KANT: Fundamental Principles of the Metaphysic of Morals [Sections II-III]

Fundamental Principles of the Metaphysics of Morals by Immanuel Kant

SECTION II: Transition from Popular Moral Philosophy to the Metaphysic of Morals

  • One will not find a pure moral action – i.e. an action motivated solely by a respect for duty – in experience. It is always at least doubtful whether an action is done strictly from duty, and not motivated by some other selfish goal.Thus, some philosophers mistakenly conclude that there is no such disposition and that all human behavior is motivated by self-love.
  • Even when we consider our own actions, it is impossible to determine whether we are acting morally from pure motivations of duty.
  • Moral laws must be derived a priori; for experience cannot produce universal laws that are applicable to all because of their circumstantial nature.
  • The idea of moral perfection – God – is an a priori concept.
  • Previous philosophers mistakenly search for moral principles by considering the nature of man, rather than deriving the principles a priori.
  • To act honestly form some motivation of reward in this life or an afterlife eliminates the moral worth of the act.
  • By the continued application of moral laws derived from Reason, the influence of Reason on action can, by degrees, overpower the influence of the passions and inclinations.
  • Everything in nature works according to laws. Rational beings alone have a will that acts upon conceptions of laws.
  • Hypothetical imperatives command actions that are necessary expedients to something else that is desired. Categorical imperatives command actions that are necessary in themselves without reference to another end.
  • In imperatives of skill, whoever wills the end wills the indispensable means to the end. However, our notions of happiness are so indefinite and inconsistent that one can never definitely and consistently will a particular end so that prudence can show him the means to attain that end. This is because the elements of happiness are empirical, and thus require omniscience to properly discern the means to attain the maximum welfare in the present and future.
  • Thus, these imperatives of skill are not commands, but rather counsels; for the means to promote the happiness of a being are completely insoluble.
  • The categorical imperative is a law that must be followed. The imperatives of skill or prudence are only conditions necessary to satisfy some arbitrary purpose. If we choose to give over this purpose, then we are not obligated to perform the means to attain it.
  • Categorical imperative: “Act only on that maxim whereby thou canst at the same time will that it should become a universal law.” All imperatives of duty can be deduced from this law.
  • To commit suicide is not in accordance with the categorical imperative because a system of nature that commands beings to commit suicide would not exist.
  • A man finds it necessary to borrow money to buy food. He knows that he will not be able to repay the money. Should he make a false promise? Kant says that if one were to universalize the maxim that one should be able to make false promises in dire circumstances, then the concept of a promise would not exist and one would not be able to make a false promise. Thus, making a false promise transgresses the categorical imperative.
  • A man cannot neglect the cultivation of his talents because rational beings necessarily will that their faculties be developed, since they serve him for all sorts of purposes.
  • One cannot neglect assisting others in need if it is within one’s power to provide assistance; for a will that resolved that no one should help others would contradict itself when it needs assistance. [But what if the will does not desire assistance, though it needs it to survive?]
  • Maxims fail the categorical imperative test in two ways: the universalization of the maxim creates an inconceivable and absurd reality; the universalization of the maxim contradicts our own will.
  • The will determines one’s self to action in accordance with laws. If the law is established upon pure reason, then it holds for all rational beings. If the law is established upon inclinations, then it is subjective and holds for only the individual will that chose that particular law.
  • All rational beings are ends in themselves. Man has an absolute worth independent of other considerations because he has a rational will. Man is not merely a means to be used arbitrarily by this will or that. All objects of inclinations only have conditional worth; if the inclination did not exist, then the object would not have any worth.
  • “So act as to treat humanity, whether in thine own person or in that of any other, in every case as an end withal, never as a means only.”
  •  It is wrong to commit suicide because one would will that a human would be treated as a means to an end – that one would destroy one’s self to maintain a tolerable condition or avoid painful circumstances.
  • It is wrong to give false promises and attack another’s freedom or property because one would be using others as means to an end rather than treating those human beings as ends in themselves.
  • The ends of every man, which are ends in themselves, are the ends of every other man; and thus men have an obligation to forward the ends of other men. The natural end of every man is happiness. One therefore ought to promote the happiness of others.
  • The will is both the author and the subject of the universal law.
  • Previous moral philosophies failed because they provided maxims that were not determined by the will itself, but rather the maxims had self-interests as their goal. Thus, the moral philosophies could only give hypothetical imperatives.
  • The kingdom of ends is a union of all rational beings in a system by common laws – i.e. those laws which command all rational beings to treat itself and others as ends, and never as mere means to another end.
  • Autonomy, or the ability to legislate universal laws, is the basis for human dignity.
  • Every rational being is worthy of being a member of the kingdom of ends; for otherwise, he would be subject to the physical law of his wants.
  • Autonomy of the will is the supreme principle of morality.
  • Heteronomy of the will is a will that does not give itself a law, but rather is given a law by an external end – i.e. I ought to do this because I desire that. On the contrary, an autonomous will states “I ought to do this even though I do not desire to do so.”
  • Empirical principles are incapable of serving as a foundation for moral laws. There is no universality in the laws that it legislates because of the unique circumstances encountered by different rational beings. It is quite a different thing to make a prosperous man and a good man.
  • The theological view of God is mistaken. It is founded upon attributes derived from desire for glory, authority, might, and vengeance.


