The History of Natural Law
Key
elements of Natural law and Natural rights in Jurisprudence
The origins of natural law lie in the
thought of the philosophers and jurists of the ancient world. They were
convinced that there were rules for human behavior based upon objective, eternal
norms. They
conceived of these norms as having been established by nature and
human reason. The Romans were the first to coin the term “natural law”(ius naturale).
Medieval and early modern jurists and theologians (Catholic, Protestant, and
Jewish) found the idea of natural law attractive. It
was congruent with their conception of the universe and with their notions of
human psychology. Expanding upon and developing further the definitions of
natural law they found in the ancient sources, medieval jurists and theologians
placed natural law at the pinnacle of a hierarchy of laws that regulated and
guided human behavior. Their paradigm held sway in western jurisprudence until
the nineteenth century. Gratian
The Roman orator Cicero († 43 B.C.) summed up an important strand of ancient
thought when he argued in his De republica 3.22 that “true law was right reason
that was congruent with nature.” He concluded that “there was one eternal,
immutable, and unchangeable law” and that God had established it as the Emperor
and Master of all humankind.
Omnes gentes et omni tempore una lex et sempiterna et
immutabilis continebit, unus erit communis quasi magister et imperator omnium
Deus, ille legis huius inventor, disceptor, lator
(Cicero, De republica 3.22)
Later Christian thinkers incorporated Cicero’s
conception of law into their own thought. The ancient Roman jurists dealt with
two types of law that transcended the law of the Roman Empire, the law of
peoples (or nations) (Ius gentium) and natural law (Ius naturale). In the second
century A.D. the Roman jurist Gaius was the first to define the
Ius gentium as
having been established by the natural reason of all humankind (Institutes 1.1).
Later jurists did not always distinguish carefully between natural law and the
Ius gentium. This conceptual
ambiguity would long remain a problem of
jurisprudential and theological thought. In the third century the jurist Ulpian
defined natural law as what “nature teaches all animals,” including human
beings. He distinguished natural law from the Ius gentium that was common only
to human beings and established by their customary usages. He cited marriage and
the procreation of children as examples of natural law. Ulpian’s definition was
later included in the Emperor Justinian’s comprehensive codification (ca.
533-536) of Roman law (Digest 1.1.3).
Gratian
Introduction
Justinian’s codification also included a
introductory textbook for the study of law called the Institutes. The definition
of natural law in the Institutes moved the source of natural law from the
behavior of creatures to God: “Natural laws are established by divine providence
and always remain firm and immutable (Institutes 1.2.11).” A little later the
authors of the Institutes asserted that the Ius gentium is identical with
natural law (Institutes 2.1.11). In every European law school from the eleventh
to the seventeenth century, professors and students studied and pondered
Ulpian’s and the Institute’s definitions — and their contradictions.
Although some late antique Christian theologians mentioned natural law in their
writings, they did so infrequently. Natural law never became an important
concept in the theological thought of the early church fathers.
When Isidore of
Seville composed (ca. 620) his encyclopedic Etymologies (5.4) he combined the
two traditions that had circulated in the ancient world. He defined natural law
as being the law common to all nations that was established by the instigation (instinctus)
of nature, not by human legislation. Examples of natural law were marriage and
the procreation of children, “one liberty of all human beings (una libertas
omnium),” and the acquisition of property taken from the heavens, earth, and
sea.
From Isidore to the jurist
Gratian in the twelfth century there was virtually no
discussion of natural law as a norm for human society. As part of his plan to
bring order to the chaotic state of church law, Gratian
(ca. 1140) compiled a
legal collection of ecclesiastical norms. At the beginning of his canonical
collection, called the Decretum, he
discussed the various types of laws that
regulated and guided the behavior of human beings. In the opening sentence of
his collection Gratian brought natural law to the forefront of all future
discussions about the structure of all human law: “The human race is ruled by
two things, namely, natural law and customary usages. Natural law is what is
contained in the law (lex sic) and Gospels.” Gratian concluded that natural law
dictated that “Each person is commanded to do to others what he wants done to
himself,” connecting natural law with the biblical injunction to do unto others
what you would have them do unto you (Matthew 7.12). By defining natural law as
the duty to treat other human beings with care and dignity, Gratian stimulated
jurists to reflect upon a central values of natural law: the rendering of
justice and the administering of equity in the legal system. To define the
contents of natural law he placed Isidore’s definition of natural law on the
first page of his
Decretum (D.1 c.7). Together with the texts of Roman law in
Justinian’s compilation, Gratian’s Decretum became one of the standard
introductory texts for the study of law (the Ius commune) in European law
schools, and Isidore’s definition became one of the most important starting
points for all medieval and early modern discussions of natural law.
