From IVR encyclopedie
The concept of natural law figures in an enormous amount of theories from the Stoics to the present, which makes it impossible to give a precise definition. To a large extent the meaning of the term depends on the social and political context as well as the theoretical framework in which the term is employed.
Having this in mind, it might nevertheless be useful to bring some order in the subject, by pointing to several characteristic assumptions that most natural law theories have in common. But before that, it is useful to distinguish a few assumptions that natural law doctrines typically do not share.
First: the concept of natural law as employed in legal or political theories should be distinguished from the kind of natural laws that figure in the sciences. Natural law theory does not set out to unravel a set of laws of nature that can describe and explain natural (physical, chemical or biological) phenomena. It is plausible that the scientific concept of natural laws is derived from an older view according to which natural phenomena are thought to `obey' the laws of a superior being or God. In the Stoic doctrine, for example, both human and inhuman behaviour was understood by reference to the decrees of a supreme Lawgiver. Gradually, however, the two concepts drifted apart, as will be pointed out in more detail below.
Second: in the context of legal and political theories, the concept of natural law is not used as a tool of explanation. Most natural law theorists do not set out to explain moral, legal or political arrangements by reference to (human) nature, but to justify and to criticise them. Nature is not an explanans, but a normative tool in order to distinguish good from bad law. Here again, the distinction has not always been that strict. Older doctrines of natural law use nature indiscriminately both as explanation and as a normative device. Gradually, however, also these two notions drifted apart.
If we confine the discussion of natural law theory to those theories in which natural law is meant as a normative tool for the justification and critique of existing positive law, three assumptions can be held to be commonly shared by all natural law thinkers. These are:
a) the assumption that there are universal and eternally valid criteria and principles on the basis of which positive law can be justified and/or criticised.
b) the assumption that these criteria and principles are grounded in nature, either physical nature, or more specifi cally, human nature;
c) the assumption that human beings can discover those principles by the use of reason.
A higher law
Assumption a) is the most general one and not necessarily restricted to natural law theories. Many religious believers cherish assumption a), believing that these criteria are furnished by God. But this belief alone doesn't turn them into natural law thinkers. In the Antigone of Sophocles, to mention an example that is often cited in treatises on natural law, a higher law is invoked by Antigone to justify her rebel lion against the decree of king Creon, but to call her an early proponent of natural law theory would amount to an unnecessary inflation of the term `natural law', since the source of her higher law is supernatural rather than natural. Assumption a) is therefore indispensable for anyone committed to natural law thinking, but it is not a sufficient condition.
Assumption b) presupposes a fundamental distinction between nature and a man-made world. Although the concepts of nature can be different, virtually all natural law thinkers have such an opposition in mind.
By itself, a sharp distinction between nature and culture does not yet make a natural law theory. The Sophists, for example, equally presupposed a dichotomy between nature and a man-made world. But they meant by `nature' the struggle for life in which all species are involved and they conceived of human conventions and laws as tools of survival. The uncertainty and irrationality of their concept of nature, coupled with the useful qualities of their view of the man-made world could not give rise to the idea, essential to natural law, that nature provides the eternal criteria for judging human conventions.
It is therefore only where nature, whatever its exact meaning is, is regarded as the solid foundation of a changing world, that it can be thought to provide a reliable guide or model for human arrangements. The central idea in virtually all versions of natural law theory is that the man-made world is fleeting and changing according to time and place, whereas nature is universal, eternal and unchangeable by men. Only on the basis of that contrast can assumptions a) and b) be combined in a meaningful way.
But there are enormous variations to be found on this theme, which are partly brought about by the different understandings of what should count as nature. In the Aristotelian teleological framework, nature is understood as the entire dynamic order, striving perpetually to its self-realization. For Aquinas (1224-1274), who incorporated the Aristotelian notions in a Christian framework, every creature seeks to realize its own end (implanted by God). Their inclinations can be seen as a sign of their proper function, which they should seek to fulfil. Description of natural phenomena can therefore easily lead to the formulation of normative principles. These natural laws are thought to be applicable to the entire created universe.
In the 17th century, the term `nature', when employed in natural law theory, is confined to human nature alone. Since the description of human nature is no longer embedded in a teleological framework, in which creatures are seen as exercising their true or proper function, it is now ambiguous whether these features are meant as description of what human nature is like, or whether they are ideals to which men should strive.
