Immanuel Kant, Groundwork of the Metaphysics of Morals I

Posted: Mon, Oct 6, 2025

Confronted with a brakeless, self-driving car with 4 passengers in it, Bentham regretted his work on utilitarianism.

[image or embed]

— Ethics in Bricks (@ethicsinbricks.bsky.social) January 16, 2025 at 6:40 PM

How is morality possible? Where does it come from?

God: The divine command theory.

• The Euthyphro problem: God becomes either a detector or a dictator of morality, neither of which is workable.

Human nature: Utilitarianism (pleasure/pain), with or without further deontological constraints.

• The trolley problem: No view gets all the cases right.

Warm-up activity: If neither human nature nor God can provide a solid foundation for morality, what other options could there be?

Kant’s methodology

Here, then, we see philosophy put in fact in a precarious position, which is to be firm even though there is nothing in heaven or on earth from which it depends or on which it is based. Here philosophy is to manifest its purity as sustainer of its own laws, not as herald of laws that an implanted sense or who knows what tutelary nature whispers to it, all of which—though they may always be better than nothing at all—can still never yield basic principles that reason dictates and that must have their source entirely and completely a priori and, at the same time, must have their commanding authority from this: that they expect nothing from the inclination of human beings but everything from the supremacy of the law and the respect owed it or, failing this, condemn the human being to contempt for himself and inner abhorrence. (Groundwork 4:425–26)

Kant on the armchair

Kant’s intervention: Morality is—indeed, must be—grounded in “pure“ practical reason.

• Pure reason: A priori, whose justification does not directly appeal to experience.
• Practical reason: A counterpart to theoretical reason.

His point: The foundation of morality—“the metaphysics of morals”—cannot be given a posteriori, such as by starting from empirical facts about human nature; instead, it has to be given a priori, by appeal to our rational nature.

• Moral laws apply to all rational agents, not merely—and even more incredibly, not all—human beings.
  • Kant’s conception of reason is not beholden to the particularities of how human beings reason.
  • A perpetual difficulty for Kantians: Ableism, as well as the moral status of non-human animals.
  • A often-dismissed embarrassment: Kant’s racism.
  • Also: Misogyny (more on this later).
• Requirements of morality are requirements of rational agency.
  • In a striking way, immoral acts are immoral because they are irrational.
  • What notion of reason could make sense of this?

Why? G 4:389, 408.

• The empirical work is anthropology, not philosophy.
  • Better: Morality is not about “what happens but rather laws for what ought to happen even if it never does” (4:427).
• Moral laws hold with “absolute necessity” and thus universality. The only way for this to work is if moral requirements depend on neither what human beings are like nor what the world is like, both of which are only contingent.

Kant against the case method

How does one do this? G 4:408ff.

• Not from experience.
• “Nor could one give worse advice to morality than by wanting to deriveit from examples.” Moral laws are general, in accordance with which examples are determined.
• Not by analyzing popular moral concepts. “[T]here is no art in being commonly understandable if one thereby renounces any well-grounded insight.”

Kant: “[B]ecause moral laws are to hold for every rational being as such, [we must] derive them from the universal concept of a rational being as such, and in this way to set forth completely the whole of morals, which needs anthropology for its application to human beings” (4:412).

• Rational agents act not in (mere) conformity with reason but from reason.
• For Kant, even actions that promote happiness have no “moral worth” if they do not express what he calls a “good will” (~properly governed by practical reason) (4:394).
  • ~instrumental vs. intrinsic value.

Kant on reason as self-legislating

Moral laws are not “out there” to be discovered by reason, but originate from our own rational agency and are in this way self-imposed.

• Kant’s conception of autonomy: “For, if one thought of him only as subject to a law (whatever it may be), this law had to carry with it some interest by way of attraction or constraint, since it did not as a law arise from his will; in order to conform with the law, his will had instead to be constrained by something else to act in a certain way” (4:432–33).
  • The normativity of moral laws depends on rational agents committing to them as authoritative through practical reason.
• Autonomy is self-legislation but not in a democratic way.
  • “[H]e is subject only to laws given by himself but still universal” (4:432).
  • Acting autonomously (rather than “heteronomously”) and thus freely essentially involves acting from practical reason, and reason necessarily agrees with reason.
    • While we can be mistaken about what reason requires of us, we cannot autonomously do something morally wrong while recognizing that it is incompatible with reason.
    • In other words, we cannot act on our own to do wrong; we must in some way be acted upon by irrational impulses.
  • Is the masculine pronoun incidental or significant?
    • Womanhood ~ the bodily & affective ~ the unreasonable.
    • “[A]bove all there lies in the character of the mind of this sex features peculiar to it which clearly distinguish it from ours and which are chiefly responsible for her being characterized by the mark of the beautiful. On the other hand, we could lay claim to the designation of the noble sex” (Observations on the Feeling of the Beautiful and the Sublime 2:228).
    • “Women will avoid evil not because it is unjust but because it is ugly, and for them virtuous actions mean those that are ethically beautiful. Nothing of ought, nothing of must, nothing of obligation. To a woman anything by way of orders and sullen compulsion is insufferable. . . . It is difficult for me to believe that the fair sex is capable of principles, and I hope not to give offense by this, for these are also extremely rare among the male sex” (2:231–32).

Example: Is it a moral law that one can “make a promise with the intention not to keep it?”? (G 4:402–3)

• A utilitarian may reject this as a moral law due to “results feared.”
• By contrast, Kant rejects it on the grounds that it is self-defeating, “for in accordance with such a law there would properly be no promises at all, since it would be futile to avow my will with regard to my future actions to others who would not believe this avowal or, if they rashly did so, would pay me back in like coin; and thus my maxim, as soon as it were made a universal law, would have to destroy itself.”
  • “Maxim”: My own subjective principle.
  • Kant’s theory is a thoroughly deontological one.

“Two things fill the mind with ever new and increasing admiration and reverence, the more often and more steadily one reflects on them: the starry heavens above me and the moral law within me. I do not need to search for them and merely conjecture them as though they were veiled in obscurity or in the transcendent region beyond my horizon; I see them before me and connect them immediately with the consciousness of my existence” (Critique of Practical Reason 5:161–62).

Kant's moral philosophy

[image or embed]

— Robert Talisse (@roberttalisse.bsky.social) November 12, 2024 at 1:09 AM