Groundwork of the Metaphysics of Morals | Study Guide

Immanuel Kant

Download a PDF to print or study offline.

Study Guide
Cite This Study Guide

How to Cite This Study Guide

quotation mark graphic


Course Hero. "Groundwork of the Metaphysics of Morals Study Guide." Course Hero. 8 Jan. 2018. Web. 19 Jan. 2019. <>.

In text

(Course Hero)



Course Hero. (2018, January 8). Groundwork of the Metaphysics of Morals Study Guide. In Course Hero. Retrieved January 19, 2019, from

In text

(Course Hero, 2018)



Course Hero. "Groundwork of the Metaphysics of Morals Study Guide." January 8, 2018. Accessed January 19, 2019.


Course Hero, "Groundwork of the Metaphysics of Morals Study Guide," January 8, 2018, accessed January 19, 2019,

Groundwork of the Metaphysics of Morals | Section 2 : Transition from Popular Moral Philosophy to Metaphysics of Morals | Summary



This section takes up the results of the analyses in Section 2. There, Kant derived from an analysis of the common conception of duty the definition that "duty is the necessity of an action from respect for the law." In Section 2 Kant works to clarify what makes an action necessary. From this analysis Kant derives the formulations of the categorical imperative.

These formulations show how moral law is applied to maxims, that is, to personal rules for acting. One of the formulations introduces the concept of autonomy, which is then connected to the ideal moral community, the kingdom of ends, as well as to human dignity.

Kant presents important topics and concepts in this chapter. For the purpose of analysis they have been broken out by subhead.

Hypothetical and Categorical Imperatives

Kant next develops a more technical vocabulary to account for the discoveries made in his analysis of the "common moral cognition." Reason commands one to do one's duty, but there are also rational commands dictated by what it takes to satisfy a goal. Kant calls these commands categorical and hypothetical imperatives, respectively.

Hypothetical imperatives are those that tell a person what they should do in order to achieve some end, while categorical imperatives tell a person what they ought to do. The former concern doing something in order to secure a particular end, while the latter concern doing something for its own sake. While hypothetical imperatives do not apply to everyone equally, the categorical imperative does.

It is rational to say to oneself, "If I want to be healthy, I should eat fruits and vegetables." It is also rational to say to oneself, "I must never lie." The difference between the two is the difference between willing the means to achieve an end and willing an end. In both cases, however, it is necessary to do something. A hypothetical imperative asserts that one should will the necessary means to an end. A categorical imperative asserts that one must will the end. One can say, for example, that if eating fruits and vegetables is necessary to the goal of health, then one should eat fruits and vegetables to achieve that goal. One can also say that it is necessary not to lie, and for no reason beyond the moral wrongness of lying.

A hypothetical imperative focuses the agent's attention on the circumstances at hand and the consequences of an action. It also expresses the agent's inclinations, and, while it may inspire approval, it does not inspire respect.

In contrast to a hypothetical imperative, the essential features of a categorical imperative are:

  • that it is necessary to act in a specific way;
  • that it does not include one's own purposes or any ends to achieve;
  • that it does not include inclination;
  • that it contains nothing empirical, i.e., that it abstracts from all specificity; and
  • that it inspires respect.

This specific way of acting is "lawlike," which is to say, in thinking about the maxim of the action, one must consider whether it could be a law. Kant clarifies the notion of law by adding that the maxim of the action could be "a universal law of nature." Nature is a coherent system of laws, and morality parallels nature to the extent that one's maxim for acting could be part of a system of moral laws, such as "One ought never lie," or "One ought to develop one's talents."

It is possible to know the categorical imperative because it is a statement of a particular type: it is "synthetic a priori." It is a priori, because it is known independently of experience—and because it is not true by definition, it is synthetic. An analytic statement is true by definition, such as "All triangles are three-sided figures." One need only understand the meaning of "triangle" to extract from it "three-sided figure." On the other hand, knowing that "ought" means "what one must do" does not tell one what, exactly, it is one ought to do. Hence, a maxim is supplied. In Section 3 Kant will attempt an explanation of synthetic a priori knowledge of the categorical imperative.

Formulations of the Categorical Imperative

There is only one categorical imperative, but there are variations of expression.

  1. The Formula of Universal Law: "Act only according to that maxim through which you can at the same time will that it become a universal law." Or in other words, "Act as if the maxim of your action were to become by your will a universal law of nature."
  2. Formula of Humanity: "Act that you use humanity, in your own person as well as in the person of any other, always at the same time as an end, never merely as a means."
  3. Formula of Autonomy: Act so that your will regards itself, at the same time, "as a universally legislating will."
  4. Formula of the Kingdom of Ends: "So act as if your maxim were to serve at the same time as a universal law (of all rational beings)."