This ambiguity was accompanied by a persistent dilemma: a sober, empirical description of human nature and its shortcomings cannot be the source of eternal criteria, whereas an idealised version of human nature seems to render the notion of natural law superfluous. If human beings by themselves already possess the virtues required, why would we need a natural law to tell us what we should do?
Assumption c) presupposes that nature and the criteria that can be deduced from nature, are accessible to human reason. Like the concept of nature, the concept of reason is different in the various versions of natural law theory. The deduction of natural law can be thought of as consisting in an immediate perception of self-evident truths (Finnis), or as a laborious process of reasoning (Suárez). It can be thought to require experience and practical wisdom (Aquinas), or it can be identified with mathematical reasoning (Locke). In all these cases, however, natural law thinkers claim that the ultimate criteria for distinguishing good and bad law can in principle be known and taught.
The kind of reason required is to a large extent dependent on the kind of `laws' that were perceived to be the object of that knowledge. Aquinas conceives of natural law as a set of some global principles. These principles can be known and grasped with great certainty, but it is to (fallible) human reason to work out the consequences of these principle for the practical questions of everyday life, and in that train of argument certainty is lost. It can only be compensated by prudence, wisdom and experience.
The 16th century thinker Francisco Suárez (1548-1617), on the other hand, claims that the most important part of natural law consists of the more concrete rules that are derived from the first principles. For Suárez, a strict process of deduction can guarantee the degree of certainty required.
In 17th century natural law theory, admiration for the achievements of mathematics led to the expectation that `the geometrical method' can also lead to certainty when applied to moral affairs. Human nature should serve as an axiom from which indubitable truths could be deduced. Although the geometrical method is advocated by virtually every serious natural law thinker of the period (Hobbes, Locke, Grotius, Leibniz, Wolf), examples of a successful application of the method are rare and where they are produced (e.g. Locke's famous principle `where there is no property, there is no injustice') they come close to tautologies.
Finally, the 20th century school of natural lawyers around John Finnis and Germain Grisez, maintain that the first basic principles of natural law (conceived as basic goods) can be known in a self-evident manner, which requires no further proof.
Natural reason and rational nature
Both assumptions b) and c) are responsible for the term `natural law'. `Natural' both refers to the fact that the law is grounded in nature, and that the law can be known and discovered by the aid of natural reason (lumen naturale) alone, in opposition to supernatural revelation. For some writers, the link between assumptions b) and c) is very tight. For Cicero, `true law is right reason in agreement with nature'. Locke, who in his earlier essays had conceived of reason as an instrument to know natural law, in his later work identified reason as the law of nature. This identification is not surprising. It forms the basis of the whole edifice of natural law to think that since man's nature is rational, we human beings can have access to rational nature and derive from that the criteria we need.
Taken together, the picture of natural law theory that emerges can be characterised as an attempt to provide arguments for the belief that order and certainty in moral affairs can be obtained. This order is derived from the belief that there is a universal order inherent in (human) nature and that that order can be discovered and known in a controlled manner. One might say that in times where men experience the man-made world as capricious, arbitrary, and unreliable (e.g. 16th century religious wars), the longing for nature as a solid foundation for eternal criteria is most acutely felt.
The problem of obligation
Assumptions b) and c) together, although they include a wide variety of (conflicting) notions and ideas, have no room for the notion of an impenetrable law that is based on the divine will. Voluntarist notions that the ultimate criteria and standards are grounded in the will of God and can be changed overnight at His mercy, are constantly criticised as being too arbitrary.
The fact that the element of will is systematically left out, causes two problems. First, the theological problem that the supremacy of rational nature over God's will seemed to imply the blasphemous notion that God himself was bound to obey the dictates of rational nature and was apparently not to be regarded as free and omnipotent. A large extent of 16th century natural law theory is devoted to this problem.
More troublesome, however, is the problem of obligation. For natural law theory is essentially alegalistic theory: the moral criteria that can decide whether positive law can be justified, are themselves conceived as laws that can be made explicit by formulation and promulgation. But how can we understand these laws to have obligatory force if we do not presuppose a primary sovereign will as their source? Nature alone can indicate moral good or evil, it can at the most suggest courses of action that are in conformity with rational nature, but it cannot oblige us to act in conform ity with natural law.
This problem was not immediately felt in a teleological framework, where the order of things is dynamic. Trees do not have to be compelled to grow, nor do human beings have to be obliged to act socially. In a teleological view it is sufficient to discover one's true inclinations and not to act against them. However, as soon as the rational order of the universe is seen as static, nature itself is not able to move creatures to their ends. Reason may declare which acts are in conformity with rational nature, or which acts disagree with nature, but nature itself is felt to be inert, as something that cannot give rise to obligations.
