1. Thomas Aquinas
13th-Century scholar in the Dominican order 1

2. Thomas Aquinas 13th-Century scholar in the Dominican order
Incorporates rediscovered Aristotelian concepts and principles into Catholic doctrine 2

3. Thomas Aquinas 13th-Century scholar in the Dominican order
Incorporates rediscovered Aristotelian concepts and principles into Catholic doctrine
Christian Aristotelianism ≠ Aristotle 3

4. Thomas Aquinas: Summa Contra Gentiles
One of two major works (also: Summa Theologica) 4

5. Thomas Aquinas: Summa Contra Gentiles
Human action
Every action aims at some end.
Every agent acts only for ends befitting to the agent.
What is befitting to a thing is good for it.
Therefore, every action aims at some good. 5

6. Thomas Aquinas: Summa Contra Gentiles
The end of human action
(“end” in the sense of “purpose,” not “conclusion”) 6

7. Thomas Aquinas: Summa Contra Gentiles
The end of human action
“The last end of man and of any intelligent substance is called happiness or beatitude, for it is this that every intellectual substance desires as its last end, and for its own sake alone.” 7

8. Thomas Aquinas: Summa Contra Gentiles
The end of human action
“The last end of man and of any intelligent substance is called happiness or beatitude, for it is this that every intellectual substance desires as its last end, and for its own sake alone.”
People disagree, however, about the nature of happiness. 8

9. Thomas Aquinas: Summa Contra Gentiles
The end of human action
“The last end of man and of any intelligent substance is called happiness or beatitude, for it is this that every intellectual substance desires as its last end, and for its own sake alone.”
People disagree, however, about the nature of happiness.
Aquinas's view: Man's ultimate happiness consists in the contemplation of God. 9

10. Thomas Aquinas: Summa Contra Gentiles
Not pleasure -- or even virtue 10

11. Thomas Aquinas: Summa Contra Gentiles
Why happiness does not consist in pleasure 11

12. Thomas Aquinas: Summa Contra Gentiles
Why happiness does not consist in pleasure
Pleasure exists for the sake of operation.
Man's ultimate happiness is something that exists for its own sake.
Therefore, happiness does not consist in pleasure. 12

13. Thomas Aquinas: Summa Contra Gentiles
Why happiness does not consist in acts of virtue
All moral activities are directed toward something else. 13

14. Thomas Aquinas: Summa Contra Gentiles
Why happiness does not consist in acts of virtue
All moral activities are directed toward something else.
Example: Courage in war is directed toward the end of victory and peace. 14

15. Thomas Aquinas: Summa Contra Gentiles
Why happiness does not consist in acts of virtue
All moral activities are directed toward something else.
Example: Courage in war is directed toward the end of victory and peace.
Ultimate happiness cannot be directed toward a further end.
Therefore, happiness does not consist in acts of virtue. 15

16. Thomas Aquinas: Summa Contra Gentiles
So: True happiness is… 16

17. Thomas Aquinas: Summa Contra Gentiles
True happiness:
“Man's ultimate happiness consists in the contemplation of truth.”
As Aristotle claimed, happiness consists of contemplation of the highest object.
The highest object of contemplation is God.
Therefore, man's ultimate happiness consists in contemplation of God. 17

18. Thomas Aquinas: Summa Contra Gentiles
If true happiness consists in contemplation of God, then the good life does not consist in virtue – however virtue may be an instrument in the good life. 18

19. Thomas Aquinas: Summa Contra Gentiles
If true happiness consists in contemplation of God, then the good life does not consist in virtue – however virtue may be an instrument in the good life.
Prudence
Justice
Temperance
Fortitude 19

20. Thomas Aquinas: Summa Contra Gentiles
If true happiness consists in contemplation of God, then the good life does not consist in virtue – however virtue may be an instrument in the good life.
Prudence
Justice
Temperance
Fortitude
Also:
Faith
Hope
Charity 20

21. Thomas Aquinas: Summa Contra Gentiles
If true happiness consists in contemplation of God, then the good life does not consist in virtue – however virtue may be an instrument in the good life.
Through Christian virtues, we can understand the natural law 21

22. Thomas Aquinas: Summa Contra Gentiles
If true happiness consists in contemplation of God, then the good life does not consist in virtue – however virtue may be an instrument in the good life.
Through Christian virtues, we can understand the natural law (reason applied to nature – a discovery process) 22

23. Thomas Aquinas: Summa Contra Gentiles
If true happiness consists in contemplation of God, then the good life does not consist in virtue – however virtue may be an instrument in the good life.
Through Christian virtues, we can understand the natural law (reason applied to nature – a discovery process)
Human law is only valid if it conforms to natural law. If a law is unjust, then it is not actually a law, but is a "perversion of law" 23