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4.7: Summary and Review

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    Aquinas is an intellectual giant. He wrote an incredible amount covering a vast array of topics. His influence has been immense. His central idea is that humans are created by God to reason — that is our function. Humans do the morally right thing if we act in accordance with reason, and the morally wrong thing if we don’t.

    Aquinas is an incredibly subtle and complex thinker. For example, his Doctrine of Double Effect makes us to reflect on what we actually mean by “actions”, “intentions” and “consequences”. His work remains much discussed and researched and typically still plays a central role in a Christian Ethics that rejects Divine Command Theory.


    • Thinking that Aquinas is a Divine Command Theorist.
    • Thinking that Eternal Law is something that God decided to write.
    • Thinking that Natural Laws are laws of science — e.g. law of thermodynamics.
    • Thinking that all the “laws” are absolute.
    • Thinking that it is always morally required of us to follow secondary precepts.
    • Thinking that Aquinas is committed to there being only one set of secondary precepts for all people in all situations.


    1. If God exists then what — if anything — do you think that has to do with what is right and wrong?
    2. We might answer the “arbitrariness” dilemma by citing God’s nature. Why might this answer be problematic?
    3. What is the Eternal Law?
    4. What are Natural Laws and primary precepts?
    5. What are Human Laws and secondary precepts?
    6. What are Divine Laws?
    7. Just as a good eye is to see, and a good acorn is to grow then a good human is to…? Is to what? How are we going to finish this sentence?
    8. People often talk about what is “natural”? What do you think they mean by this? How useful is the notion of “natural” in a moral theory?
    9. Think of a descriptive claim. Think of a prescriptive claim. Why might it be problematic moving from one to the other?
    10. If people thought long enough, do you think there would be convergence on what is morally right and wrong?
    11. What is the Doctrine of Double Effect?
    12. What is the difference — if anything — between intending to bring about some end and acting where you know your action will bring about that end?


    Apparent goods

    A priori

    A posteriori

    Eternal Law

    External acts

    Natural Law

    Primary precepts

    Real goods

    Secondary precepts

    Internal acts

    Doctrine of Double Effect


    Aquinas, Thomas, Summa Theologica, freely available at

    ―, Romans (Commentary on the Letter of Saint Paul to the Romans)Plato, Euthyphro, translated by Benjamin Jowett, freely available at

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