The only thing that is good without qualification is goodwill, which means acting for the sake of duty to follow the moral law, which is universal
Kant's deontological ethics
Ethical theory focused on duty and the moral law
Good will
The source of moral worth and the only pure good in the world. It is not selfish or geared towards any ulterior motives. A good will is one which acts for the sake of duty.
Duty
Acting for the sake of duty, which is the source of moral worth according to Kant
Moral law
Universal laws that we have a duty to follow, according to Kant
Categorical imperative
Kant's test for whether a maxim/rule is a universal moral law
Contradiction in conception
One of Kant's tests for the categorical imperative - a maxim must not result in a self-contradictory conception of the world
Contradiction in will
One of Kant's tests for the categorical imperative - we must be able to rationally will a maxim to become a universal law
Humanity formula
Another formulation of Kant's categorical imperative - to never treat people merely as means, but always as ends in themselves
Not all universal maxims are moral (and vice versa)
Kant's ethics ignores consequences
Kant's ethics ignores other valuable motivations beyond duty
Kant's ethics can lead to conflicts between duties
Hypothetical imperatives
Moral laws qualified by an 'if' statement, according to Philippa Foot
Categorical imperatives
Moral laws not qualified by an 'if' statement, that apply universally, according to Kant
Foot argues there is no rational reason to follow categorical imperatives if you don't accept them
