cruelly has the opposite effect. Thus, it is contrary to duty and impermissible.
6 Normative criticism
6.1 The Golden Rule
The Golden Rule says we should each treat others as we wish to be treated; it has a superficial similarity to universalizing in that each principle exhorts us to imagine ourselves "on both sides" of one's acts, as both agent and victim. But the two are not equivalent. Note that the Golden Rule turns on subjective preferences: we are to treat others in ways that we like based on our own subjective preferences. If one prefers to be deceived, then one may lie and follow the Golden Rule; but the categorical imperative could license no such thing no matter how one feels about being deceived.
6.2 Inquiring murderer
Kant's claim that we have a perfect duty to never lie runs afoul of our intuitions in some cases. Imagine that a friend of yours, Immanuel, is hiding in your attic from a homicidal maniac, Jason. When Jason knocks on the door and asks for Immanuel's whereabouts, may you lie? Kant says "no"; it would be morally impermissible since it would treat Jason as a means to an end rather than an end in himself.
Kant's position on this point is so counterintuitive that one might reject the possibility of categorical imperatives or even Kant's entire moral system on this basis. But it's worth noting that Kant can mitigate the extent to which his view is counterintuitive. First, Kant makes the formal point that actions are to be judged not by their consequences but by the maxims that give rise to them, and so if Immanuel is murdered, it doesn’t affect the moral status of a lie. Second, there may be ways for one to withhold Immanuel's whereabouts without deceiving Jason. One might, for example, remain silent in the face of Jason's questions.
6.3 Questioning autonomy
Soren Kierkegaard questioned the extent to which we are autonomous in practice. Whereas Kant says that morality requires us to bind ourselves by the rational and objective law, Kierkegaard doubts that many of us can bind ourselves so completely. On the contrary, Kierkegaard suggests that we often excuse ourselves of the inconvenient moral laws or overlook transgressions whenever they occur. Kant might reply that this only underscores the difficulty of truly acting according to moral duty.
REFERENCES
1. Johnson, Robert, "Kant's Moral Philosophy", The Stanford Encyclopedia of Philosophy (Summer 2010 Edition), Edward N. Zalta (ed.), URL =
2. Kant, Immanuel. Grounding for the Metaphysics of Morals, 3rd ed., translated by James W. Ellington. Hackett, [1785] 1993.
3. Rohlf, Michael, "Immanuel Kant", The Stanford Encyclopedia of Philosophy (Summer 2010 Edition), Edward N. Zalta (ed.), URL =
