See our websites!

"It is through conscience that human beings see and recognize the demands of the divine law. They are bound to follow their conscience faithfully in everything they do."
Religious Liberty, no 2.

The Traditional Concept of Natural Law: An Interpretation

by Dr Columba Ryan, OP
In Illud Evans (ed.), Light on Natural Law, Burns and Oates, London 1965, p. 13 - 37.

Fr Columba Ryan OPFr Columba Ryan OP completed his Doctorate of Philosophy at Oxford University at the age of 30 (in 1946). He enjoyed philosophical controversy and debate. While teaching philosophy at the Dominican House of Studies at Hawkesyard in 1954, he set up a Philosophical Enquiry Group, an annual meeting for Catholic philosophers held at Spode House.

This chapter on Thomas Aquinas's interpretation of Natural Law is a master piece.

I have tried to make his text more accessible to readers who are not familiar with Thomist philosphy. For that purpose I have added headings and captions before paragraphs, highlighting some words within paragraphs and comments on the side. All those are mine and not Father Ryan's.

John Wijngaards

Part One. Historical Introduction

In a short essay on the traditional concept of natural law it is hardly possible to go into the complicated story of its historical development. This history has often been written,(note 1) and it contains chapters about which there is little agreement among scholars. But without entering into these difficult questions, it may be useful to remind the reader of some of the strands that went to the making of the idea before it was given a certain coherence and consistency by St Thomas Aquinas and so inherited as a central concept in Catholic thought. For it is when we see something of its complexity, not to say its inherent tensions and conflicts, that we may appreciate that the traditional synthesis may still stand in need of elaboration or even qualification. The development of a complex idea is seldom absolutely finalized.

1.1 Greek writers on Natural Law

"The origin of the idea of natural law may be ascribed to an old and indefeasible movement of the human mind (we may trace it already in the Antigone of Sophocles) which impels it towards the notion of an eternal and immutable justice; a justice which human authority expresses, or ought to express - but does not make."(note 2) Sir Ernest Barker had in mind, of course, the often quoted lines of SOPHOCLES, where Antigone defends herself before Creon for burying Polynices in defiance of a positive edict:

"That order did not come from God.
Justice that dwells with the gods below, knows no such law.
I did not think your edicts strong enough To over-rule the unwritten,
unalterable laws of God and heaven, you being only a man.
They are not of yesterday or today, but everlasting.
Though where they come from, none of us can tell." (note 3)


Such a passage may seem to us a fairly clear appeal from the tyranny of man-made positive law to a higher law, eternal and unchallengeable, by which positive law may be judged.

And one might buttress such an interpretation by fragments from some of the pre-Socratic philosophers. XENOPHANES speaks of "things that are shameful and a reproach among people: theft, adultery, and mutual deception,"(note 4) and HERACLITUS of a law which, however much disregarded, is nevertheless binding and universal: "One must follow that which is common to all. But although the law is universal the majority live as if they had understanding peculiar to themselves."(note 5) For Heraclitus this is a matter of reason:

"If we speak with intelligence, we must base our strength on that which is common to all" and "the thinking faculty is common to all",(note 6) but for others it is perhaps seen to be rather a matter of "nature".

PHILOLAUS of Tarentum has left us the tantalizingly brief remark, "By nature, not by convention" (note 7) a contrast that may be at work in the Sophist Antiphon when he writes:

"The edicts of the laws are imposed artificially, but those of nature are compulsory. . . . If a man who transgresses the legal code evades those who have agreed to these edicts, he avoids both disgrace and penalty.. . . But if a man violates any of the laws which are implanted in nature, even if he evades all people’s detection, the ill is no less, and even if all see, it is no greater. For he is not hurt on account of an opinion, but because of truth."(note 8)

It is easy to interpret such passages as if "nature" and "truth" had some higher values than "convention" and "opinion"; but to do so may in fact be to read back our own ideas into these early authors. It is by no means clear that "nature" and "truth" do not rather represent what we should think of nowadays as a kind of blind, compelling instinct in contrast with the cooler calculations of human reason.

Perhaps the natural law to which Antigone appeals is not so much something ethically superior as naturally ineluctable - the instinct of nature which excuses and explains her action without making it morally defensible.

Such a concept, at any rate, of law, if law it may be called, is to be found in Democritus:

"For human beings it is one of the necessities of life to have children, arising from nature and primeval law. This is obvious in other animals too; they all have offspring by nature, and not for the sake of profit."(note 9)


1.2 Ancient Roman writers on Natural Law

So we may detect already two possible strands in the concept of natural law: the idea that it represents some higher ideal of justice to which appeal may be made, and the idea that it is a compulsively blind instinct of nature. The two ideas set up a tension and conflict within the notion of natural law that may be traced much later in its development, and that may be found still confusing discussions of the subject today.

