Download Peking University – May 7th, 2013 Aquinas on Natural Law Riccardo

Peking University – May 7th, 2013
Aquinas on Natural Law
Riccardo Saccenti
1) General presentation of the topic: What is natural law and what about natural law in
Aquinas’s writings.
Natural law theories are a significant part of our philosophical panorama, particularly since the
1950s. Usually now days philosophers consider natural law as a concept opposed to positive law.
Natural law is considered as a natural order, a given system of principles, which have moral and
legal value; while positive law is the law established by human authorities, such as the State.
However, natural law and positive law are not considered in opposition by natural law theorists,
because, according to their point of view, positive law and natural law are two different levels of
one moral and legal order: natural law is the more general level of both a sheer social fact of power
and practice and a set of reasons for action with normative value.
The scholars that in the last decades have assumed the perspective of natural law theory give a
crucial importance to Thomas Aquinas’s doctrine on Natural law. This medieval thinker analysed
this issue in several parts of his considerable production. But it was particularly in question 94 of
the so called prima secundae (the first part of the second part) of his Summa Theologiae that he
offered a complete presentation of his opinion about natural law. In this text he gave a specific
answer to question such as: What is natural law? Are there precepts for the natural law? Is natural
the same for all human beings? Can natural law change?
We will consider the text of Aquinas and these questions in our analysis. To do so we will start by a
brief analysis of the main current interpretations of Aquinas’s natural law theory and later we will
suggest to assume, together with a philosophical perspective, a historical one. In this way,
considering the cultural framework in which Thomas worked and thought, we will better
understand the novelty of his perspective.
2) Current interpretations of Aquinas’s doctrine of natural law
During the XXth century, scholars offered different evaluations of Aquinas’s position about natural
law. These different interpretations are linked to the philosophical evolutions of the last century,
particularly in the understanding of the role of medieval cultural heritage. To facilitate, we can
distinguish four different interpretations.
According to the first perspective Thomas would have defined a system of immutable principle,
which constitute natural law, from which it could be possible to infer more specific moral rules.
A second interpretation suggests that Aquinas simply identify the key principle of natural law,
namely: “do what is good and avoid what is evil”. Human reason then implements this general
principle case by case, establishing what is good and what is evil according to the specific situation.
According to both the first and the second interpretation Aquinas’s doctrine has to be considered as
the final and perfect synthesis of a great and secular philosophical tradition, particularly of Christian
philosophy. This tradition started with the Fathers of the Church in the second century CE and
culminated in the ideas of Aquinas. This perspective is well exemplified in the writings of the
French scholar Etienne Gilson.
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A third approach is the one suggested by the French scholar Michel Villey, who examined
Aquinas’s doctrine in his studies on the history of Philosophy of Law. According to Villey Aquinas
offered a great synthesis about natural law, using all the sources he had at his disposal, but his
perspective is deeply linked to his age, i.e. to the mid thirteenth-century culture. What is important
of Aquinas’s account on natural law is the approach he adopted, namely the use of dialectic to
compare different positions and doctrines.
A fourth understanding is the one of the Australian legal philosopher John Finnis, who belongs to
the context of analytical philosophy. Finnis assumed Aquinas’s doctrine as the very basis for a
contemporary theory of natural law and devoted a specific study to the doctrine of Aquinas. The
Australian scholar suggests that Aquinas presents law as a plan for co-ordination through free
cooperation. According to this view, Aquinas’s natural law is a set of principles of practical reason
and morality, which can be understood, accepted and put into practice by every human being.
3) Historical approach to the topic
All the four perspectives about Aquinas’s theory stressed some aspects of the its content. Finnis’s
understanding, for instance, rightly stress the crucial role of human reason in Aquinas’s discourse.
But at the same time Villey conveniently suggests to consider the “antiquity” of Aquinas’s position
with respect to the contemporary philosophical debate. We can approach to Aquinas’s position is to
assume the best from these different perspectives and to consider briefly the historical and cultural
context of Aquinas’s time before focusing on the crucial passage of the Summa Theologiae about
natural law.
The topic of natural law became one of the major issues in the legal and philosophical debate of
Western European Culture since the very beginning of the XIIth century. According to the civil
lawyers natural law was just the law of nature, i.e. the law that regulates the life of all beings and
that human beings share with all the other animals. Civil lawyers assumed this idea in order to
specify that the law that has a prescriptive value for human beings is just the positive law, i.e. the
law established by political authority such as the emperor.
