Natural Law

St. Thomas Aquinas sought to present a rational basis for Christian morality and was heavily influenced by Aristotle’s philosophy.

The meaning of ‘good’

Natural law is based on Aristotle’s idea that everything has a purpose, revealed in its design (or natural ‘form’) and that the fulfilment of the telos is the supreme ‘good’ to be sought. Thus, a ‘good’ pen is one which fulfils its purpose i.e. to write.

Natural law does not argue that morality should be based on reason alone but that human reason (given by God) was a starting point for morality. Thus, morality should be known primarily through reason and secondarily Christian revelation.

Final cause

Aristotle makes an important distinction between an efficient cause and a final cause. An efficient cause is the agent of change which brings about its effect – in other words, what we would normally term ‘the cause’. The final cause is the actual purpose of a thing. E.g. the final cause of a statue may be to be an attractive ornament. For Aristotle, everything has a final ‘good’, which is achieved by fulfilling the purpose for which it was designed – its final cause.

Natural law depends upon this distinction. It assumes (by whatever means employed) that the world is the creation of God and thus should reveal his ultimate purpose in creating it.

Aquinas says that human beings, since they are intelligent, are able to direct themselves and therefore take responsibility for knowing and doing what God intends for them. Thus, human reason is required to examine and follow the sense of purpose that God had given to the world by virtue of being its creator.

Primary precepts

Aquinas started by trying to work out what the purpose of human life was. He concluded that this was to:

• Live
• Reproduce
• Learn
• Live in an ordered society
• Worship God

Features of natural law

• Natural law is based on the religious conviction that God created the world, establishing in it a sense of order and purpose which reflects his will.
• If everything is created for a purpose, human reasoning in examining that purpose is able to judge how to act in order to conform to that purpose.
• The action itself can either be natural or unnatural and is judged on that basis. It does not depend on its moral justification on any results. Thus and act can be deemed morally good in itself, even if it brings about suffering. i.e. it is not teleological.
• Since natural law is based primarily of reason rather than revelation, it is in principle discoverable by anyone, regardless of religious orientation. For this reason it is universal and not culturally relative. i.e. it is not relative.

The cardinal virtues

The cardinal virtues represent the human qualities that reason suggests are required in order to live a moral life and achieve the final cause:

• Prudence
• Justice
• Fortitude
• Temperance

The role of reason

Reason is essential to natural law. Aquinas said “To disparage the dictate of reason is equivalent to condemning the command of God.” Thus, humans should not be enslaved by following irrational impulses and desires. Reason is the supreme human virtue which sets us apart from animals.

Criticisms of natural law

• How do we know what is natural? Should we judge according to physical laws? Then, is it wrong to attempt to prolong the life of a dying man?

• What happens when there is conflict between revealed commands and the dictate of reason? For example, Jesus said turn the other cheek but natural law commands that you should attempt to preserve your life.

• If either of the presumptions that we are (i) rational beings and (ii) live in a world created by a God who has an ultimate purpose to his creation is challenged then that argument becomes invalid.

• Natural law seems inconsistent with the story of The Fall. Genesis 3 tells us that human reason was separated from God through sin. Thus, if our reason is corrupt then how can we deduce God’s purpose?