Groundwork of the Metaphysics of Morals

1. The Good Will: The Unconditional Foundation of Morality

A good will is not good because of what it effects or accomplishes, because of its fitness to attain some proposed end, but only because of its volition, that is, it is good in itself.

Intrinsic Value. Kant argues that the only thing that is good without qualification is a good will. Unlike talents, intelligence, or even happiness, a good will is not good because of its consequences or its usefulness in achieving other ends. Its value is inherent and unconditional.

Beyond Consequences. The moral worth of an action does not depend on its outcome or its success in achieving a desired result. Instead, it is determined by the quality of the will that motivates the action. Even if an action fails to achieve its intended purpose, it can still be morally good if it stems from a good will.

Reason's Purpose. Kant suggests that if nature has given us reason, it is not primarily for the purpose of achieving happiness, as we are not very good at that. Rather, reason's true purpose is to produce a good will, which is the highest good and the ultimate aim of human existence.

2. Duty: Action from Respect for the Moral Law

Duty is the necessity of an action done out of respect for the law.

Acting from Duty. Kant distinguishes between acting in accordance with duty and acting from duty. An action has moral worth only when it is done from a sense of duty, that is, when the agent is motivated by respect for the moral law itself, not by inclination or self-interest.

The Moral Law. Duty is not based on external authority or social conventions, but on the moral law, which is a principle of reason that is binding on all rational beings. This law is not imposed from without but is rather a law that we give to ourselves as rational agents.

Respect for Law. Acting from duty involves a unique kind of motivation: respect for the moral law. This respect is not a feeling or an emotion, but a rational recognition of the authority of the moral law and a commitment to act in accordance with it.

3. The Categorical Imperative: The Universal Law of Action

Act only according to that maxim whereby you can at the same time will that it should become a universal law.

The Supreme Principle. The categorical imperative is the fundamental principle of morality, which is derived from the concept of duty. It is a single, universal principle that applies to all rational beings, regardless of their individual desires or circumstances.

Universalizability. The categorical imperative requires that we act only on maxims that we can rationally will to become universal laws. This means that our actions must be consistent with the idea that everyone else could act on the same principle.

Testing Maxims. To determine whether a maxim is morally permissible, we must ask ourselves whether we could rationally will that everyone should act on that maxim. If the universalization of the maxim leads to a contradiction or undermines the very possibility of the action, then the maxim is morally impermissible.

4. Humanity as an End: Respect for Rational Nature

So act that you use humanity, whether in your own person or in the person of any other, always at the same time as an end, never merely as a means.

Rational Nature. Kant argues that rational beings, because of their capacity for reason and autonomy, have a unique value that is not reducible to their usefulness or their ability to satisfy desires. This value is what Kant calls "humanity" or "rational nature."

End in Itself. To treat humanity as an end in itself means to recognize the inherent worth and dignity of every rational being. We must never treat others merely as tools or instruments for achieving our own purposes, but always as beings with their own ends and purposes.

Respect for Persons. The principle of humanity as an end in itself requires that we respect the autonomy and rationality of all persons, including ourselves. This means that we must treat others as beings capable of making their own choices and setting their own ends.

5. Autonomy: The Will as Self-Legislator

A free will and a will under moral laws are one and the same.

Self-Legislation. Autonomy is the capacity of the will to give itself its own laws, rather than being determined by external forces or desires. It is the ability to act on principles that are self-imposed and universally valid.

Freedom and Law. Kant argues that freedom and morality are not opposed to each other, but are rather two sides of the same coin. A truly free will is one that is governed by the moral law, which is a law that it gives to itself.

Dignity of Reason. The concept of autonomy is closely connected to the idea of human dignity. It is because we are capable of self-legislation that we have a unique worth and are not merely objects to be used by others.

6. Freedom and Morality: Reciprocal Concepts

Freedom and unconditional practical law reciprocally imply each other.

Interdependence. Kant argues that freedom and morality are not separate concepts, but are rather mutually dependent. We can only understand what freedom is by understanding the moral law, and we can only understand the moral law by understanding freedom.

Freedom as a Condition. Freedom is not merely the absence of external constraints, but the capacity to act on principles that are self-imposed and universally valid. This capacity is what makes morality possible.

Morality as a Condition. The moral law is not merely a set of rules or commandments, but a principle that is grounded in the very nature of freedom. It is through the moral law that we become aware of our own freedom and our capacity for self-determination.

7. The Intelligible World: Reason's Perspective

The idea of a pure world of understanding as a whole of all intelligences, to which we ourselves belong as rational beings (though on the other side we are also members of the world of sense), remains always a useful and permitted idea for the sake of a rational belief.

Two Standpoints. Kant argues that we must view ourselves from two different standpoints: as members of the sensible world, subject to the laws of nature, and as members of the intelligible world, subject to the laws of reason.

Freedom and the Intelligible World. It is only from the standpoint of the intelligible world that we can understand ourselves as free agents, capable of acting on the basis of reason rather than merely on the basis of desires or inclinations.

Moral Motivation. The idea of the intelligible world provides a basis for understanding how we can be motivated by the moral law. It is because we recognize ourselves as members of this world that we can be moved by the idea of duty and the worth of humanity.

8. The Limits of Reason: Inexplicable Interest

The idea of a pure world of understanding as a whole of all intelligences, to which we ourselves belong as rational beings . . . remains always a useful and permitted idea for the sake of a rational belief, even if all knowledge stops at its boundary.

The Inscrutability of Freedom. Kant acknowledges that the nature of freedom and the connection between freedom and morality are ultimately inexplicable. We cannot fully understand how it is possible for us to be both free and subject to the moral law.

The Fact of Reason. The moral law is not something that can be derived from experience or from any other source of knowledge. It is a “fact of reason,” a fundamental truth that is revealed to us through our own consciousness.

Practical Faith. Although we cannot fully understand the nature of freedom or the moral law, we can have a rational faith in their reality. This faith is not based on empirical evidence, but on the practical necessity of assuming our own freedom and the validity of the moral law in order to act as rational agents.

Last updated: April 4, 2025