When CICERO (whose writings were so influential in the development of the medieval concept) wrote of "true law which is right reason in agreement with nature, of universal application, unchanging and everlasting", he was seeing it as an ideal of justice; for he continued:

"It is a sin to try to alter this law, nor is it allowable to repeal any part of it, and it is impossible to abolish it entirely.. . . There will not be a different law at Rome and at Athens, a different law now and in the future, but one eternal and unchangeable law for all nations and for all times."(note 10)

But another approach to the natural law is to be found in a famous definition, well known and influential in the Middle Ages, given by ULPIAN (c. A.D. 220) in his Institutes, or at least attributed to him in JUSTINIAN's Digest:

"Natural law is that which nature has taught all animals; this law indeed is not peculiar to the human race, but belongs to all animals."(note 11)

Here the natural law seems to come much closer to the idea of animal instinct. Even today when people speak of the natural law they may sometimes be found to be supposing that it refers to what is natural in the sense of instinctual in us as against what may be thought of as planned and regulated and artificial; and when this happens they are at cross-purposes with others (and even with themselves in other phases of their arguments) who think of it essentially as the ideal and the reasonable.


Besides these two strands in the concept we may note much more briefly others also.

When Ulpian gave the definition just mentioned, it was within a tripartite division of law into natural law (jus naturale), the law of nations (ius gentium), and the law of the city (ius civile); he therefore contrasted natural law with ius gentium. But GAIUS before him had identified these two laws, and his account too was incorporated into Justinian’s compilation, with the result that there entered into the traditional concept of natural law in the whole complex notion of the ius gentium.(note 12)

It is not part of this essay to investigate what this involves nor to decide whether the origins of ius gentium lie in an empirically established lowest common denominator of the laws recognized by the peoples subject to Rome or in the more abstract consideration of a jus common to all people because founded upon "natural reason" (note 13) It is sufficient to have called attention to this further strand in the evolution of the idea of natural law.

1.3 Medieval writers on Natural Law

Yet another confusing element is to be found in the widely used definition given by the twelfth-century Italian monk and canonist GRATIAN. "Mankind", he says, "is ruled by two laws: natural law and custom. Natural law is that which is contained in the Scriptures and the Gospel." (note 14)

Taken at its face value this might seem to make natural law dependent upon Revelation, and though such a view can hardly be attributed to Gratian himself’ (note 15) a certain conjugation of the concept with the Decalogue and with Christian ethics is hence-forward fairly well in evidence; the natural law is thought of as "divine" without its always being clear in what sense this is to be understood.

In mentioning these various strands in the making of the concept it has not been my intention to be either exhaustive or to make them appear to be completely distinct one from the other. The different strands overlap one with the other, but they also introduce tensions and even contradictions within the concept, which it is necessary at least to be aware of in any attempt to handle the subject.

1.4 Post-medieval thinking on Natural Law

As for the developments of the concept after the Middle Ages - the ideas of natural law, for example, that lie behind the revolutionary movement of the eighteenth century - I make no attempt to trace these. This is not because they are not important in themselves, but simply because I am concerned only to give some account of the concept as it has entered the traditional teaching of the Catholic Church; and in this teaching the seminal influence has been that of St Thomas Aquinas.

I do not however propose to set out in any formal manner the teaching of Aquinas. Rather, I shall take him as a kind of guide and mentor in proposing what will be a personal statement of the concept of natural law that may be at once faithful to the role it plays in the Catholic tradition on this matter, and of relevance to the issues in which it is today customarily invoked in Catholic moral teaching.

That it is a matter of some importance to understand the concept can hardly be gainsaid when one hears it so constantly invoked in arguments about contraception, nuclear warfare, religious freedom and so forth. And quite apart from these applications, the concept has been given renewed attention as the result of the need to have some theory which will justify the rejection of unjust legislation. It may seem to many, and as I think rightly, that without an appeal to something like natural law, such proceedings as the Nuremberg trial have no rational basis.

The importance of the theory of natural law is that it affords the possibility of rebellion; it provides a court of appeal, and without it there is no court of appeal beyond the edicts of people. It is true that, merely because one law within a given legal system may be criticized by reference to other laws within the system, it cannot be argued that there must be some criterion outside the whole system whereby the totality of the laws may be criticized. This would involve the logical fallacy that because all the laws can be referred to some criterion, there is one criterion for all laws. But what I should wish to say is that the very possibility of any law being referred to any criterion, even within a legal system, implies that there is, within the legal system, a structure which makes possible critical scrutiny.

Or, more simply, the calling in question of the obligatory character of any given law raises the whole problem of the obligatory character of law, and this obligatory character within a legal system constitutes the kernel of the concept of natural law.


