This document provides an overview of Thomas Aquinas' concept of natural law ethics. It defines natural law as the eternal law that is made known to human reason. Natural law is part of God's eternal law for creation and directs humans toward their final end of perfect beatitude in God. Positive laws enacted by humans must be in accordance with natural law. Natural law is universal and unchanging, while positive laws can vary over time and place. The natural law directs humans to preserve their being by doing good and avoiding evil like suicide and murder. Reason can deduce what is good or evil through applying natural law principles to specific situations. A law must serve the common good, be reasonable, and be promulgated by legitimate

1. Ethics GE107
Lesson 3: St. Thomas’ Natural Law Ethics
Introduction
Thomas Aquinas’ concept of law is an example of the application of Aristotelian
teleology to the integral theory of ethics, law and governing. Aquinas’ concept of natural law is
called moral law by many scholars. Man is able to anticipate the law of action in relation to eternal
law, and such participation in eternal law Thomas calls natural law. The ethics starts from the
principle good is to be done and evil is to be avoided. This principle is the basis for the rest of the
ethical precepts concerning what is to be done and what is to be avoided. Man has innate general
orientations on how to live and behave in this world. Conscience evaluates and judges the motives
and moral qualities of actions. This is the main idea of natural law, which is described in the article.
Objectives
Articulate what natural law ethics is
Apply natural law ethics
Meaning of Natural law and other law
Based on the phrase “Natural Law,” what is ethical is what the natural law says. What
is natural law? Natural law is the “ordinance of Divine Wisdom, which is made known to us by
reason and which requires the observance of moral order.” It may also be defined to be “The eternal
law as far as it made known by human reason.” By the eternal law we mean all that God necessarily
decrees from eternity. That part of the eternal law which reason reveals as directive of human acts,
we call the natural law.
Eternal law is what God wills for creation. We are part of God’s creation and so we are
part of Gods eternal law. We may not be able to understand the eternal law fully given our
limitations. However, by reason we have a grasp or a sense of the eternal law. This is natural law.
St. Thomas Aquinas wrote:
There is in man an inclination to good, according to the nature of his reason, which nature
is proper to him; thus man has a natural inclination to know the truth about God, and to live in
society; and in this respect, whatever pertains to this inclination belongs to the natural law; for
instance to shun ignorance, to avoid offending those among whom one has to live, and other such
things regarding the above inclination. (Summa Theologiae1-2 Question 94, Article 2)
Let us relate natural law to other kinds of law:
Rev. Charles Coppens, S.J. explains the various kinds of law according to St. Thomas:
A law decreed by Almighty God is a divine law; one established by man is a human law.
Those laws for human conduct which God, having once decreed creation, necessarily enacts in
accordance with that decree, constitute the natural law; those which God or man freely enacts
are positive laws. Now, between the natural law and positive laws, there are these four points
of difference:
l. The natural law, unlike positive laws, does not depend upon the free will of God; its
requirements flow from the intrinsic difference between right and wrong, which is determined by

2. Ethics GE107
the very essences of things. Hence, under this law, certain acts are not evil primarily because they
are forbidden, but they are forbidden because in themselves they are evil.
2. Consequently, the natural law is the same at all times, in all places, and for all persons;
but this is not true of positive laws, which may be changed with changing circumstances, or, if the
law-giver so wills it, even without change of circumstances.
3. The natural law emanates from God alone; but positive laws may be enacted by men.
4. The natural law is promulgated through the light of reason; positive laws require for their
promulgation a sign external to man.
In summary, we have an eternal law, God's law for the whole creation, which we cannot
fully grasp given our limitation. But with our gift of reason we have a grasp of that eternal
law, that is natural law. Divine law is decreed by God while human law is decreed by man.
Natural Law as a Universal Formula
As an ethical framework, the natural law or maxim may be applied as implicitly illustrated in
the following:
A universal formula which contains in brief an expression of the whole natural law is this:
"Keep the moral order, " or "Observe right order in your actions." Some writers state it simply as,
"Do good and avoid evil. " Now, the right order of human acts consists evidently in their proper
direction to man is last end, which is, subjectively, his perfect beatitude and, objectively, God
Himself. God must direct His free creatures to their last end, hence He commands them to observe
the moral order and forbids them to depart from it.
So what is natural and ethical for a human person is to "keep the moral order, to "observe
right order," to "do good and avoid evil" to preserve his/her being. Suicide and murder work
against preservation of human life, therefore, are a violation of the natural law.
St. Thomas Aquinas grounded the directedness of nature in God. All of creation is directed
toward their final end God, God Himself. To direct us to Himself, He gave the divine law. The
divine law given to us in the Ten Commandments of the Old Testament and the new commandment
of "love God and "love your neighbor. " by Jesus Christ in the New Testament, and in the we were
St. Thomas synthesized faith and reason. He believed that natural law is part of the divine law,
that the "natural law shares in the eternal law." All of creation is directed analogous to logical
reasoning, it may be applied as follows: Premise: Stealing is immoral and an evil to avoided.
Second Premise: The act of taking someone's property without his consent is stealing. Conclusion:
Therefore, the act of taking someone's property, which I actually intend to do, is immoral and an
evil to be avoided, which I should do avoid.
Law Defined
St. Thomas explained that the natural law is promulgated through the light of reason.
Positive laws require for their promulgation sign external to man. Laws that are enacted are called
positive laws. St. Thomas defined law in general as "an ordinance of reason which is for the
common good, and has been promulgated by one having charge of the community." For a law to
be a law, it must have the four requisites, namely, a) ordinance (order, command) of reason, b) for
the common good, c) promulgation, and d) by one who has charge of the community. Based on
the definition, an unreasonable law is not law; a law that favors one to the prejudice of another or

3. Ethics GE107
does not equally protect all is not a law; a law that is not promulgated or published or made known
to all, is not a law; and a law that is enacted by unauthorized persons is not a law.
A Law must be a product of reason not purely of emotion. When the heart rules the mind,
we can be highly unreasonable. A law is promulgated for the common good because we are meant
to be social, we belong to a community. A law that favors the male gender at the expense of the
female gender cannot be a law. A law must be promulgated by one whose primary task is to care
for his/her people, the community. The primary task of our lawmakers is to care for and protect
their people by legislating laws for the common good, The law must be made known or
communicated to all people to ensure correct understanding and compliance. A law that is
promulgated does not take effect immediately, In the Philippines, laws take effect after fifteen
days following the completion of the publication in the Official Gazette or a newspaper of general
circulation unless it is otherwise provided.
(https://batasnatin.com/law-libraray/ciyil-law/persons-and-family/82effectivity-of-laws.html,
Retrieved 6-18-19)