St. Thomas Aquinas
Medieval jurists and theologians found several natural laws in their sources.
During the twelfth century when the jurists subjected these definitions of
natural law to careful analysis, they brought out these contradictions. They
pointed out that natural law could be the natural instinctive behavior of all
God’s creatures. It could be the rules and norms of behavior that governed
primitive human beings before human societies established their own particular
laws. It could be the common sense of justice and equity that one could find in
all human laws. They also argued that human reason might be a source of
knowledge about the norms of natural law. It could be divine law. It could be
the Ius gentium.
The jurists discussed all these possible types of natural law and did not, at
first, give primacy of place to one. They distinguished between a natural law
that was established by nature and one that was established by the natural order
of the world. If nature can be said to create natural law, some jurists
concluded, then “nature is God” (natura, id est Deus). They did not embrace a
juristic pantheism but simply acknowledged that the word “nature” in this sense
could be used for the creator. The jurists who commented on Gratian’s Decretum
developed the most elaborate analysis of natural law. The most important of the
twelfth-century jurists, Huguccio (ca. 1190), located the origin of natural law
in human beings. Natural law is reason, and that reason is a natural power of
the soul (naturalis vis animi) that permits them to distinguish good from evil.
This reason is called “law”(ius) because it commands and “law” (lex) because it
binds. Huguccio also summed up twelfth-century juristic opinion on the force of
natural law in human affairs. Natural law, he observed, consisted of three
levels of authority: commands, prohibitions, and indications or declarations (demonstrationes).
An example of a command was the precept to “love your Lord God.” A prohibition
of natural law may be taken from the Ten Commandments, “Thou shalt not steal.”
The third level of natural law leads human beings to choose what is licit and
good over what is bad and evil. For example, in Gratian’s excerpt from Isidore
of Seville liberty is a state that should be granted to all human beings.
Huggucio noted, however, that all men are not free. Natural law leads men to
liberty but does not command it. Huguccio explained that although liberty has
its roots in natural law, God introduced slavery into the world because of human
sins. Although medieval thinkers had to confront Isidore’s elegant and stirring
maxim that expressed the basic norm of human freedom (una libertas omnium)
constantly, they could not overturn the institution of slavery that was endemic
in their world or undermine the rights of slave owners.
Medieval ideas about natural law were transmitted to the modern world primarily
through the vehicle of theology, especially the theology of
St. Thomas Aquinas
(ca. 1225-1274). Thomas treated natural law comprehensively in his Summa theologica in Book One, part two,
questions 91 and 94. His conclusions drew
heavily on the thought of the jurists. Natural law has its origins in human
nature. This nature is the same in all human beings. Reason is the foundation
upon which all natural law is based. The primary goal of natural law is to
direct human beings toward the good. Men follow the dictates of natural law in
three ways: following the order that exists in nature, obeying what nature has
taught all animals, and, finally, pursuing the inclinations and tendencies of
human reason. When Thomas asked the question “Can natural law be changed? (Summa theologica I-II q.94 a.5), he augmented the thought of the jurists when he
explained why some elements of natural law are immutable and some are not.
Natural law consisted of first principles that cannot be changed and secondary
principles that can be. Thomas explained how slavery could be justified
by noting that it did not arise from nature but from human reason for the
benefit of human life.
Elements of Natural Law in Jurisprudence
Natural law became an integral part of medieval legal and theological thought.
In private law the jurists used natural law in creative ways to justify and
regulate particular legal institutions. Twelfth- and thirteenth-century jurists
of the
Ius commune argued that property rights were protected by natural law
because when God forbade stealing, he sanctioned private property. Since natural
law protected private property, they concluded that even the emperor, king or
prince could not deprive a person of their property except for just and
necessary reasons. By the end of the twelfth century, the jurists included
contractual rights under the provisions of natural law. A contract was concluded
by oaths. Oaths were promises to God.
Consequently, they concluded that
private contracts were grounded in natural law. Even the prince was
bound by the contracts that he might make with his subjects or with other
princes. He may be sovereign but was not exempt from the precepts of natural law.