Both canon lawyers and theologians offered a completely different perspective. Canon lawyers
stressed the fact that natural law is not only the law of nature, i.e. of creation, but is more
importantly the moral and legal rule that God inscribed in human mind and which is the very basis
for every moral action and for every legal system. Gratian, in the very beginning of his fundamental
work, the Concordantia discordantium canonum (i.e. ‘the concordance of the discordant canons’),
distinguished human and divine laws, stressing the fact that divine law rests upon nature (natura
consistit) and is contained ‘in the Law and in the Gospel’, namely in the Bible. Peter Abelard had
already this idea some years before Gratian. In his famous ‘Dialogue between a Christian a Jews
and a Philosopher’ he stressed the fact that the very basis of ethics is natural law, namely a set of
moral precepts which are both evident to human mind by nature and are clearly exposed in the
Scripture. According to this perspective natural law is not only an instinct of nature, but something
which is established by the will of God, something which rests upon reason and that human mind
can understand.
On the basis of these different positions the thirteenth-century thinkers started to consider natural
law as a part of a more complex and articulate system of laws, with different degrees and levels.
According to authors like William of Auxerre, natural law is the very basis for human moral life,
but its importance is limited to human life in this world. The supernatural aim of human life would
need something else, namely faith and the consequent spirit of charity.
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The masters of the so-called ‘Dominican school’, such as Roland of Cremona, note that natural law
is the inner aim of each created being, so that there is a natural law for plants, which orients them to
develop according to their own nature, a natural law for animals, which inclines them to reproduce
their species in the better way, and finally a natural law for human beings, which is our inner
capacity to avoid evil that inclines us to act well. Albert the Great, who was the master of Aquinas,
developed this last position and stressed the fact that natural law is what is appropriate for human
nature as rational nature. Albert notes that for human beings natural law is a matter of reason and
the animal aspects of it, namely natural law as instinct of nature, concerns natural law just as
regulate by reason.
A different position was developed inside the other great school of thought of the time, namely the
so-called ‘Franciscan school’. The authors of this tradition stressed the fact that natural law
influences both the faculty of acting and the faculty of understanding, i.e. will and reason, the two
components of human freedom. Natural law is presented as a sort of habit, a disposition acquired by
human beings. According to this perspective natural law is the rule of human freedom and is
something which depends mainly by the will of God. It is a rule established by the Creator.
4) Aquinas’s position on natural law: analysis of Summa Theologiae Ia-IIae, q. 94
Thomas Aquinas studied the issue of natural law mainly in the second part of the first part of his
Summa Theologiae. Here e devoted an entire treaty to the topic of “Law”, within which he analysed
the nature of natural law. This writing is contemporary to his commentary on Aristotle’s
Nicomachea Ethics, where he found the opportunity to discuss natural law examining book V of
Aristotle’s work. We can consider more closely the content of Aquinas text.
Firstly Aquinas asks if natural law is a habit, like the Franciscan masters and other among its
contemporaries thought. In doing so he recalls his own statement about the existence of natural law.
As all the kinds of laws, also natural law is a matter of reason. Aquinas, in fact, defines natural law
as a participation of the eternal law in a rational creature, i.e. a human being. Each person can
participate in the eternal reason of God, “through which he has a natural inclination towards
deriving its proper act and end” (ST Ia-IIae, q. 91, a. 2).
Thus natural law is a principal of order and a product of reason, something that reason can
understand and establish. In this sense, Aquinas notes, natural law cannot be a habit, i.e. a
disposition acquired by human being, simply because it is established by human reason. Moreover,
natural law is not the cause of our action as humans: it is something that we do, a product of reason
which consists in practical judgments. Doing natural law our mind produce, in fact, a series of
precepts and rules, which can be assumed as habits. So in this sense natural law can be called a
habit, because its precepts are assumed by reason in the form of a habit.
Aquinas then focuses on the consistency of natural law: does it contain several precepts of only
one? To answer to this question Aquinas traces a parallel between practical and theoretical reason.
He notes, in fact, that intellect works in the same way both in practical and theoretical activities.
Then he observes that there are principles which are ‘self-evident’. There are two ways according to
which a proposition can be called self-evident: objectively, i.e. when its predicate is contained in
within the concept of the subject, or relatively to us as knowers. ‘Humans are rational’, for instance,
Aquinas notes, is self-evident, because to say ‘human’ is to say ‘rational’. However, if someone
doesn’t know what ‘human’ means, the proposition is not self-evident. This kind of propositions is
self-evident relatively to the knower; while another category of propositions is self-evident because
everyone can understand their contents. ‘Every whole is greater than its parts’, for instance, is such
a kind of proposition.
