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The concept of natural law has taken several forms. The idea began with the ancient Greeks'
conception of a universe governed in every particular by an eternal, immutable law and in their
distinction between what is just by nature and just by convention. Stoicism provided the most
complete classical formulation of natural law. The Stoics argued that the universe is governed
by reason, or rational principle; they further argued that all humans have reason within them
and can therefore know and obey its law. Because human beings have the faculty of choice (a
free will), they will not necessarily obey the law; if they act in accordance with reason, however,
they will be "following nature."
Christian philosophers readily adapted Stoic natural law theory, identifying natural law with the
law of God. For Thomas Aquinas, natural law is that part of the eternal law of God ("the reason
of divine wisdom") which is knowable by human beings by means of their powers of reason.
Human, or positive, law is the application of natural law to particular social circumstances. Like
the Stoics, Aquinas believed that a positive law that violates natural law is not true law.
With the secularization of society resulting from the Renaissance and Reformation, natural law
theory found a new basis in human reason. The 17th-century Dutch jurist Hugo Grotius
believed that humans by nature are not only reasonable but social. Thus the rules that are
"natural" to them -- those dictated by reason alone -- are those which enable them to live in
harmony with one another. From this argument, by the way, Grotius developed the first
comprehensive theory of international law.
Natural law theory eventually gave rise to a concept of "natural rights." John Locke argued that
human beings in the state of nature are free and equal, yet insecure in their freedom. When
they enter society they surrender only such rights as are necessary for their security and for the
common good. Each individual retains fundamental prerogatives drawn from natural law
relating to the integrity of person and property (natural rights). This natural rights theory
provided a philosophical basis for both the American and French revolutions. Thomas Jefferson
used the natural law theory to justify his trinity of "inalienable rights" which were stated in the
United States Declaration of Independence.
During the 19th century natural law theory lost influence as utilitarianism and Bentham’s,
positivism, materialism, and the historical school of jurisprudence became dominant. In the
20th century, however, natural law theory has received new attention, partly in reaction to the
rise of totalitarianism and an increased interest in human rights throughout the world. With this
contemporary interest in mind, let's now turn to our attention to the natural law theory as
understood by the tradition of Classical Realism.
In its simplest definition, natural law is that "unwritten law" that is more or less the same for
everyone everywhere. To be more exact, natural law is the concept of a body of moral
principles that is common to all humankind and, as generally posited, is recognizable by human
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reason alone. Natural law is therefore distinguished from -- and provides a standard for --
positive law, the formal legal enactments of a particular society.
Since law must always be some dictate of reason, natural law also will be some dictate of
reason. In fact, it is the law discovered by human reason. Our normal and natural grasp of the
natural law is affected by reason, that is, by the thinking mind, and in this service reason is
sometimes called "conscience." We, in all our human acts, inevitably see them in their relation
to the natural law, and we mentally pronounce upon their agreement or disagreement with the
natural law. Such a pronouncement may be called a "judgment of conscience." The "norm" of
morality is the natural law as applied by conscience. Lastly, we can say that the natural law is
the disposition of things as known by our human reason and to which we must conform
ourselves if we are to realize our proper end or "good" as human beings.
To sum it up, then, we can say that the natural law:
is not made by human beings;
is based on the structure of reality itself;
is the same for all human beings and at all times;
is an unchanging rule or pattern which is there for human beings to discover;
is a means by which human beings can rationally guide themselves to their good.
It is interesting to note that virtually everyone seems to have some knowledge of natural law
even before such knowledge is codified and formalized. Even young children make an appeal to
"fair play," demand that things be "fair and square," and older children and adults often apply
the "golden rule." When doing so, they are spontaneously invoking the natural law. This is why
many proponents of the natural law theory say it is the law which is "written upon the hearts of
1. Kinds of Natural Law Theory
The first is a theory of morality. First, moral propositions have what is sometimes called
objective standing in the sense that such propositions are the bearers of objective truth-
value; that is, moral propositions can be objectively true or false. Though moral objectivism
is sometimes equated with moral realism, the relationship between the two theories is
controversial. Geoffrey Sayre-McCord, for example, views moral objectivism as one
species of moral realism, but not the only form; on Sayre-McCord’s view, moral
subjectivism and moral intersubjectivism are also forms of moral realism. Strictly speaking,
then, natural law moral theory is committed only to the objectivity of moral norms.
