natural law

Everything has a purpose

Ethics is the struggle to determine what is right or wrong, or ‘good’ and ‘bad’.  Some ethical theories are hedonistic – they say that pleasure (and the absence of pain) are the only ultimately ‘good’ ends towards which to aim.  Some Christian ethicists argue that following God’s will – as revealed through prayer, scriptures and prophecy – is the ultimate good.

The theory of Natural Law was put forward by Aristotle but championed by Thomas Aquinas (1225-74). Natural Law has elements of both of these approaches. Man desires happiness, but for Aquinas this means fulfilling our purpose as humans. He said, in Summa Theologica, "whatever man desires, he desires it under the aspect of good." Fulfilling our purpose is the only ‘good’ for humans.

We will see that Aquinas first asks what our human nature is, and then looks at the rules that can be derived from this.

The purpose of humans - the Primary Precepts

There is a single guiding principle that sums up our nature:

"good is to be done and pursued, and evil is to be avoided." All other precepts of the natural law are based upon this.

Aquinas looks at what is 'good' for humans, saying that humans share part of their nature with all natural things, part with animals, and part of our human nature is particular to us. Aquinas said:

• inasmuch as every substance seeks the preservation of its own being... whatever is a means of preserving human life , and of warding off its obstacles, belongs to the natural law
• those things are said to belong to the natural law, "which nature has taught to all animals" [Pandect. Just. I, ***. i], such as sexual intercourse, education of offspring and so forth
• man has a natural inclination to know the truth about God, and to live in society

Although textbooks talk of five Primary Precepts, and some resources on this site reflect this, Bernard Hoose revealed, over lunch at an Ethics conference, his frustration with this tendency. He felt there were only three, as can be seen above. Read Summa Theologicayourself, and you may feel that Aquinas is not giving an exhaustive list, but simply some examples of "self evident principles" perceived by reason.

A mnemonic for these might be PREGS:

• Protect and preserve human life
• Reproduce and Educate your offspring
• know God and live in Society

Teleology and Deontology

In 1930, CD Broad contrasted teleology and deontology in an attempt to categorise ethical theories. By teleology, he meant theories where "the rightness or wrongness of an action is always determined by its tendency to produce consequences which are intrinsically good or bad". According to Broad, deontological theories hold that "such and such a kind of action would always be right (or wrong) in such and such circumstances, no matter what its consequences might be". In essence, teleology is concerned with good and bad, deontology with right and wrong.

This distinction, and these definitions, are seen by many ethicists as…