Aristotle believed that an object was only “good” if it fulfilled its purpose. For example, an acorn is only a good acorn when it produces a healthy, fruit bearing oak tree, or a knife is only good if it cuts well, as this is what its purpose is. This principle can be applied to humanity. Aquinas developed this by saying that humankind has several purposes set by God which we are supposed to dedicate our lives to. These are to live, to reproduce, to learn, to exist in an ordered society and to worship God. Primarily, humans are created to preserve the immortal self i.e. these purposes in life are in preparation for life beyond the grave.
“Reason is used to discover God’s intention and purpose of humanity
and this will enable one to arrive at the principles of natural law.”
(The Puzzle of Ethics)
Within the concept of natural law come the ideas of efficient and final cause. Natural law describes not only how things are but how they ought to be. The efficient cause is the agent which brings something about. For example, the person who creates a statue and the work he puts in which causes the statue to exist. It is what we normally call “cause.” The final cause, on the other is the reason behind the sculptor’s mind. Why did he carve at a particular point and at that angle? The answer is “in order to create a beautiful piece of art”. Final cause is the purpose or aim that explains why the sculpture is as it is. This ties in with natural law, as final cause is the purpose that objects or people need to fulfil in order to be good.
Aquinas’ version of these ideas from Aristotle is called “potentiality and actuality.” Potentiality is the potential something has to change to another object, e.g. a tadpole turning into a frog. Actuality is the way something actually is. For example:
“A healthy, educated man who has developed his conscience is better than one who is sick, ignorant or vicious.”
It is the same as fulfilling a purpose or final cause.
Aquinas believed that natural law worked on 4 different levels: Firstly, eternal law – the aim and plan in God’s mind which forms the universe are its purposes. Secondly, Divine law – a law given to the people by God through the church outlining how to live out their lives in order to fulfil their purpose. Thirdly, Natural law – our instinctive sense of right and wrong, discovered with the use of observation and reason. Lastly, human law – laws which we set for ourselves to ensure we live in an ordered society. Aquinas believed that these laws work in a hierarchy order. Each level depends on the levels which are higher than them. Eternal law evidently depends on nothing, whereas human law depends on all three other laws above it. With this in mind, it could be said that it would be right for people to break to human law if it was accordance with divine law.
Although natural law is a very good way of life for people, it can also be seen to have some weaknesses. For example, it might be possible to argue that humanity may share some basic moral ideas, but these may not extend as far as generalities such as “killing is mainly wrong.” This raises the question “do humans have a common nature?” Also, natural law is based on God. Does this mean that an Atheist cannot believe in and practise natural law? Another weakness is that reason can be used to plan evil as well as good. This would mean that people could justify evil acts with the pretence using their natural instincts. Natural law can also contradict common sense in some cases. A major weakness with natural law is that we can never be sure what God’s purpose for humanity is, therefore, we can only guess how to achieve it and be good.
To conclude, natural law is an instinctive sense of right and wrong which is developed by the individual. It involves using God’s gift of reason to discover one’s purpose (efficient cause) and fulfil it in order to do good (final cause).