The second thesis constituting the core of natural law moral theory is the claim that standards
of morality are in some sense derived from, or entailed by, the nature of the world and the
nature of human beings. St. Thomas Aquinas, for example, identifies the rational nature of
human beings as that which defines moral law: “the rule and measure of human acts is the
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reason, which is the first principle of human acts”. On this common view, since human beings
are by nature rational beings, it is morally appropriate that they should behave in a way that
conforms to their rational nature. Thus, Aquinas derives the moral law from the nature of
human beings (thus, “natural law”).
But there is another kind of natural law theory having to do with the relationship of morality to
law. According to natural law theory of law, there is no clean division between the notion of law
and the notion of morality. Though there are different versions of natural law theory, all
subscribe to the thesis that there are at least some laws that depend for their “authority” not
on some pre-existing human convention, but on the logical relationship in which they stand to
moral standards. Otherwise put, some norms are authoritative in virtue of their moral content,
even when there is no convention that makes moral merit a criterion of legal validity. The idea
that the concepts of law and morality intersect in some way is called the Overlap Thesis.
As an empirical matter, many natural law moral theorists are also natural law legal theorists,
but the two theories, strictly speaking, are logically independent. One can deny natural law
theory of law but hold a natural law theory of morality. John Austin, the most influential of the
early legal positivists, for example, denied the Overlap Thesis but held something that
resembles a natural law ethical theory.
Indeed, Austin explicitly endorsed the view that it is not necessarily true that the legal validity
of a norm depends on whether its content conforms to morality. But while Austin thus denied
the Overlap Thesis, he accepted an objectivist moral theory; indeed, Austin inherited his
utilitarianism almost wholesale from J.S. Mill and Jeremy Bentham. Here it is worth noting that
utilitarians sometimes seem to suggest that they derive their utilitarianism from certain facts
about human nature; as Bentham once wrote, “nature has placed mankind under the
governance of two sovereign masters, pain and pleasure. It is for them alone to point out what
we ought to do, as well as to determine what we shall do. On the one hand the standard of
right and wrong, on the other the chain of causes and effects, are fastened to their throne”
(Bentham 1948, 1). Thus, a commitment to natural law theory of morality is consistent with the
denial of natural law theory of law.
Conversely, one could, though this would be unusual, accept a natural law theory of law
without holding a natural law theory of morality. One could, for example, hold that the
conceptual point of law is, in part, to reproduce the demands of morality, but also hold a form
of ethical subjectivism (or relativism). On this peculiar view, the conceptual point of law would
be to enforce those standards that are morally valid in virtue of cultural consensus. For this
reason, natural law theory of law is logically independent of natural law theory of morality. The
remainder of this essay will be exclusively concerned with natural law theories of law.
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2. Conceptual Naturalism
a. The Project of Conceptual Jurisprudence
The principal objective of conceptual (or analytic) jurisprudence has traditionally been to
provide an account of what distinguishes law as a system of norms from other systems of
norms, such as ethical norms. As John Austin describes, conceptual jurisprudence seeks “the
essence or nature which is common to all laws that are properly so called”. Accordingly, the
task of conceptual jurisprudence is to provide a set of necessary and sufficient conditions for
the existence of law that distinguishes law from non-law in every possible world.
While this task is usually interpreted as an attempt to analyze the concepts of law and legal
system, there is some confusion as to both the value and character of conceptual analysis in
philosophy of law. As Brian Leiter points out, philosophy of law is one of the few philosophical
disciplines that take conceptual analysis as its principal concern; most other areas in philosophy
have taken a naturalistic turn, incorporating the tools and methods of the sciences. To clarify
the role of conceptual analysis in law, Brian Bix distinguishes a number of different purposes
that can be served by conceptual claims: (1) to track linguistic usage; (2) to stipulate meanings;
(3) to explain what is important or essential about a class of objects; and (4) to establish an
evaluative test for the concept-word. Bix takes conceptual analysis in law to be primarily
concerned with (3) and (4).
