1. Kant’s theory of imperatives
Practical imperatives are expressed in ‘ought’ judgments
‘Ought” judgments indicate the influence of reason in human wills
“Holy” wills never experience imperatives
By classifying imperatives, we classify the ways in which reason influences human action

2. Kant’s taxonomy of imperatives
Hypothetical Imperatives
Problematical
Assertoric
Categorical Imperatives

3. Problematical Hypothetical Imperatives
E.g., If I want to get to Chicago by 6 o’clock, I ought to catch the 2:30 train.
Rules of skill
Motivated by particular desires or intentions

4. Assertoric Hypothetical Imperatives
E.g., Since I want to be happy, I ought to develop some hobbies.
Counsels of welfare
Motivated by the universal desire for happiness

5. Categorical Imperatives
E.g., I ought to tell the truth
Commands (laws) of morality
Motivated by Respect for the law

6. The Principle of the Categorical Imperative
Act only on that maxim whereby you can at the same time will that it should become a universal law.
Act as if the maxim of thy action were to become by thy will a universal law of nature.

7. Kant’s Test 1) Formulate the action to be tested as a maxim or rule.
2) Imagine what the world would be like if everyone always acted on this rule.
3) Ask, first, if such a world is possible.
4) If so, ask if it is possible for you simultaneously to act on that maxim and also will that you live in the world in which everyone acts on that maxim.

8. Kant’s examples Two distinctions: Perfect vs. Imperfect duties
Duties to oneself vs. Duties to others
Perfect duty to oneself: One ought not to take ones own life.
Perfect duty to others: One ought not to make lying promises.
Imperfect duty to oneself: One ought to develop ones talents
Imperfect duty to others: One ought to go to the aid of others in need.

9. Why Lying Promises are Wrong
Formulate the Maxim of the action
“When I believe myself to be in need of money I shall borrow money and promise to repay it, even though I know that this will never happen.”
Transform the rule into a universal law:
“How would it be if my maxim became a universal law?”
Immanuel Kant, Grounding of the Metaphysics of Morals, trans. Mary Gregor (New York: Cambridge University Press, 1998), 32.

10. The result of Universalization
The proposed maxim fails the test because it is not universalizable:
“I then see at once that it could never hold as a universal law of nature and be consistent with itself, but must necessarily contradict itself. For, the universality of a law that everyone, when he believes himself to be in need, could promise whatever he pleases with the intention of not keeping it would make the promise and the end one might have in it itself impossible, since no one would believe what was promised him but would laugh at all such expressions as vain pretenses.”
Immanuel Kant, Grounding of the Metaphysics of Morals, trans. Mary Gregor (New York: Cambridge University Press, 1998), 32.

11. Other Formulations of the Categorical Imperative
Principle of Humanity: “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.”
Principle of Autonomy: “The idea of the will of every rational being as a will giving universal law.”
Principle of the Kingdom of Ends: “A rational being must always regard himself as lawgiving in a kingdom of ends possible through freedom of the will, whether as a member or as sovereign.”
Kant believes that all of these formulations are equivalent.
Immanuel Kant, Grounding of the Metaphysics of Morals, trans. Mary Gregor (New York: Cambridge University Press, 1998), 38, 39, 41.