In the
fourteenth century the jurists argued that the
norms that governed judicial
procedure were also derived from natural law. Consequently every person had an
absolute right to be summoned, present witnesses, and have a public trial. In an
ingenious use of the story of God’s condemnation of Adam and Eve in Genesis
3.9-12, --- of which we will learn more later in the class --- the jurists decided that God had established the norms of procedure when
he conducted the first trial in the Garden of Eden. By the end of the Middle
Ages the Spanish theologian and jurist Francisco de Vitoria (1492-1546) put
forward the remarkable argument that the right of the majority of people to
render their consent in political matters was also a norm of natural law.
Back to
Definitions Law
508
In this short and far from complete catalogue of rights that theologians and
jurists grounded in the norms of natural law, an important point must be
emphasized. In some cases, like the norms of procedure, they found
justifications for their arguments in sacred scripture. In others, like the
inviolability of contracts, they could discover no precedents in sacred
scripture. Instead they relied on norms that had evolved in the Ius commune.
These norms conformed to reason, reason so compelling that they expressed
eternal truths, Huguccio’s and Aquinas’ “the reason of natural law.”
By the end of the Middle Ages jurists and theologians had reached general
agreement about the structure and content of natural law. Gradually these ideas
about natural law migrated from the Ius commune into the customary, local legal
systems of Europe, and jurists incorporated natural law into their discussions
of local customary law. The thirteenth-century commentary on English law that
circulated under the name of “Bracton” borrowed word for word the definitions of
natural law from the jurists of the Ius commune. Bracton’s discussion of natural
law did not bear fruit in English legal thought until the fifteenth and
sixteenth century, but the seeds of a natural law tradition in the common law
were planted early.
The Iberian legal compilation, Las siete partitas, published during the reign of
Alfonso X the Wise (1221-1284), devoted the second title of book one to natural
law and the Ius gentium. This summary of natural law and its handmaiden, the Ius
gentium, also reflected the thought of the jurists. Natural law governs all men
and animals. Its precepts regulate the institutions of marriage and the raising
of children. The Ius gentium is law that is common for all men but not animals.
Its two fundamental principles are the rights of property and self-defense.
These two laws, the compilers stated, inform all the ordinances that deal with
those issues in this law book. Gregorio López de Tovar (ca. 1496-1560) wrote an
extensive commentary on Las siete partidas in the sixteenth century. He
emphasized that Aquinas’ natural reason was fundamental for knowing and
understanding the contents of natural law. “Natural reason ‘inclines’ human
beings to marry.” Marriage is, therefore, founded on natural law. Even the
natives in the new world have a true marriage because natural reason instigates
them to form this bond. By the end of the Middle Ages the support, education,
and inheritance of children were generally considered to be precepts of natural
law, and López made the point that a child’s right of inheritance could not be
taken away by contract or custom. Spanish thinkers in the sixteenth and
seventeenth centuries made significant contributions to the development of
natural law thought.
Medieval natural law provided the basis of all discussions of natural law in
early modern juristic and philosophical thought. When Thomas Jefferson wrote in
the Declaration of Independence that “We hold these truths to be self-evident,
that all men are created equal, that they are endowed by their Creator with
certain unalienable rights, that among these are life, liberty, and the pursuit
of happiness,” the ultimate origins of his ideas lay in medieval juristic and
theological thought.
Bibliography
Ennio Cortese, La norma giuridica: Spunti teorici nel diritto comune classico (2
Vols. 1962) 1.1-141. Brian Tierney, “Natura id est Deus: A Case of Juristic
Pantheism?” Journal of the History of Ideas 24 (1963) 307-322, reprinted in
Church Law and Constitutional Thought in the Middle Ages (1979). Rudolf Weigand,
Die Naturrechtslehre der Legisten und Dekretisten von Irnerius bis Accursius und
von Gratian bis Johannes Teutonicus (1967). Daniel John O'Connor, Aquinas and
Natural Law (1968 [1967]). Francis Oakley, Natural law, Conciliarism and Consent
in the late Middle Ages: Studies in Ecclesiastical and Intellectual History
(1984). Anthony J. Lisska, Aquinas's Theory of Natural Law: An Analytic
Reconstruction (1996). Robert A. Greene, “Instinct of Nature: Natural Law, Synderesis, and the Moral Sense,” Journal of the History of Ideas 58 (1997)
173-198. Brian Tierney, The Idea of Natural Rights: Studies on Natural Rights,
Natural Law and Church Law 1150-1625 (1997).
Kenneth Pennington
The Catholic University of America
Washington, D.C.