Meta

Section I: Transition from Common Rational to Philosophic Moral Cognition

Section I serves as the foundation by analyzing ordinary moral thinking ("common cognition") and extracting its philosophical principles. Kant begins with the good will—the only thing unconditionally good, good in itself regardless of consequences. From this analysis, he derives three key propositions:

1. Morality is done out of duty — not from inclination or self-interest

2. Moral worth depends on the maxim (principle) of action, not its results or purpose

3. Acting from duty means acting out of respect for the moral law

Kant concludes Section I by identifying the moral law: act only on maxims that can become universal law. This sets the stage for Section II's deeper investigation

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Section II: Transition from Popular Moral Philosophy to Metaphysics of Morals (4:406-445)

The Critique of Popular Moral Philosophy

Kant opens Section II by arguing that morality cannot be based on empirical observation, feeling, inclination, or external authority (including religious commands). Popular moral philosophy fails because:

• It relies on contingent human nature and psychology

• It cannot provide objective, universal moral truths

• Moral decisions based on fear, desire, or preference are not truly moral

The Imperatives: Hypothetical vs. Categorical

Kant introduces a crucial distinction between two types of rational commands:

Table

Hypothetical imperatives are analytic—we cannot will an end without willing the means. Categorical imperatives are synthetic a priori—they must be established through pure reason alone, independent of any empirical conditions

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The Categorical Imperative: Formulations

Kant argues there is only one categorical imperative, expressed in several formulations:

1. Formula of Universal Law (FUL)
"Act only according to that maxim through which you can at the same time will that it become a universal law."
Or: "Act as if the maxim of your action were to become by your will a universal law of nature."

Kant tests this with four examples (suicide, false promising, neglecting talents, refusing beneficence), showing how maxims that cannot be universalized without contradiction are immoral.

2. Formula of Humanity (FH)
"Act in such a way that you treat humanity, whether in your own person or in the person of any other, never merely as a means, but always at the same time as an end."

Rational nature is an end in itself—intrinsically valuable, not merely instrumentally valuable. This formulation emerges from the first: when we universalize our maxims, we respect the dignity of persons.

3. Formula of Autonomy (FA)
"The idea of the will of every rational being as a universally legislating will."

4. Formula of the Kingdom of Ends (FRE)
"Act according to maxims of a universally legislating member of a merely possible kingdom of ends."

Autonomy vs. Heteronomy

Section II culminates in Kant's revolutionary concept of autonomy (self-legislation):

• Autonomy: The will is a law to itself. We give ourselves the moral law through reason. This is true freedom—acting according to laws we legislate for ourselves

• Heteronomy: The law comes from outside (inclination, authority, God, happiness). This is not truly moral because it involves compulsion rather than free self-determination

Kant argues that all previous moral philosophies failed because they sought morality in heteronomy—whether in feelings (sentimentalism), consequences (utilitarianism), or divine commands (theological ethics). Only autonomy provides the necessary foundation for unconditional moral obligation .

The Kingdom of Ends

Kant imagines an ideal moral community—the kingdom of ends—where:

• All rational beings are both lawgivers and subjects of the law

• Each treats themselves and others as ends in themselves

• This represents the complete realization of morality, entered whenever we act according to the categorical imperative

Human Dignity

Dignity arises from autonomy—our capacity to give universal law. Unlike things that have price (relative, exchangeable value), dignity is above all price—it admits of no equivalent. This inherent worth of rational nature is the basis for respecting all persons

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Summary of Section II's Argument Structure

1. Problem: Popular moral philosophy cannot provide objective moral foundations

2. Solution: Pure metaphysics of morals based on reason alone

3. Tool: The categorical imperative (universal, unconditional moral law)

4. Key Insight: Morality requires autonomy (self-legislation)

5. Ideal: The kingdom of ends, where rational beings coexist as ends in themselves

6. Foundation: Human dignity grounded in our rational nature

Section II thus transforms the insights of Section I into a systematic moral metaphysics, establishing that morality is not about what we want or what makes us happy, but about what rational beings must will as universal law.