Part Two. Clearing up Misconceptions

2.1 Natural Law is not a law like others: it is the heart of all moral obligation

This leads to an observation of some importance. The fact that we use the word "law" in speaking both of natural law and positive law may easily lead us to suppose that such "laws" are in every respect the same sort of thing, laws standing side by side. The temptation then is to look for a natural law which functions in the same way as positive law (to look for a kind of written code "in the heavens" or "in people’s he arts" and so on), and upon finding that there is no such thing, and that, by comparison with positive laws, the natural law is vague and the subject of endless disagreement, to conclude that it simply does not exist.

But this would be a simple mistake, the result of a systematically misleading expression. For in fact to speak of both the natural law and positive law as "laws" is to do the same kind of thing as to speak of tables and chairs as objects or beings or things, and to speak of God likewise. If this leads us to think of God as one more thing alongside of and beyond things like tables and chairs, we are being systematically misled by the expression "object" or "being" or "thing". This is a "category mistake". Instead we should understand that God is interior to, and the very ground of possibility of, every "thing" that is.

Likewise, in speaking of natural law as "law" we should think of it not as lying alongside of, and somehow superior to, all other laws, but as that which is at the heart of, and constitutes the possibility, indeed the obligatory character, of every other law. In other words when we are speaking of natural law, we are in the field of ethics or morality rather than in that of legality in a narrow sense.

It is important to have made this observation for it goes some way to meeting the objection commonly made that natural law is so vague and so much the matter of endless controversy as to be useless in the practical business of reaching legal decisions or agreement on disputed points. The assumption from which this objection springs is that natural law is to fulfil the functions of positive law, only "more so" or in a higher order of justice; it is the objection of practical lawyers concerned with getting things settled. 16

But in fact this is not the function of natural law as such; for though the natural law may be embodied in directives of a more or less general kind, as we shall see, the point of describing such directives as belonging to natural law is not so much to call attention to their content as to the moral character of their obligatory force. The theory of natural law is a theory of what makes laws, not an easy substitute for making laws, for legislating.


2.2 Natural Law is not a law depending on revelation

Before going on to a positive description of what is meant in the Catholic tradition by natural law, it may help to avoid certain misunderstandings if we begin with certain disavowals.

First, though it is in some sense the law of God, and is often so referred to in Catholic documents, 17 the natural law is not divine law in the sense that it is dependent, in any necessary way, upon a special divine revelation.

2.3 Natural Law is not a distinct decision by God

Second, it is not the result simply of the will of God, in such manner that had God willed otherwise the law might have been quite different and opposite to what it is. This is, of course, to take up an attitude to the whole character of law and to deny that in the last resort it derives from an exercise of sheer sovereignty. It is to reject, for example, the definition of law by Austin (and earlier by Ockham and Gerson) as simply the command or imperative of authority.

2.4 Natural Law is not dependent on belief in God's existence

Thirdly, I believe it true to say that the concept of natural law is not dependent upon belief in God’s existence. Etiamsi daremus non esse Deus, even if we were to allow that God is not, as GROTIUS observed, the natural law would retain its validity; and, though I know of no passage where St Thomas entertains this hypothesis, Grotius had his medieval forerunners in making such an assertion; nor were they, in my opinion, out of step with Aquinas’ conception of the natural law in so doing.

Admittedly, the status of the natural law would in that hypothesis be considerably altered, for it would then have an ultimacy which, given the existence of God, it does not have; but its character as law would not be changed.

2.5 Natural Law does not imply obvious consensus

Fourthly, it is no part of natural law theory to hold that there is a whole range of human conduct which can be seen, with only a little good will, to be right. The dictates of the natural law may be, are, and may be expected to be a matter about which there is the utmost confusion and disagreement.

2.6 Natural Law may require 'unnatural' activity

Finally, not everything which can be said to be in one sense or another "unnatural" is against the natural law. Most human activity is artificial and yet may be required by natural law; and it is, in one of the commonest uses of that most ambiguous word "natural", very natural indeed to offend against the natural law.

If these disavowals appear sweepingly dogmatic, I must plead that I am not here concerned to prove them. I am only concerned to say that none of the things denied are necessarily implied by any and every theory of the natural law. That this is so I hope will become apparent from the account that we must now go on to give. For the moment I have been concerned simply to remove obstacles to understanding this account which might arise from a priori anticipations of what it must imply.


Part Three. Thomas Aquinas' understanding of Natural Law

3.1 Basic image to explain Natural Law

By way of beginning, at last, a more constructive account, I shall use an extremely crude analogy, but one that, because of its simplicity, may do more than a more sophisticated account to make its point.