The categorical imperative is a rationally generated obligation for all rational beings. It is rationally generated because no empirically generated law could hold with the strict universality Kant thinks morality reflects. Moreover, moral deliberation and choice suggest a rational evaluation that something is good. Kant thinks this understanding of morality reflects the inherent dignity and autonomy of every rational agent. As lawgivers, human beings are autonomous. Kant calls externally imposed law "heteronomous." As lawgivers, human beings command themselves to act from respect for themselves as moral agents. In the ideal "kingdom of ends," rational agents legislate and bind themselves by law.

Perfect and Imperfect Duties: Employing the Principle of Universality in the Categorical Imperative

Kant offers four examples to illustrate the nature of the categorical imperative. In particular, he distinguishes between perfect and imperfect duties.

  1. A suicidal person has a narrow, or perfect, duty to himself. That duty is not to commit suicide out of a desire to end his own suffering.
  2. A person in need of money has a narrow, or perfect, duty to others. That duty is not to lie.
  3. A person has a wide, or imperfect, duty to himself: it is to cultivate his talents.
  4. A person has a wide, or imperfect, duty to others: it is to be beneficent.

Every act undertaken is an act that the agent determines is compulsory for self and others. Acts are commanded "perfectly" or "imperfectly" as duties to self or to others. Perfect duties to self or others are duties that must always be done, while imperfect duties are ones that must be done whenever one can. Consequently, it is never permissible to lie or to kill oneself. The lying promise, as discussed in Section 1, cannot be universalized because it is self-defeating. Suicide cannot be universalized because it contradicts the natural impulse to live. Lying violates the conception of law. Suicide violates a proposed law of nature.

Imperfect, or wide duties, are those duties one ought to satisfy whenever possible. It is not possible to relentlessly pursue one's talents, for example, so one cannot be obliged to do so. This does not mean that one should fritter away one's talents in favor of mere amusement. The attempt to universalize a maxim that allows one to avoid cultivating one's talents runs aground. That is because it could not be a law of nature. People have natural capacities meant to be used for their own, and others' benefit. Just as suicide conflicts with the natural tendency to preserve life, so also ignoring one's talents conflicts with their natural purpose.

It is also not possible to help every person in need at every moment, for example, so one cannot be obligated to attempt to do so. This does not mean that one is never obliged to help. Indeed, the attempt of the wealthy person to universalize the maxim not to help anyone, but instead pursue only his own happiness, fails. Just as one cannot universalize the maxim that allows lying promises, because they are self-defeating, so also one cannot universalize the maxim not to offer aid to those in need. A world in which no one offered aid would be a world in which the wealthy and selfish were members—and a world in which they would, at one point, require help they would not receive. Kant does not think people are completely self-sufficient, such that they would never require any sort of assistance.

Perfect and Imperfect Duties: The Formula of Humanity

Humanity is an end in itself. As such, it has absolute value, to which all other values are relative, and for which no other values can be substituted. The man who wishes to commit suicide, then, treats himself as a means to his own end, which is relief from suffering. The man who wishes to lie treats the lender as a means to his end, which is to obtain money.

The same principle of humanity applies also to the imperfect, or "wide," duties. The man who wishes to substitute his talents for his own happiness selfishly uses himself as a mere means. Similarly, the man who wishes not to help others thwarts, rather than supports, their ends.

Humanity is to be respected as the source of value. Treating persons as ends in themselves translates to respecting them as rational beings. Moreover, Kant thinks, treating persons as ends in themselves enlists rational principles that they themselves, as rational beings, would accept. This, in turn, suggests that these principles are ones to which a rational being could consent. So, for example, a rational person would not consent to be lied to precisely because, while the lie occurs, that person could not know the lie is occurring.

The Formula of Autonomy and the Kingdom of Ends

As rational beings, humans are the source of morality. More specifically, it is through one's will that the moral law is "given." Kant argues that the "ground" of the moral law is such that each person is both subject to it and legislator of it. One is subject to the moral law because it has the relevant binding force. One is the legislator of morality because that binding force is internal rather than external. When one acts morally, for example, one acts as an end in oneself. If one acts morally in relation to another person, then one treats that person as an end in himself or herself. To be an end in oneself is to necessitate, or legislate, through willing, that one always be treated as an end. One is, consequently, bound through an act of one's own will.

Kant contrasts the concept of autonomy with heteronomy. To be autonomous is both to be able to know what morality requires and to be responsible for acting as it requires. The autonomous person lives out, as it were, moral principles that are both self-legislating and universally legislated. To be heteronomous is to be directed by anything other than reason.