In any event, conceptual analysis of law remains an important, if controversial, project in
contemporary legal theory. Conceptual theories of law have traditionally been characterized in
terms of their posture towards the Overlap Thesis. Thus, conceptual theories of law have
traditionally been divided into two main categories: those like natural law legal theory that
affirm there is a conceptual relation between law and morality and those like legal positivism
that deny such a relation.
b. Classical Natural Law Theory
All forms of natural law theory subscribe to the Overlap Thesis, which asserts that there is some
kind of non-conventional relation between law and morality. According to this view, then, the
notion of law cannot be fully articulated without some reference to moral notions. Though the
Overlap Thesis may seem unambiguous, there are a number of different ways in which it can be
The strongest construction of the Overlap Thesis forms the foundation for the classical
naturalism of Aquinas and Blackstone. Aquinas distinguishes four kinds of law: (1) eternal law;
(2) natural law; (3) human law; and (4) divine law. Eternal law is comprised of those laws that
govern the nature of an eternal universe; as Susan Dimock (1999, 22) puts it, one can “think of
eternal law as comprising those entire scientific (physical, chemical, biological, psychological,
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etc.) ‘Laws’ by which the universe is ordered.” Divine law is concerned with those standards
that must be satisfied by a human being to achieve eternal salvation. One cannot discover
divine law by natural reason alone; the precepts of divine law are disclosed only through divine
The natural law is comprised of those precepts of the eternal law that govern the behavior of
beings possessing reason and free will. The first precept of the natural law, according to
Aquinas, is the somewhat vacuous imperative to do well and avoid evil. Here it is worth noting
that Aquinas holds a natural law theory of morality: what is good and evil, according to Aquinas,
is derived from the rational nature of human beings. Good and evil are thus both objective and
But Aquinas is also a natural law legal theorist. On his view, a human law (that is, that which is
promulgated by human beings) is valid only insofar as its content conforms to the content of
the natural law; as Aquinas puts the point: “every human law has just so much of the nature of
law as is derived from the law of nature. But if in any point it deflects from the law of nature, it
is no longer a law but a perversion of law”. To paraphrase Augustine’s famous remark, an unjust
law is really no law at all.
The idea that a norm that does not conform to the natural law cannot be legally valid is the
defining thesis of conceptual naturalism. Blackstone articulates the two claims that constitute
the theoretical core of conceptual naturalism: 1) there can be no legally valid standards that
conflict with the natural law; and 2) all valid laws derive what force and authority they have
from the natural law.
It should be noted that classical naturalism is consistent with allowing a substantial role to
human beings in the manufacture of law. While the classical naturalist seems committed to the
claim that the law necessarily incorporates all moral principles, this claim does not imply that
the law is exhausted by the set of moral principles. There will still be coordination problems
(e.g., which side of the road to drive on) that can be resolved in any number of ways consistent
with the set of moral principles. Thus, the classical naturalist does not deny that human beings
have considerable discretion in creating natural law. Rather she claims only that such discretion
is necessarily limited by moral norms: legal norms that are promulgated by human beings are
valid only if they are consistent with morality.
Critics of conceptual naturalism have raised a number of objections to this view. First, it has
often been pointed out that, contra Augustine, unjust laws are all-too- frequently enforced
against persons. As Austin petulantly put the point:
Now, to say that human laws which conflict with the Divine law are not binding, that is to say,
are not laws, is to talk stark nonsense. The most pernicious laws, and therefore those which are
most opposed to the will of God, have been and are continually enforced as laws by judicial
tribunals. Suppose an act innocuous, or positively beneficial, be prohibited by the sovereign
under the penalty of death; if I commit this act, I shall be tried and condemned, and if I object
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to the sentence, that it is contrary to the law of God, who has commanded that human
lawgivers shall not prohibit acts which have no evil consequences, the Court of Justice will
demonstrate the inconclusiveness of my reasoning by hanging me up, in pursuance of the law
of which I have impugned the validity (Austin 1995, 158).
