Kantian Ethics

What problem was Kant responding to in the Enlightenment?

Kant was responding to religious conflict in Europe. He thought morality based on different faiths would always lead to disagreement, so society needed a moral system based on something universal.

Why did Kant base morality on reason?

Kant believed reason is universal and allows people to agree on moral rules regardless of religion. A rational moral system would therefore help create a harmonious society.

How did Newton influence Kant’s ethical project?

Kant admired how Newton revolutionised science by grounding knowledge in reason. Kant wanted morality to be revolutionised in the same way: by discovering universal moral laws through reason.

Why does Kant think moral laws must be universal?

Kant argues that reason discovers universal laws, like maths and physics. So morality based on reason must also involve universal laws that apply to everyone.

What does Kant mean by “categorical” moral laws?

Categorical moral laws apply in all cases, regardless of feelings, consequences, or personal desires. They are absolute and unconditional.

What is an imperative?

An imperative is a statement containing moral force, like “should” or “ought”, telling you what to do.

What is a hypothetical imperative?

A hypothetical imperative is conditional:
“You should do X if you want Y.”
It depends on personal goals/desires, so Kant says it cannot be genuine morality.

What is a categorical imperative?

A categorical imperative is unconditional:
“You should do X.”
It applies to everyone, always, and does not depend on personal feelings or consequences.

Why does Kant reject hypothetical imperatives as morality?

Because hypothetical imperatives are based on wants, goals, or outcomes, meaning they vary between people. Kant believes morality must be universal and objective, so only categorical imperatives count.

How many categorical imperatives does Kant think there are?

Kant says there is one categorical imperative, but it has three formulations (three ways of expressing the same moral law).

What is the first formulation of the categorical imperative?

Universal Law Formulation:
Only act on a maxim that you could will to become a universal law.
If everyone cannot do it, it is immoral.

How does stealing fail the universal law test?

If everyone stole, there would be no stable concept of property. If there is no property, stealing becomes impossible. Therefore stealing is not universalizable.

How does lying fail the universal law test?

If everyone lied, trust and honesty would collapse. Without trust, lying would no longer work. Therefore lying cannot be universal law and is immoral.

What is the second formulation of the categorical imperative?

Humanity Formulation:
Always treat persons as an end in themselves, never merely as a means.
This means respecting people as individuals with their own goals.

What does “never merely as a means” mean?

You must never use someone as a tool for your own purpose while ignoring their autonomy or value. People are not objects to manipulate.

What is the third formulation of the categorical imperative?

Kingdom of Ends Formulation:
Act as if you are part of a society where everyone follows Kant’s ethics — a rational moral community.

What is the “good will” in Kant’s ethics?

A good will is the only thing that is morally good without qualification. It means acting with the right motivation: doing your duty because it is your duty.

Why must we act out of duty?

Kant says actions are only morally good when motivated by respect for the moral law, not by sympathy, emotion, self-interest, or desire.

Example: Why should you give to charity according to Kant?

You should give to charity because it is your duty, not because you feel sympathy. If you give only because you “feel like it,” it lacks moral worth.

What are Kant’s three postulates?

Kant argues morality requires us to assume (postulate):

1. Free will

2. Immortality of the soul (afterlife)

3. God

What is a postulate?

A postulate is something we cannot prove through theoretical reason, but must assume in order for ethics to make sense.

Why must we postulate free will?

Without free will, there is no moral responsibility. Free will separates humans from animals and explains why humans can be morally good or bad.

Why must we postulate immortality (afterlife)?

Kant observes that good people often suffer and bad people go unpunished. Ethics requires an afterlife where justice is completed.

What is the summum bonum?

The summum bonum is the “highest good”: a world where virtue and happiness align, with virtue rewarded and vice punished (fulfilled fully in the afterlife).

Why must we postulate God?

God is required to guarantee the summum bonum (ultimate justice), ensuring morality is coherent and meaningful.

What is Sartre’s criticism of Kantian ethics?

Sartre argues duties can clash. Example: a soldier must either:

• go to war to defend their country

• stay home to care for a sick parent
  Both appear to be duties, but the soldier cannot do both.

Why is this a serious problem for Kant?

Because Kantian ethics aims to clearly identify duty. If duties clash, Kant’s theory cannot tell us what the right action is, undermining it as a normative theory.

How does “ought implies can” create a deeper problem?

Kant believes “ought implies can”: you can only have a duty if it’s possible to do it. If two duties conflict and you can’t do both, at least one cannot truly be a duty—yet Kant’s system produced both.

Kant’s response: perfect vs imperfect duties

Kant says:

• Perfect duties never allow exceptions (e.g. always tell the truth)

• Imperfect duties have flexibility in how they’re fulfilled
  So apparent clashes are usually imperfect duties, and you can fulfil both in different ways.

Example of Kant’s response to the soldier dilemma

The soldier could:

• help their country by making bombs at home

• help their parent by paying someone else to care for them
  So the duties don’t truly clash.

Evaluation: why Kant’s defence may fail

Some situations genuinely prevent fulfilling both imperfect duties. If there’s no one to help the parent and no alternative way to help the country, then Kant still can’t decide the correct duty.

What is Stocker’s hospital friend example?

Stocker says imagine a friend visits you in hospital and says:
“I came only because it was my duty.”
This seems cold and morally wrong, showing Kant’s ethics can damage human relationships.

What is Bernard Williams’ criticism (“one thought too many”)?

Williams argues Kantian ethics is unnatural because it makes moral people think about moral law when they should simply act out of love or virtue. Moral reasoning becomes “one thought too many.”

Why does Stocker think acting from duty is a problem?

Stocker argues acting purely from duty prevents acting from genuine virtues like love, friendship, and kindness—yet these are central to ethical life.

Kant’s counter: why are emotions unreliable?

Kant argues emotions are transient and fickle, so they are an unstable foundation for morality. Reason gives stable respect for the moral law.

Barbara Herman’s interpretation of Kant’s view

Herman argues emotions can only lead to the right action by luck, since emotions may push us either way. Only duty reliably produces moral worth.

Evaluation: Aristotle’s response to Kant on emotion

Aristotle argues emotions can be cultivated through rational habit (virtue). If we train ourselves, emotions become reliable and morally valuable. This weakens Kant’s rejection of emotion.

What is Constant’s “murderer at the door” objection?

Benjamin Constant argues that if a murderer asks where their victim is, we should lie to prevent harm. Kant’s absolutism makes truth-telling seem morally wrong in extreme cases.

Modern version of the same criticism

If a Nazi asks whether you are hiding Jews, lying seems morally required. Kant’s view implies lying is always wrong, which conflicts with moral intuition.

Why does this support consequentialism?

Because it suggests consequences matter: morality must consider harm prevention. Pure duty-based ethics seems too rigid and disconnected from reality.

Kant’s defence: why consequences don’t matter

Kant argues we can’t control outcomes. If you lie and the victim is actually there, you become responsible for their death. Therefore consequences cannot be the basis of morality.

Evaluation: why Kant’s defence is flawed

We can control consequences to some degree, so we are responsible to that degree. Singer argues we act based on “reasonable expectations,” so it is rational to lie to prevent likely harm.

What is the biggest strength of Kantian ethics?

It provides a universal, rational, objective basis for morality and avoids moral relativism by grounding ethics in reason and duty.

What is the biggest weakness of Kantian ethics?

It can be too rigid:

• duties can clash

• it undervalues emotion and virtue

• it ignores consequences even when disastrous

One-line AO2 judgement on Kant vs consequentialism

Kant gives moral certainty and universality, but consequentialism may better reflect moral reality because it considers foreseeable harm.