By itself, a command or an imperative simply directs. "Shut the window!" one may exclaim. The response is an action: the one commanded either does or does not shut the window. However, when the imperative is expressed as a declarative statement, it has a truth value. In other words it is either true or false to declare, "You should shut the window" or "You ought not to tell a lie." Because Kant is interested in showing what makes an action necessary, he is also interested in showing what makes the categorical imperative true.

Hypothetical Imperatives

Hypothetical imperatives reflect instrumental reasoning, in which the actions are instruments, or means to some end. Examples would include statements like: Someone who wants to arrive on campus at a specific time should use the bus as the vehicle to achieve that goal. Someone who wants to perform well on an exam should consult a tutor to aid in learning the material, which in turn supports the goal of performing well. Someone who wants to learn to play the violin should practice the correct finger placements. The first two of these "shoulds" reflect prudential imperatives, while the last reflects an "imperative of skill." The reader should notice that if one does not want to arrive on campus on time, if one does not want to perform well on an exam, or if one does not want to learn to play the violin, these imperatives will simply not reflect true statements. This is why they are described as "hypothetical imperatives." Not everyone agrees that the outcome is necessary or desirable.

The formula of a universal law reflects several important features. One is that it is reciprocal. What is moral for one is moral for all—there are no exceptions, no extra special people that are not subject to it. Another related feature is that it requires a dispassionate or disinterested judgment of the circumstances. Because it exists outside all empirical factors, including one's inclinations, one must judge the circumstances according to a standard that is blind to one's particular interests or the influences of outside factors. Reason alone determines whether the law is moral.

The Categorical Imperative

Kant's application of the humanity formula of the categorical imperative to narrow (or perfect) and wide (or imperfect) duties is complicated, but it mirrors the application of the universal formula to the same cases. Reading them this way should provide a route into the complexity. The reader should recall that the categorical imperative's first two formulations hone in on law—and law of nature—and the inalienable dignity of humanity. One's law is moral as long as it can be universalized either in conception or in willing. In other words, one's law cannot be conceptually contradictory, as is a lying promise. Nor can one's law be self-defeating in practice, as is suicide.

The humanity formula, which articulates the dignity of persons, emerges from the universal formula: When one acts only on those maxims that anyone could also adopt, one respects humanity, that is, one thereby acknowledges the dignity of personhood. This is what Kant means in Section 1 when he asserts that the good will is the one that wills the good and that morality is doing one's duty for its own sake.

Human dignity, unlike that of other things, is inherently valuable. As such, it cannot be quantified, as can those things that are valued at a price. In the marketplace prices are determined by what people are willing to pay for them; goods have transactional and, more importantly, relative value. Dignity, on the other hand, cannot be traded because nothing has a comparable worth. Nothing can be compared to that which is defined only by itself and not in comparison to anything else. Moreover, dignity originates in one's rational nature. Consequently, an attempt to trade one's dignity for some perceived good or other is an attempt to diminish one's value. People, in short, are not to be manipulated for any reason.

The main difference between the first and the third formulations of the categorical imperative is the focus. When one acts "only according to that maxim through which [one] can at the same time will that it become a universal law," one's focus is on following the moral law. When one acts as a moral legislator, one's focus is on creating the moral law.

Autonomy versus Heteronomy

Kant enlists the term autonomy in a way not previously employed. It was common in the world of politics, beginning with the ancient Greeks that a polis, or city-state, was free to generate its own legal documents, such as a constitution and laws, rather than follow those of another city-state. Kant broadens the concept by employing it in his moral theory. One is autonomous when one is free from internal determining influences on the will, such as inclination. One is also free to be a moral law giver.

Kant's distinction between autonomous and heteronomous law should illuminate his focus on the inherent value of the lawmaker and the respect one feels for oneself as a rational lawgiver. The reader can consider, for example, that the categorical imperative is a command of rationality and, as such, is the same for all. Moreover, as such, it is self-given. The Golden Rule, on the other hand, is a religious command. As such, it is other-given. The interest one would have in obeying such a law would be a feeling—fear, perhaps, or desire. Kant thinks the autonomous nature of morality makes it compelling in ways that heteronomous morality cannot be. To act rationally, for example, is to act from an autonomous will, and to act from an autonomous will is to act freely. To be compelled to act by an external force, on the other hand, is to be caused to act by something other than oneself.

This brings the discussion to Kant's conception of a "kingdom of ends." Each person is an end in himself or herself. Collectively, persons constitute a moral community—kingdom of ends. Each individual's actions contribute to, or detract from, that community. As rational beings, people make choices that alter their own lives and the lives of others. Respect for this feature of humanity, Kant thinks, is fundamental to morality.

Cite This Study Guide

information icon Have study documents to share about Groundwork of the Metaphysics of Morals? Upload them to earn free Course Hero access!