Aquinas’ Theory of Natural Law

Based on two fundamental authorities:

a. The Bible;

b. Aristotle.

Aquinas rejected Plato’s idea of the physical world being unimportant and shadowy –

Instead he followed Aristotle who claimed that the world is real and important.

Natural Law = “God’s order set within the parameters of the universe”

For Aquinas, morality is:

ACCESSIBLE THROUGH THE NATURAL ORDER

UNIVERSAL/

RELEVANT TO ALL SITUATIONS

UNCHANGING AND FOR ALL TIME

GIVEN BY GOD

ACCESSIBLE TO ALL…

WHETHER OR NOT THEY BELIEVE IN GOD

Aquinas’ basic moral law:

“Good is to be done and pursued…and evil is to be avoided.

All the other precepts of the law of nature are based on this.”

Aquinas’ message: DO GOOD AND AVOID EVIL

How can we know natural law?

1. Through revelation:

e.g. Paul’s Letter to the Romans. Paul asks why Gentiles obey laws from the Torah, when they’ve never heard of it.

God gave us two laws:

i. the Torah for Jews;

ii. Natural Law for Gentiles.

2. Through human reason:

a moral life is a life lived according to reason. An immoral life is one lived at odds with reason.

Reason tells us that the ultimate purpose or telos of human life = fellowship with God.

•Romans 2. 14-15:

“When Gentiles, who do not possess the law, do instinctively what the law requires, these, though not having the law, are a law to themselves. They show that what the law requires is written on their hearts, to which their conscience also bears witness.”

Aquinas’ ideas of purpose and perfection

1.The perfection of creation

•God = Creator•God = changeless and consistent.•God = good

Natural law regulates everything in creation, and so reveals God’s nature.

CREATION MUST BE GOOD BECAUSEGOD CANNOT CREATE ANYTHING

CONTRARY TO HIS NATURE

FOLLOWING NATURAL LAW IS THE WAY HUMANS CAN SHARE IN GOD’S ETERNAL NATURE.

2. Primary and secondary precepts

• Aquinas agreed with Aristotle that eudaimonia is our natural telos.

• Then he added a moral dimension – happiness can only be achieved by pursuing certain good actions.

• He also believed that eudaimonia = achieving union with God.

• In order to achieve eudaimonia, Aquinas said that humans must follow certain natural laws or precepts.

• The most important of these is

SELF PRESERVATION

• Primary precepts are required to ensure self-preservation:

REPRODUCTION

EDUCATION

PEACEFUL SOCIETY

WORSHIP GOD

• Secondary precepts set out the way in which the primary precepts can be put into practice.

EXAMPLE:

PRIMARY CONCEPT: REPRODUCTION

PURPOSE OF HUMAN GENITALS = REPRODUCTION

MASTUBATION AND HOMOSEXUALITY

NO NEW LIFE, DON’T FULFILTELOS, DON’T GLORIFY GOD

PRIMARY PRECEPTS ARE DESCRIPTIVE; SECONDARY

PRECEPTS ARE PRESCRIPTIVE.

Aquinas’ Four Types of LawNatural law is not the only law – according to Aquinas, there are four kinds:

ETERNAL LAW DIVINE LAW

NATURAL LAW HUMAN LAW

The Four Causes

• Aquinas borrowed Aristotle’s idea of different causes.

• Humans can work out what is good by working out the different causes.

• Humans need to use their reason for this

1. The Material Cause

2. The Efficient Cause

3. The Formal Cause

4. The Final Cause

Real and Apparent GoodsAquinas believed that:

HUMAN NATURE IS ESSENTIALLY GOOD

NATURAL LAW IS WITHINEVERYONE

HUMANS NATURALLYSTRIVE FOR PERFECTION

HUMANS WOULD NEVERKNOWINGLY PURSUE

EVIL

WHEN PEOPLE DO CHOOSEEVIL, THEY ARE FOLLOWING

AN APPARENT GOOD

IT’S JUST AN ERROR OF JUDGEMENT

USING OUR REASONHELPS US TODISTINGUISH

BETWEEN REAL ANDAPPARENT GOODS.

Reason identifies 4 natural or cardinal virtues:

PRUDENCE TEMPERANCE

FORTITUDE JUSTICE

The Bible reveals 3 more virtues: faith, hope and charity

Aquinas also identified 7 vices or cardinal sins which lead people

away from Natural Law.

• PRIDE• AVARICE• LUST• ENVY• GLUTTONY• ANGER• SLOTH

• Develop the virtues.• Eliminate the vices.• Requires practice.• Virtues should

become habitual.

Exterior and interior acts

• For Aquinas, both the intention and the act are important.

• To act in a good way for the wrong reason is to perform a good exterior act but a bad interior act.

Example 1:

• I help an old lady across the road.

• I do it to impress someone.

GOODEXTERIOR

ACT

BADINTERIOR

ACT

Example 2

• I steal money.

• I give the money to a friend in need.

BAD EXTERIORACT

GOODINTERIOR

ACT

• According to Aquinas, the theft of the money is not made good by my intention to help my friend.

• Acts are intrinsically good or bad.

• When humans act in accordance with their telos, God is glorified.