“The notion of happiness is so indefinite that although every man wishes to attain it, yet he never can say definitely and consistently what it is that he really wishes and wills. The reason of this is that all the elements which belong to the notion of happiness are altogether empirical, i.e., they must be borrowed from experience, and nevertheless the idea of happiness requires an absolute whole, a maximum of welfare in my present and all future circumstances. Now it is impossible that the most clear-sighted and at the same time most powerful being (supposed finite) should frame to himself a definite conception of what he really wills in this. Does he will riches, how much anxiety, envy, and snares might he not thereby draw upon his shoulders? Does he will knowledge and discernment, perhaps it might prove to be only an eye so much the sharper to show him so much the more fearfully the evils that are now concealed from him, and that cannot be avoided, or to impose more wants on his desires, which already give him concern enough. Would he have long life? who guarantees to him that it would not be a long misery? would he at least have health? how often has uneasiness of the body restrained from excesses into which perfect health would have allowed one to fall? and so on. In short, he is unable, on any principle, to determine with certainty what would make him truly happy; because to do so he would need to be omniscient.”


“We cannot too much or too often repeat our warning against this lax and even mean habit of thought which seeks for its principle amongst empirical motives and laws; for human reason in its weariness is glad to rest on this pillow, and in a dream of sweet illusions (in which, instead of Juno, it embraces a cloud) it substitutes for morality a bastard patched up from limbs of various derivation, which looks like anything one chooses to see in it, only not like virtue to one who has once beheld her in her true form.”




Kant writes that the idea of moral perfection – God – is an a priori concept. We do not experience God in the world, we merely have a conception of Him as we have conceptions of cause and effect, immortality, and free will. This was a controversial statement in the late 18th century. Kant is essentially arguing that God might only be an idea in our minds, just as causation might only be an idea within our minds. Both notions are inherent in our reasoning capacity, and are used to understand the world that we perceive. However, these ideas are only used to understand the world, they do not necessarily accord with reality.


I believe that this following scenario shows the inconsistence in Kant’s moral philosophy. A man finds it necessary to borrow money to buy food. He knows that he will not be able to repay the money. Should he make a false promise? Kant says that if one were to universalize the maxim that one should be able to make false promises in dire circumstances, then the concept of a promise would not exist and one would not be able to make a false promise. Thus, making a false promise transgresses the categorical imperative. However, in this type of situation, there are two moral imperatives that the man must perform, but the two actions are in direct conflict with one another – i.e. the categorical imperative commands men to preserve their life and to not make false promises. It is impossible to do both, and thus one is compelled to transgress the categorical imperative. Perhaps a joker might qualify the imperative to preserve one’s self by arguing that the law commands a person to preserve their life within the bounds of the other laws ordained by the categorical imperative – i.e. one should seek all other means to preserve their life that do not transgress the maxims derived from the categorical imperative. Perhaps the man in the preceding example could have found food another way besides making a false promise, a way that is not morally wrong. But if we concede the fact that it is impossible to obtain sustenance in any other way, I believe that it is reasonable to conclude that the man is in a situation in which he must determine whether to commit suicide or make a false promise, both actions being contrary to Kant’s categorical imperative.

