The theory of natural law is the view that
moral values are fixed features of the universe which all humanity
can discover through reason. Strictly speaking, according to natural
law theorists, there is only one highest principle of natural
law (such as "we ought to be sociable"). Subsidiary
moral rules and civil laws are derived from this (such as "we
ought not murder"). These subsidiary rules carry the force
of natural law to the degree that they are necessary for the fulfillment
of the highest obligation. Natural law theorists differ as to
whether the highest natural law is (a) a feature of God's reason,
(b) created by God's will, or (c) a Platonic-like value independent
of but co-eternal with God. In any case, it is eternal insofar
as it is distinct from both human-created laws (such as "drive
only on the right hand side of the road"), and provisional
divine mandates (such as "don't eat pork").
Natural law theory has its roots in ancient
Greek thought, particularly Stoicism. According to Stoicism, the
world is governed by a rational principle, the logos, and our
obligation is to live according to this principle. The term "natural
law" (ius naturale) appears sporadically in discussions
of Roman law, in which it is a category of law distinct from civil
and human law. However, the term gains prominence in early Christian
thought and gains its fullest medieval expression in Thomas Aquinas.
For Aquinas, natural law is a special subset of the divine law
which pertains to moral behavior, and is accessible to everyone
through reason -- including unbelievers. Aquinas argued that the
highest principle of natural law is that "we ought to do
good and avoid evil." As suggested by Aristotle, we discover
what is "good" by looking at our purpose as humans.
An inspection of our purpose, then, informs us that we are to
perpetuate the species, preserve our lives, live in society, and
worship God. From these we generate secondary moral principles
which carry the force of natural law. It is the job of wise people
to deduce more particular tertiary principles from these, such
as don't steal, which also carry the force of natural law. Although,
for Aquinas, the obligatory force of natural law arises from God's
will, natural law is essentially an expression of God's reason.
This position is called intellectualism. For other medieval
philosophers, such as Duns Scotus (1266-1308), and William of
Ockham (1285-1349), natural law is completely a creation of God's
will. This position is called voluntarism, and has the
unfortunate consequence that God could will whatever he wants,
even the exact opposite of present moral values. The Dutch humanist
Hugo Grotius (1585-1645) offers an alternative position in his
landmark On the Law of War and Peace (De jure belli
et pacis, 1625). Grotius implies that natural law is an eternal
Platonic-like truth which exists independently of God:
The law of nature, again, is unchangeable
-- even in the sense that it cannot be changed by God....Just
as even God, then, cannot cause that two times two should not
make four, so he cannot cause that that which is intrinsically
evil be not evil.
Influenced by Grotius, Thomas Hobbes offered
a purely positivist (or human-created) account of natural law.
To escape from the brutal state of nature, selfish humans agree
(or contract) to give up their more unsociable freedoms in exchange
for peace. The rules of the contract, for Hobbes, are "laws
of nature." Although these laws are created by participants
in the contract, he notes that they are "immutable,"
although in quite a different sense than traditional natural law
theorists maintain:
The Laws of Nature are immutable and eternal.
For injustice, ingratitude, arrogance, pride, iniquity, acception
of persons, and the rest, can never be made lawful. For it can
never be that war shall preserve life, and peace destroy it.
Samuel von Pufendorf (1632-1694) was one of
the last great philosophers in the natural law tradition. In his
Law of Nature and Nations (De Jure Naturae et Gentium,
1762), Pufendorf argues that individual humans are vulnerable,
and we must live in society to survive. Accordingly, God, as our
creator, wills that we should be sociable, and this becomes the
highest natural law. Our moral duties arise from this mandate
and, in turn, these moral duties lead to civil and international
laws. Later moral and political philosophers borrowed heavily
from Grotius and Pufendorf, such as John Locke, Samuel Clarke,
and William Paley. However, the original theory ultimately lost
viability as reflected in Bentham's comment that "Right ...
is the child of law; from real laws come real rights; but from
imaginary laws, from laws of nature, ... come imaginary rights"
(Anarchical Fallacies, ed. John Bowring, Vol. 2, p. 220).
Internet Encyclopedia of Philosophy,
© 1997