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Among the objectively self-evident propositions we have also the one which is at the very basis of
the understating of the concept of ‘being’, namely the principle: “To affirm and simultaneously to
deny is excluded’. It is in fact self-evident that the being is and the non-being is not. Thus being is
what is self-evident to theoretical reason. Because the intellect operates in the same way also on the
practical side, there must be something self-evident also according to the practical reason, and this
is good. Everyone, in fact, acts on account of an end, and this end includes in its concept the
intelligibility of good, because ‘Good is what each thing tends towards’. This principle, Aquinas
notes, can be formulated also as follow: ‘Good is to be done and pursued and evil is to be avoided’.
This last statement is the basic precept of natural law, on which rest all the other precepts and rules.
On this basis, in fact, there is in human beings an inclination to preserve its own being, an
inclination which is shared with all the living things. On the same principle rests also the inclination
to reproduction of the species and to take care of children, which human beings share with animals.
Finally the principle of natural law is the base for the inclination to those goods proper of human
nature as rational.
According to this idea, namely that there is a general high precept of natural law upon which all
other precepts and principles rest, Aquinas clarify that natural law is something immutable but just
according to the main principles. Only the general precept: ‘Good is to be done and pursued and
evil is to be avoid’, is immutable. All the applications of the principle to specific cases and
circumstances, as well as all the moral and legal rules derived from it, are the consequence of the
activity of practical reason. They are a practical judgment made through a comparison between a
specific situation of a kind of action and the general precept. Therefore these lower precepts are
mutable and can change according to the evaluation of practical reason.
5) Conclusions and final considerations
Aquinas’s account on natural law appears to be quite unique in the philosophical panorama of the
thirteenth-century Western European culture. Jurists consider natural law only as the foundation of
the legal and moral order, Aquinas stresses how the understanding of natural law involve an
understanding of human nature, particularly of the specific feature of human nature: rationality. At
the same time he assumes a clear philosophical perspective speaking about natural law. His
contemporaries, such the Franciscan authors and the large part of his Dominican brothers, though of
natural law as a fix and universal set of rules established by God and that human beings can
understand through reason to comply with in their moral life. Otherwise Aquinas suggests that
natural law, as every kind of law is a matter of human reason.
Considered from the human point of view, natural law is simply the human participation to the
eternal law, i.e. to the law established by the eternal rationality of God. Human rationality is in fact
capable to grasp the basic precept of natural law: ‘Good is to be done and pursued and evil is to be
avoided’. How to transcribe this general precept in the specific circumstances of human life
depends upon the action of practical reason and its judgments. This suggests that, according to
Aquinas, moral rules and precepts can change according to cultural and historical circumstances. If
there is a general precept, this operates as a guide for practical reason, which has the responsibility
to evaluate what is ‘good’ and what is ‘evil’ in every circumstance.
Riccardo Saccenti
[email protected]
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Basic bibliography
Thomas Aquinas, Summa Theologiae, Ia-IIae, qq. 90-107 (Treaty of Law)
O. Lottin, Le droit naturel chez saint Thomas et ses prédécesseurs, Ch. Beyaert éditeur, Bruges
1931;
H.V. Jaffa, Thomism and Aristotelianism. A Study of the Commentary by Thomas Aquinas on the
Nichomachean Ethics, The University of Chicago Press, Chicago 1952, [in particular pp. 167-188];
M. Villey, Leçons d’histoire de la philosophie du droit, Librairie Dalloz, Paris 1957 [in particular
pp. 185-193];
J. Finnis, Natural Law and Natural Rights, Oxford University Press, Oxford 1980 [reprinted in
2011];
R. McInerny, Ethica Thomistica. The Moral Philosophy of Thomas Aquinas, The Catholic
University of America Press, Washington D.C. 1982 [reprinted in 1997];
A.J. Lisska, Aquinas’s Theory of Natural Law. An Analytic Reconstruction, Clarendon Press,
Oxford 1996;
J. Finnis, Aquinas. Moral, Political, and Legal Theory, Oxford University Press, Oxford 1998;
Id, Aquinas’s Moral, Political, and Legal Philosophy, in Stanford encyclopedia of philosophy 2011,
http://plato.stanford.edu/entries/aquinas-moral-political/#Law;
M. Murphy, The Natural Law Tradition in Ethics, in Stanford encyclopedia of philosophy 2011,
http://plato.stanford.edu/entries/natural-law-ethics/
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