Aquinas: natural law

Thomas Aquinas held that reason can discern God’s purposes in nature. The synderesis rule is to "do good and avoid evil." He distinguished four types of law (eternal, divine, natural, human).

The five primary precepts are: Preservation of life, Ordering of society, Worship of God, Education, Reproduction (POWER). From these, reason derives secondary precepts. He also taught real vs apparent goods and the doctrine of double effect.

Primary precepts

Fletcher: situation ethics

Joseph Fletcher (Situation Ethics, 1966) makes agape (selfless love) the only absolute; every rule can be broken if love demands it.

• Four working principles: pragmatism, relativism, positivism, personalism.
• Six fundamental propositions, e.g. love is the only intrinsic good, and love and justice are the same thing.

It is teleological — the loving outcome decides the act.

Agape

Aristotle: virtue ethics

Aristotle (Nicomachean Ethics) asks not "what should I do?" but "what kind of person should I be?" The goal is eudaimonia (flourishing).

• Virtue is a mean between two vices — e.g. courage lies between cowardice and rashness.
• Moral virtues come by habituation; intellectual virtues by teaching.
• Phronesis (practical wisdom) guides us to the right mean in each case.

The golden mean

Comparing the theories

• Natural law: clear, universal precepts, but critics say it rests on a fixed human "purpose" and can seem inflexible.
• Situation ethics: flexible and compassionate, but critics say "do the loving thing" is vague and open to abuse.
• Virtue ethics: realistic about moral growth, but gives less guidance on specific dilemmas.

Which theory?

Whose theory is it?

Sort each feature into the theory it belongs to.

Theory to thinker

Match each theory to its key figure or idea.

The big ideas to know

In essays, apply all three to the same dilemma to show you understand them. Press Finish.