Some solutions, reintroducing God's will as an element that should be added to the mix of nature and reason, were suggested to fill this normative gap, but threatened to make an end to the claim of natural law theory to furnish criteria that are completely transparent to the human mind.
The secularisation of natural law
From the start, (most varieties of) natural law theory had the tendency to bypass divine or eternal law as the source for moral principles. It is true that Aquinas stressed that natural reason was only a limited and imperfect way of knowing God's plans and inferior to the knowledge transmitted by the Scripture, but the very idea that it is possible for `unaided reason' to discover eternal moral truths had high secularizing potential.
The shift from rational nature as a whole towards human nature as the source for moral criteria heightened this potential. Writers like Locke, Grotius and Pufendorf all seemed to believe that they could solve the theological problem of God's limited freedom, as explained above, by stressing that God had been free while creating man, but that once mankind had been created as it is now, it could no longer be changed or annulled, not even by God. If God wanted to change the law of nature he had first to change human nature. In Locke's words: natural law was `coeval with the human race'.
It was an ingenuous solution, for it seemed both to do justice to God's freedom and to safeguard the idea that natural law could be known and taught, since its basis is human nature. But practically speaking, it removed God from moral discourse. Once God had created human beings, His moral role had come to an end. It is to man and to man alone to decide which acts are or are not in harmony with his intrinsic nature.
The naturalistic fallacy
The problem that rational nature by itself can only indicate moral rectitude but does not give rise to obligatorynorms, was intensified by the shift from rational nature to human nature. In order to discover eternal laws, man was left to himself only to consult his own nature. This nature was no longer conceived as dynamic, but as static, something that God himself didn't change anymore. Moreover, protestant theology stressed that human nature was weak, depraved, even wicked. How can human nature then serve as a basis for eternally and universally valid moral criteria?
The door was open to the kind of criticism that David Hume has become famous for and according to which natural law theories all suffer from the same mistake, the so-called `naturalistic fallacy'. This fallacy consists in the belief that norms can be deduced from facts; that `ought-statements' are derived from `is-statements' without the intervention of a higher norm or goal which connects factual descriptions to normative prescriptions.
One might doubt whether natural law theory ever recovered from the attack. It is certain, however, that the group around Finnis, who try to rehabilitate natural law theory, are so anxious to avoid the naturalistic fallacy that they are eager to deny the role played by nature altogether, asserting that the principles they look for are really no natural law principles, but principles that guide practical reasoning.
Contemporary natural law
It is sometimes claimed that the post-war period after 1945 witnessed a revival of natural law theory. A closer look at what counts as such a revival, however, raises doubts as to the accuracy of that claim. Most statements concerning such a revival allude to the post-war international tribunals and resulting body of international law. In so far as the principles of international law were not codified or otherwise turned into positive law, the application of concepts like `crimes against humanity' is sometimes thought to be a sign of revived natural law theory, but is in fact no more than a version of assumption a): the unspecified assumption that there is `a' higher law.
The second source for the belief that natural law theory is revived is to be found in the claim of some critics of legal positivism, that they adopt a version of natural law. An example is furnished by Lon L. Fuller, who asserts that his theory should be regarded as a kind of `procedural natural law'. Most of these claims, however, only refer to the relationship between law and morals in general. `Natural law' here means usually no more than the opinion that there is no separation between law and morals, that morality always form part and parcel of law, or that there are intrinsic moral values to be attached to law in order to count as true law. Since these theories have no room for assumptions b) and c), it is more appropriate to label these theories simply as `anti-positivist'.
The third way in which natural law can be said to be revived is by pointing to the work of Finnis and Grisez. Their set of ideas indeed come closer to the heritage of Aquinas than any other contemporary theory. At least they try to make sense not only of assumption a) but also of as sumption c). As pointed out above, the problem arises as to assumption b). The role of nature is limited to a minimum in their accounts.
Finally, one might say, not without reason, that natural law is revived in the form of natural rights, or more properly speaking in human rights. And indeed, it is defensible to regard rights theories as worthy successors of natural law theories. Already in Grotius (1583-1645) it is possible to see a transition from natural law doctrine to a doctrine of subjective natural rights, be it that the subjects Grotius had in mind were the national states and not individuals. When the concept was later attached to human beings as individual moral persons (Kant) a new doctrine was born, with its own particular problems which fall outside the scope of discussion of natural law theory proper.