Natural law claims that everything has a purpose designed by its creator, and this purpose is what is intrinsically good. The concept has its roots in ancient Greek and Roman philosophy as described by thinkers like Aristotle and Cicero. Thomas Aquinas was a major proponent of natural law in the 13th century. He argued that natural law is derived from human reason and aims toward the highest good of God. Natural law theory proposes that there are fundamental moral principles knowable by reason, including prohibitions against murder, theft, and deception. However, critics argue that natural law faces challenges in accounting for concepts like homosexuality, contraception, and evaluating actions based on their consequences rather than intrinsic nature alone.

1. AS Level- Natural Law. Aquinas Grammar
What is natural Law?
• Natural law claims that everything is created to a particular design and for a
particular purpose, and that purpose is what is ‘good’ to which everything
aims.
-“Good is to be done and evil is to be avoided” (Aquinas)
What are the historical roots of natural law?
• Can be found in the ancient Greek and Roman world.
• Roman lawyer Cicero formulated the classic description of natural law in his
work On the Republica. In this he says
- True law is right reason in agreement with nature; it is of universal application, unchanging
and everlasting.
- (They will not be) different laws now and in the future, but one eternal and unchangeable law.
- (There will be) one master and ruler, that is, God, over us all.
What are the Teachings of Aristotle?
• Rooted in the philosophy from the 4th
Century.
• He believed that everything in life has a telos (purpose) and as such
differentiated between efficient causes and final causes:
1. Efficient cause- getting something done (opening a bottle)
2. Final cause- the end product (the bottle opened)
• While law changes from place to place, Natural law is always the same and
applies to everyone
• In the middle ages theologians argued that this principia ethica, understood
that the law that govern human conduct must lead to the highest good, that
being God.
Gemma Mulhern 13J

2. AS Level- Natural Law. Aquinas Grammar
What are the Teachings of Aquinas?
• Most famous exponent of the natural law
• 13th
Century
• Central feature of Catholic moral teachings
• He developed Aristotle’s ideas and argued that the natural telos of the world is
found in God.
• Wrote Summa Theologica
• His ethical theory is absolutist and deontological(focuses on the ethnicity of
actions) actions are intrinsically write or wrong.
• Believed that both intention and act are important.
• Acts are intrinsically (basically) good or bad
• In summa theological , Aquinas described natural law as a ‘moral code of
existence,’ created by God
• All Primary Precepts relate to the purposes and are derived from reason-do
not kill, do not lie, do not steal
Examples of Natural Law in Action in Modern Society:
Gemma Mulhern 13J
Primary Precepts
Preserve life
Live in society
Educate Children
Reproduce
Worship God
Secondary Precepts
Do not commit Murder
Do not abort an Unborn child
Defend the Defenceless
Do not commit Suicide
PLERW MUDS

3. AS Level- Natural Law. Aquinas Grammar
• The natural telos of sex is to procreate and anything that prohibits (stops) this
natural outcome is seen as a barrier to the fulfilment of the sexual telos
therefore contraception is wrong. Examples of contraceptive methods that
stops procreation occurring are Condoms and the morning after pill. Although
the natural law fails to acknowledge situations where contraception could
benefit to prohibit continued AID’s. But the Catholic Church argues that sex
outside marriage should not happen outside marriage and why should they
change their view on natural law being universal to suit the minority.
• If a couple is unable to have children does this make their relationship
unnatural, should they be having sex, does natural law condone rape?
• What if homosexuality proves to be genetic, will it then be accepted as
natural?
Strengths of Natural Law?
 Guidance on day-to-day questions
 Clear and defined so it could be applied universally
 Prevents one being treated as a means to an end
 Enables people to establish common rules in order to structure communities
 Based on reason so all people know what is right and wrong in themselves
 Attractive in a world that suffers from intercultural strife and disharmony
Problems with Natural Law?
 We all have the ability to do good but are often driven by selfish desires in a self-
centred world.
 What is homosexuality was deemed to be genetic, would it then become natural
 Today, the human body is seen as a whole living organism that works together, not
the fragmented collection of parts that Aquinas seems to believe in.
 Peter Vardy and Paul Grosch challenge Aquinas. They believe that it isn’t
necessary that every discharge of semen should produce a new life. What about
the benefits to the couple’s relationship.
 Peter Vardy and Paul Grosch also argued that Aquinas’ theory is wrong as the
human body is not a set of fragmented parts but one organ working together.
Gemma Mulhern 13J

4. Actions are
moral
consequences
Based on the
law of nature
Based on ideal
that God created
the world and
established order
to bringing
everything to
fulfilment
Based on
human
reason, not
religious
beliefs
A clear out
theory that
applies to
everyone
We all have the
capacity of
reason; therefore
can find a good
way to live with
reason in relation
to natural law
Contains
basic and
fundamental
Laws
Features
of
Natural
Law
AS Level- Natural Law. Aquinas Grammar
Gemma Mulhern 13J

5. AS Level- Natural Law. Aquinas Grammar
Critical Analysis…
‘The natural is that which everywhere is equally valid.’ (Aristotle)
‘Good is to be done and evil is to be avoided.’(Aquinas)
‘Moral code which human beings arte naturally inclined towards.’(Vardy)
‘The Natural law is written and engraved in the soul of each and every man.’ (The catechism of
the Roman Catholic Church)
‘The natural law is nothing other than the light of understanding placed in us by God.’
(Aquinas)
‘The term natural law refers to the prescription laws as derived by human nature as opposed to
the descriptive laws of Nature’ (Jenkins)
Gemma Mulhern 13J

6. AS Level- Natural Law. Aquinas Grammar
‘The Moral life is the life according to reason’ (Summa Theologica)
‘The natural law is written and engraved in the soul of each and every man, because it is
human reason ordaining him to do good and forbidding him to sin’ (Leo XIII)
‘There will be one master and ruler that is God’ (Cicero)
Glossary
• Deontological- the theory of our duties. It places a sense of duty over what is naturally.
It is when you are not worried about the outcome. They know if the act is right or wrong
but contain it anyway. For example, having sex outside of marriage.
• Deduce- reach by reasoning from evidence.
• Intrinsic-essential to the basic nature of something
• Apprehend- arrest and take into custody; grasp or understand
• Precept- rule of behaviour
• Telos- purpose
• Disparage- speak contemptuously
• Inclination-liking, tendency or preference
• Virtue-moral goodness; positive moral quality
Gemma Mulhern 13J

7. AS Level- Natural Law. Aquinas Grammar
‘The Moral life is the life according to reason’ (Summa Theologica)
‘The natural law is written and engraved in the soul of each and every man, because it is
human reason ordaining him to do good and forbidding him to sin’ (Leo XIII)
‘There will be one master and ruler that is God’ (Cicero)
Glossary
• Deontological- the theory of our duties. It places a sense of duty over what is naturally.
It is when you are not worried about the outcome. They know if the act is right or wrong
but contain it anyway. For example, having sex outside of marriage.
• Deduce- reach by reasoning from evidence.
• Intrinsic-essential to the basic nature of something
• Apprehend- arrest and take into custody; grasp or understand
• Precept- rule of behaviour
• Telos- purpose
• Disparage- speak contemptuously
• Inclination-liking, tendency or preference
• Virtue-moral goodness; positive moral quality
Gemma Mulhern 13J