NB: All previous chapters can be found here.
It seems appropriate at this point to review Natural Law through a Catholic lens. Now, I know one might suggest that this is what I have been doing via my extensive review of the work of Aquinas. Well, yes and no. I have worked through this given my own understanding of his thought; but it seems to me that there is value in testing out how well this review conforms to what might be called a much more well-informed analysis.
While I know many will disagree with the many references toward God (what do you expect from a Catholic source?), I suggest that in those instances, just check to see how consistent the point is with Aristotle.
According to St. Thomas, the natural law is "nothing else than the rational creature's participation in the eternal law" (I-II.91.2). The eternal law is God's wisdom, inasmuch as it is the directive norm of all movement and action. When God willed to give existence to creatures, He willed to ordain and direct them to an end.
Man is destined toward this end, and receives from God a direction toward this end. The law, accordingly, is placed in man – in his nature. Of course, given intelligence and free will, man – unlike all other beings – has a say in his conduct.
Those actions which conform with its tendencies, lead to our destined end, and are thereby constituted right and morally good; those at variance with our nature are wrong and immoral.
The word “good” is worth better understanding. In the Greek, there were many different words that we translate to “good.” We have retained the different meanings but all in one word, but can understand these only in context.
For example, a tool or instrument is good if it is an efficient means toward obtaining a desired end; alternatively, something is good if approaches the perfection proper to its nature. In one way or another, the word can be seen to mean “desirable.” I consider it in the context offered by Plato – the Form of the Good, that is the ideal, the perfect.
Returning to natural law:
Radically, the natural law consists of one supreme and universal principle, from which are derived all our natural moral obligations or duties.
The authors identify many erroneous opinions regarding the fundamental rule of life: Bentham and utility; Fichte, who taught to love self above all others; Epicurus, to follow nature; the Stoics, to live according to reason. Catholic moralists find something else – something from which some germ of which exists in these others, but that is necessary to properly understand all others:
"Love God as the end and everything on account of Him"; "Live conformably to human nature considered in all its essential respects"; "Observe the rational order established and sanctioned by God"; "Manifest in your life the image of God impressed on your rational nature."
As mentioned, if this is too heavy with “God,” for you, just consider as the context Aristotelian metaphysics and the implications for human behavior. At least in action, you will end up in pretty much the same place.
Thomas offers a deeply philosophical exposition, based on a simple premise:
…the supreme principle of moral action must have the good as its central idea, [Thomas] holds that the supreme principle, from which all the other principles and precepts are derived, is that good is to be done, and evil avoided (I-II, Q, xciv, a. 2).
From this premise, all can be deduced. The result is a natural law that is both universal and immutable. It is also knowable by all men:
Founded in our nature and revealed to us by our reason, the moral law is known to us in the measure that reason brings a knowledge of it home to our understanding.
However, unaided by supernatural revelation, man’s knowledge of the law will be imperfect – in some cases terribly so:
In proof we need but recall that the noblest ethical teaching of pagans, such as the systems of Plato, Aristotle, and the Stoics, was disfigured by its approbation of shockingly immoral actions and practices.
Which brings us full circle to the connection of natural law to the “pagans,” the earlier Greek philosophers and others – God placed this law in the hearts of all men, and men have been searching for Him who placed the law in their hearts.
Logically, chronologically, and ontologically antecedent to all human society for which it provides the indispensable basis, the natural or moral law is neither—as Hobbes, in anticipation of the modern positivistic school, taught—a product of social agreement or convention, nor a mere congeries of the actions, customs, and ways of man, as claimed by the ethicists who, refusing to acknowledge the First Cause as a Personality with whom one entertains personal relations, deprive the law of its obligatory basis. It is a true law, for through it the Divine Mind imposes on the subject minds of His rational creatures their obligations and prescribes their duties.