Key Ideas
1. Good will is good without qualification
Its worth does not depend upon talent, happiness, advantage or successful results.
2. Moral philosophy requires an a priori foundation
Universal obligation cannot be derived solely from variable facts about behaviour and desire.
3. Duty is good will under conditions of inclination
For imperfect rational agents, moral law often appears as a constraint upon competing desires.
4. Moral worth lies in the principle of action
An action done from duty is determined by respect for law rather than merely coinciding with it.
5. A maxim is a subjective rule of choice
It expresses what an agent proposes to do and the reason incorporated into that proposal.
6. Hypothetical imperatives are conditional
They direct necessary means only for agents who will a particular end.
7. The categorical imperative is unconditional
It binds rational agents without depending upon an optional desire or expected benefit.
8. Universalise the maxim
Act only on a principle that you can at the same time will for everyone.
9. Some maxims contradict their own conception
A universal practice of false promising would undermine the institution the maxim needs.
10. Some maxims cannot be rationally willed
A world without mutual assistance may be conceivable but conflicts with the needs of finite agents who pursue ends.
11. Perfect duties prohibit specific maxims
They impose strict requirements such as rejecting deception and coercion.
12. Imperfect duties require adopted ends
Self-development and assistance to others allow discretion in how they are realised.
13. Humanity must always be treated as an end
Rational agency may never be bypassed or subordinated merely to another person’s project.
14. Persons possess dignity
Their value is not replaceable by an equivalent or reducible to a market price.
15. Autonomy is rational self-legislation
Freedom means acting on universally justifiable law, not following every personal impulse.
16. Heteronomy cannot ground unconditional duty
Principles derived from desired objects, rewards or happiness remain conditional upon wanting them.
17. The kingdom of ends is a moral community
Every rational being is both subject to and author of laws that respect all others equally.
18. Freedom and morality imply one another
A free rational will is autonomous, while moral deliberation requires acting under the idea of freedom.
19. Human beings occupy two standpoints
They appear within natural causality yet understand themselves practically as rational agents.
20. Practical reason has a boundary
It can establish the necessity of moral law without explaining how freedom operates as an observable mechanism.