Of course, as Brian Bix points out, the argument does little work for Austin because it is always
possible for a court to enforce a law against a person that does not satisfy Austin’s own theory
of legal validity.
Another frequently expressed worry is that conceptual naturalism undermines the possibility of
moral criticism of the law; inasmuch as conformity with natural law is a necessary condition for
legal validity, all valid law is, by definition, morally just. Thus, on this line of reasoning, the legal
validity of a norm necessarily entails its moral justice. As Jules Coleman and Jeffrey Murphy
(1990, 18) put the point:
The important things [conceptual naturalism] supposedly allows us to do (e.g., morally evaluate
the law and determine our moral obligations with respect to the law) are actually rendered
more difficult by its collapse of the distinction between morality and law. If we really want to
think about the law from the moral point of view, it may obscure the task if we see law and
morality as essentially linked in some way. Moral criticism and reform of law may be aided by
an initial moral skepticism about the law.
There are a couple of problems with this line of objection. First, conceptual naturalism does not
foreclose criticism of those norms that are being enforced by a society as law. Insofar as it can
plausibly be claimed that the content of a norm being enforced by society as law does not
conform to the natural law, this is a legitimate ground of moral criticism: given that the norm
being enforced by law is unjust, it follows, according to conceptual naturalism, that it is not
legally valid. Thus, the state commits wrong by enforcing that norm against private citizens.
Second, and more importantly, this line of objection seeks to criticize a conceptual theory of
law by pointing to its practical implications ñ a strategy that seems to commit a category
mistake. Conceptual jurisprudence assumes the existence of a core of social practices
(constituting law) that requires a conceptual explanation. The project motivating conceptual
jurisprudence, then, is to articulate the concept of law in a way that accounts for these pre-
existing social practices. A conceptual theory of law can legitimately be criticized for its failure
to adequately account for the pre-existing data, as it were; but it cannot legitimately be
criticized for either its normative quality or its practical implications.
A more interesting line of argument has recently been taken up by Brian Bix. Following John
Finnis, Bix rejects the interpretation of Aquinas and Blackstone as conceptual naturalists,
arguing instead that the claim that an unjust law is not a law should not be taken literally:
A more reasonable interpretation of statements like “an unjust law is no law at all” is that
unjust laws are not laws “in the fullest sense.” As we might say of some professional, who had
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the necessary degrees and credentials, but seemed nonetheless to lack the necessary ability or
judgment: “she’s no lawyer” or “he’s no doctor.” This only indicates that we do not think that
the title in this case carries with it all the implications it usually does. Similarly, to say that an
unjust law is “not really law” may only be to point out that it does not carry the same moral
force or offer the same reasons for action as laws consistent with “higher law” (Bix 1996, 226).
Thus, Bix construes Aquinas and Blackstone as having views more similar to the neo- naturalism
of John Finnis discussed below in Section III. Nevertheless, while a plausible case can be made
in favor of Bix’s view, the long history of construing Aquinas and Blackstone as conceptual
naturalists, along with its pedagogical value in developing other theories of law, ensures that
this practice is likely, for better or worse, to continue indefinitely.
Critical Appraisal of Natural Law Theory
The concept of natural law has been used to support different ideologies from time to time. It
has been used not only to support absolutism, individualism but also to overthrow government.
The natural law philosophy has contributed a lot in the development of law and legal system.
The natural law principles of justice, morality and conscience have been embodied in various
legal systems. Man-made positive laws are arbitrary ant contingent whereas natural being
regulated by laws of nature is inevitable and obligatory. Natural law emanating from ‘human
reasoning’ which is known for its uniformity and general acceptance is not variable. Natural law
helped in denouncing the divine authority of the Church. It helped in generating a favorable
climate for reformation, renaissance and provided a sound foundation for fundamental human
Natural law also played an important part in the development of modern law. Legal history
testifies that it was natural law which directly or indirectly provided a model for the first man-
made law. Appreciating the contribution of natural law Roscoe Pound said, “The uncertainty of
the higher law is preferable to the arbitrariness and insolence of naked force”.