SECTION III: Transition from the Metaphysic of Morals to the Critique of Pure Practical Reason

  •          The concept of freedom is the key that explains the autonomy of the will
  •          Freedom must be presupposed as a property of the will of all rational beings
  •          It is impossible to know how the world truly is – i.e. form the viewpoint of a god-like being. The world may be entirely different than the way it appears to us. This is because our minds have certain structures that process the phenomena of the external world and present those phenomena to our minds in a manner that is intelligible to us.it is only in the noumenal world – the world as it really is, the world of understanding – that we can understand ourselves to possess and exercise free will. In the natural world, everything is determined by physical laws.
  •          Reason is the faculty by which a man distinguishes himself from everything else.
  •          Man belongs to world of sense when he is determined by fears and inclinations. Man belongs to the intelligible world when he is determined by the dictates of reason.
  •          As a member of the intelligible world, man can never conceive of the cause of his own will without a notion of freedom of the will.
  •          The noumenal world is more fundamental than the world of appearances. Thus, the moral laws of the noumenal world apply to the world of appearances too.
  •          How is a categorical imperative possible?

o   If we are only members of the physical world, then all our actions are determined by desires and fears. But we are members of both the physical and intelligible worlds. When we act in accordance with the laws dictated by Reason, then we are acting autonomously – i.e. we are most free when we obey the laws of Reason. When we act in accordance with laws determined by our fears and inclinations, then we are essentially a slave to those passions, and are not free.

o   The categorical imperative is possible because the idea of freedom makes us members of the intelligible world; and therefore we are universal legislators and subjects to the laws of Reason.

o   Even consummate villains wish to emulate those who are exemplary moral beings, despite great sacrifices of comfort and advantages. Only the villains’ fears and inclinations hinder them from becoming such men.

  •          Of the extreme limits of all practical philosophy

o   It is not a contradiction that we are free in the noumenal world and causally determined by physical laws in the world of appearances because the claim to freedom applies to one world, and the claim to determinism applies to the other.

o   We cannot explain how freedom is possible or how pure reason should have anything to say about morals because we cannot directly experience the noumenal world.


After reading this treatise, I am still unconvinced by Kant’s moral philosophy. To me, moral formulas are useless in true moral dilemmas. Oftentimes people will not have the time to consider whether a particular action is moral or immoral. Though Kant argues that one can cultivate a moral disposition by practicing the exercise of universalizing intended actions, there are some circumstances that are too complicated to be solved by a simple application of the categorical imperative. I have already discussed a few examples, so I will not further investigate possible situations.


Despite all this, I was delighted to read Kant’s philosophy of free will. I think that he provides a very satisfactory answer to this ancient dilemma. Though some people might be dissatisfied that the upshot of the argument is that we are unable to come to a conclusion regarding the subject, I believe that Kant’s explanation of our incapacity to handle this subject to be very convincing. I have always been suspicious about my own perceptions of the external world since studying Descartes. Magic tricks, sticks bending in water, mirages, hallucinations, etc. are all evidence that support the claim that we cannot perceive the world as it truly is. Kant’s innovation about the structures of the mind whereby we process the stimuli of the physical world, and thus are limited to our own unique understanding of the world, which might have very little correlation with the world as it truly is, is remarkable and renders Kant worthy of the reverence paid to him in these days.


I found this very helpful and concise summary of this treatise at the following web address.


“Central elements in Kant’s ethic are:
–denial of consequentialist considerations as relevant to right or wrong
–notion of obligation or duty to the moral law as of sole moral worth
–developing concept of the rational will as a central human characteristics that enables knowledge of the moral law (vs. the heteronomous will)
–the categorical imperative as the command of the rational will that provides the form of that law

Kant parallels moral law to physical law in the sense that both lay claim to:
–universality: it is true everywhere for everyone, i.e.  binding on all agents
–necessity: it is always true i.e. is binding on every occasion
–a priori: it is neither gained from nor falsified by experience (controversial in physics)

But moral law is unlike physical law in that its laws are prescriptive rather than descriptive, i.e. they tell us what should be done. Indeed, Kant claims that even if nobody ever performed a morally worthy act we would still know whether some sort of intended action was of moral worth

Foundation of the Metaphysic of Morals

Kant believes he is making explicit what we already in a sense know: ask yourself about an action “What if everyone did that”?
–yet the deontologist does not focus on consequences
–rather, the point is to try to will the universality and necessity of an act consistently with reason: an immoral act is one that is contradictory or incoherent when universalized

From this sort of consideration, the rational will issues the categorical imperative, a maxim ( or rule ) whose general form is: “I can universally will that in a moral community people perform action x”
–the act is evaluated not by its consequences but by its motive, i.e. by the rational will (not just any motive such as inclination but only by the rational will)
–a good will (i.e. the rational will) is all that matters morally

