kantian ethics

The good will is the only thing that is good in itself.
Other qualities like intelligence, courage, and happiness are only good if they are combined with a good will. For example, intelligence could be used for evil purposes, so it's not inherently good.
The good will acts out of duty, not inclination.

Duty: Actions done because they are morally required.
Inclination: Actions done because they align with our desires or feelings.
Kant argues that only actions done out of duty have moral worth. Actions that happen to align with duty but are done out of personal inclination do not have moral worth.
- For example, a shopkeeper who is honest because it's good for business is not acting morally, whereas a shopkeeper who is honest because it is the right thing to do, even if it harms his business, is acting morally.

The categorical imperative is a moral law that is unconditional and universal.
It tells us what we ought to do, regardless of our desires.
It is contrasted with hypothetical imperatives, which tell us what to do to achieve a particular goal.

4.1. Universalizability

Act only according to that maxim whereby you can at the same time will that it should become a universal law.
Before acting, consider whether the maxim (the principle behind your action) could become a universal law that everyone could follow.
- If it cannot be universalized without contradiction, then the action is morally wrong.
- For example, you cannot universalize lying because if everyone lied, then no one would believe anyone, and communication would be impossible.

4.2. Humanity as an End

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 to an end, but always at the same time as an end.
Treating someone as a means to an end involves using them to achieve your own goals, without respecting their own goals and desires.
Treating someone as an end involves respecting their autonomy and treating them as a rational being with their own goals and desires.

4.3. Kingdom of Ends

Act as if you were, through your maxims, a law-making member of a kingdom of ends.
Imagine a world in which everyone treats each other as ends, not merely as means.
In such a world, everyone would be autonomous and rational, and everyone would respect the moral law.

Universality: Kantian ethics provides a universal moral framework that applies to everyone, regardless of their personal beliefs or desires.
Respect for persons: Kantian ethics emphasizes the importance of treating people with respect and dignity.
Clarity: The categorical imperative provides a clear and consistent guide to moral action.

Too rigid: Kantian ethics can be too rigid and inflexible, failing to account for the complexities of moral decision-making in real-life situations.
Conflicting duties: Kantian ethics does not provide a clear way to resolve conflicts between duties.
Abstractness: The categorical imperative can be difficult to apply in practice, as it is abstract and requires careful interpretation.