Despite the merits of natural law philosophy, it has been criticized for its weakness on the
1. ‘Ought to be’ may not always necessarily conform to the needs of the society. For
instance. It is natural for men to beget children, as it is for trees to bear fruit. But many
would like to take the help of family planning measures in order to restrict the growth of
population but no one would like to restrict the growth of fruit on trees. Therefore,
giving birth to children may be a natural phenomenon but it may not always be
considered as obligatory moral duty of men to conform to this conduct.
2. The rules of morality embodied in natural law are not amenable to changes but the legal
rules do need a change with the changing needs of society.
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3. The concept of morality is a varying content changing from place to place; hence, it
would be futile to think over the universal applicability of law. It depends on the society.
One society may adhere to monogamy while the other one may permit plurality of
4. Disputes relating to laws of nature and morality cannot be subjected to judicial scrutiny
as the verdict may always be questioned since it is based on subjective discretion of the
Despite the above shortcomings, it cannot be denied that natural law has played a
crucial role in shaping the law. Its significance lies in the fact that an unjust law may not
last long and it is bound to lose public support in the absence of obedience by the
Natural Law Ideas in English Law
In some braches of modern English law, principles of natural justice are openly invoked
to test the validity of legal acts but that does not apply to test the validity of any Act of
parliament as Parliament is supreme in England. A custom is not permitted by courts if it
is not reasonable. By means of an order of prohibition or certiorari, the high court in
England can control administrative acts and quasi-judicial decisions of administrative
bodies which are contrary to the rules of natural justice.
Natural law ideas have exercised the most profound and enduring influence upon
English law as guiding principles in law making. The attempt of Lord Mansfield to
introduce the doctrine of unjust enrichment in English law was an applications of the
principles of natural justice.
The concept of quasi-contract in English law is based on natural law principles. The
principles of “justice, equality and good conscience” are based on natural law ideas.
While welcoming the American Bar Association in London in 1957, Lord Kilmaur,
referred to “the doctrine which we share with a wider community even that of the
common law but which has for various reasons become a little dusty and old-fashioned
in recent years and which I myself would like to see refurbished and restored to the
position which it once used to occupy. I refer to the doctrine of the law of nature, one of
the nobles conceptions in the history of jurisprudence.”
Natural Law and the Supreme Court of India
In recent years, the ideas of natural justice have become more and more important and
have been relied upon by the Supreme Court of India and High Courts in their decisions.
In A.K.Kraipak v. Union of India, the Supreme Court observed that the aim of the rules of
natural justice is to secure justice or to put it negatively, to prevent miscarriage of
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justice. These rules can operate only in areas not covered by any law validly made. They
do not supplant the law of the land but supplement it.
The concept of natural justice has undergone a great deal of change in recent years. In
the past it was thought that it included just two rules, namely:
1. No one shall be a judge in his own cause(nemo debet esse judex propria causa).
2. No decision shall be given against a party without affording him a reasonable
hearing(audi alteram partem).
Very soon thereafter, a third rule was added which provides that quasi-judicial enquiries
must be held in good faith, without bias and not arbitrarily or unreasonably.
In Maneka Gandhi v. Union of India, the Supreme Court observed that natural
justice is a great humanising principle intended to invest law with fairness and to secure justice.
Over the years, it has grown into a widely pervasive rule affecting large areas of administrative
action. The soul of natural justice is “fairplay in action” and it has received widest recognition
throughout the democratic world. The Supreme Court held that even the procedure laid down
by law must be right, just and fair. It is liable to be set aside on the ground that it is not
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1. Jurisprudence and Legal Theory by V.D.Mahajan.
2. The Province of Jurisprudence Determined.
3. Jurisprudence: The Philosophy & Method of the Law by Edgar Bordenheimer