An a priori knowledge of ethics is assumed when making a moral judgement, which is evident to us in our everyday concept of duty:
–duty commands necessarily and without exception, for all rational beings
–duty is an a priori concept, i.e. cannot be known from experience yet is present always in experience
–(the concept of the “a priori” is an element in Kant’s critical philosophy: given what we know about the world, we discover the underlying structure of the mind and how it conditions all possible experience)
–all we can know from experience is what people do, not what they should do, yet we know that there are things that people should do: thus such knowledge is a priori
–duty involves universality and necessity, which are not empirically given but are essential to the notion of law and unlike physical law it involves values, not facts
–so, the foundation of ethics is uncovered in duty which embodies these features of universality and necessity
–rational ethics seeks the a priori element of morality which duty, not experience, provides
–duty consists in letting reason be the motive and guide in all our actions, not acting according to inclination or natural disposition which are unreliable and partisan

So, an action may be done (1) from inclination and be inconsistent with duty; (2) from inclination and be consistent with duty; or (3) from duty and of course consistent with duty: only the last (#3) is a morally worthy act. One cannot logically do one’s duty from inclination.

Categorical Imperative (CI): There are three formulations that Kant gives for the CI. The first is the

1. Natural Law formulation:
–“Act only on that maxim whereby thou canst at the same time will that it should become a universal law”
–it is construed as a test of the rightness of an act
–note the natural law phrasing, capturing the universality and necessity of law: choose as though your choice has the power to transform the world so that your action is an universal law
–it ties morality to formal characteristics of rationality, universality, and necessity and denies the moral worth of expectations of good outcomes or anything contingent
–basically it prohibits us from letting inclination guide our actions; willing is all and the rational will always appeals to the CI

Kant divides moral imperatives that result from the CI into two sorts, each of which may involve a duty to self or a duty to others:
–perfect duties:
–those binding on all rational beings under all circumstances without exception
–to will the opposite results in a logical contradiction when CI is applied
–imperfect duties:
–those binding on all rational beings but not required on all occasions, i.e they admit exceptions as to when (but not whether) they are fulfilled
–to do otherwise on a given occasion does not result in a logical contradiction, but a contradiction in rational agency: a rational agent could not will that they never be fulfilled
–perfect duty to self: refrain from suicide
–perfect duty to others: repaying debts
–imperfect duty to self: developing one’s talents
–imperfect duty to others: giving to charity

2. Persons as Ends formulation–the second formulation of the CI is:
–“So act as to treat humanity, whether in thine own person or in that of any other, in every case as an end withal, never as a means only”
–when we try to make “exceptions” of ourselves by engaging in immoral practices, i.e. when we follow the will of inclination rather than the rational will, not only do we violate the universality of the CI, but we effectively are willing a world in which others are means to our ends.
–this formulation of the CI (which Kant believes to be equivalent to the first) captures the sense of the unconditional worth of the human being
–the CI is grounded in the human being’s rational will which gives human beings this unconditioned worth; to treat a human being as a means is to recognize in them only a hypothetical worth as an instrumental means, not as a subject possessing inherent worth, i.e. an end.
–it is generally felt that this formulation most directly establishes the absoluteness that is necessary to ground rights, although each formulation does at least indirectly –examples of perfect & imperfect duties to self and others, derived from this formulation, are furnished on pp. 61-2.

3. Kingdom of Ends formulation–the third formulation of the CI is:
–“Therefore every rational being must so act as if he were by his maxims in every case a legislating member in the universal kingdom of ends”
–this means that one must take no action that is inconsistent with it being a law followed by all rational agents: collectively, a kingdom of ends
–a kingdom of ends is composed of rational beings who are able to and simultaneously must will so as to legislate for all rational agents
–since freedom is a necessary condition for any willful action, Kant, by this formulation, seeks to reconcile the freedom, necessary for willing, with the notion of following an imperative or command
–it is only insofar as we are simultaneously givers and receivers of the law that the imperative is not imposed or coercive but freely issued and obeyed by the rational agent
–so, acting heteronomously (conditionally, with regard to consequences, habits, inclinations, restraints etc.) is not autonomous action and not moral action: one must be governed by a law that one freely imposes on oneself (and all rational agents)
–thus freedom and law are unified in this formulation: the moral world is law governed, as in the physical world, but not deterministic insofar as it presumes autonomy which, again, is necessary for truly moral action.

–Kant thinks that each formulation entails the same duties as the other two but it isn’t clear that this is true, and he supports them with different examples
–no guidelines are offered as to when or how often we must perform imperfect duties
–no decision making criterion is offered to determine a rational imperative when perfect duties conflict: they all seem inviolable yet they can and do come into conflict. We need a way to prioritize them to establish which are more important than others and it isn’t clear that Kant’s theory can generate such a criterion.”

Fundamental Principles of the Metaphysics of Morals by Immanuel Kant

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