Manufactured products, whether simple or more complicated, are as often as not accompanied, when they are bought, by the maker’s instructions or rules of how to use them. These rules are not arbitrary fiats of the manufacturer which might be entirely different from what they are. They tell the buyer how to get the best out of the product; if it is used in such and such a way, it will last, and perform its function well; if used in some other way, it will be broken, or give indifferent service.
What the manufacturer is doing is to tell the buyer what he knows of the nature of his product.

Admittedly, we have here to do with an artifact, and the maker’s knowledge is based on his having designed the product for a purpose. But his rules do not reflect this knowledge alone; they are to some extent based also on the knowledge he has of the materials used - they will stand up to certain usages while to others they will not.

There is some sense in which the rules listed by the maker are not simply written on his paper list of instructions. They reflect what may be said to be built into the products. In this sense they are the "rules" or "laws" of its very make-up; the "rules" of its nature.

Nor is it even necessary that a list of instructions should be provided. It would theoretically be possible for the buyer to examine the thing, take it to pieces and reassemble it, and arrive at the same set of rules; he would then have read them off the product itself.

All this provides an analogy, though only a partial one, to natural law. Instead of manufacturers’ products, we have to do with human beings.

3.2 Natural Law means our reason studying how nature works

There could, theoretically, be issued with every human baby rules for his/her proper "use" - describing the way he/she is to be used to get the best out of him/her, to see that, as a human being, he/she finds proper fulfilment. But in fact, of course, no list of rules is issued. It is left for people to discover for themselves the "rules" built into their nature as human beings, to discover how to use themselves if they are to get the best out of themselves and find their proper human fulfilment.

And by natural law is meant not these "rules" as built into them (my use throughout of inverted commas has been intentional, to call attention to the fact that such "rules" are scarcely properly so called) but these "rules" as recognized by people on reflection upon what it is to be human and to find human fulfilment.

3.3 Natural Law is reason assessing nature within the total human context

Here it is important to insist that "to be human" must be understood in the total human context.

Arguments for something’s being in accordance with or against the natural law often enough appear to forget this. One example may illustrate this point. What Dr. Rock (note 18) cites as "a typical statement of the conventional Catholic position" runs as follows:

"The reason why the artificial practice of birth control is immoral is written into the very nature of the sexual organs and the marital act itself. The sex organs were made by God to reproduce the human race. Only when husband and wife unite naturally is the union of sperm possible. Therefore the primary purpose of the marital act is the conception of human life." (note 19)

Apart from a good many things wrong with this argument as it stands, and the fact that if it proves anything it proves too much for it would be equally applicable to birth control applied to animals, the whole approach appears to me wrong.

For it seems to suppose that by a simple inspection of physical organs, rules can be reached for human behaviour. But man is not simply a complex of organs. "Human beings define themselves in relation to the world, and in relation to those around them." (note 20)

To discover what it is to be human and to achieve properly human fulfilment, account must be taken of the human being not simply as a biological object, not even simply biologically (which would introduce a whole consideration of his ecology), but in the specifically human dimension in which he/she enters into communication with others at a human level.

"Natural" to human beings is that which constitutes them not merely in isolation, but in relation to the whole world-for-humans which they create around themselves (the highly artificial world of civilization), and in relation to other persons who stand not simply as objects but as other subjects around them.

This is a point to which we shall have occasion later to return. It needs here to be made very forcefully because of the frequency with which it is overlooked in natural law arguments.


3.4 Natural Law is human reason not a 'rule of nature'

When we insisted earlier that the natural law is not to be taken as referring to the "rules" built into a man’s make-up, but to his recognition of these "rules", we touched, in fact, upon the difference between the natural law and what may be called "the laws of nature (if we may use the latter expression in a rather restricted sense). We may say that the "rules" built into the make-up of things - whether of inanimate objects, plants, animals, human beings - constitute in each the "law" of their nature.

But only in human beings, with their capacity to reflect upon and know themselves, can there be any question of natural law, the recognition for themselves of how they are to act; and only in their case, with their freedom of action, can there be a responsible following or deviation from the "rules" of his nature (and even this only to a limited extent).

Intermediate observations

It will now be seen more clearly why it was possible to say that the concept of natural law is not dependent on the existence of God. For whether a human being comes from the hand of a Creator or not he/she must be said to have some particular make-up.

It will also be seen in what sense, and in what sense alone, the natural law is the law of God. It is only to the extent that God has made the creature, and made it carrying within itself the "rules" of its make-up. So far as the natural law is a faithful recognition of these rules, it is the faithful reflection of the designs of God, or, as Aquinas says, a participation in the eternal law, which is the ordering wisdom of God. (note 21)

The analogy so far pursued is however a very insufficient one. We must now take account of two objections that may be made to it.

The first is that it would be very odd to say that a maker’s instructions were in any usual sense obligatory. However threatening the form of words he may use ('Don’t do this, Do this', etc.), all they amount to is this: 'if you wish to get the best service out of this product, act in such and such a way'. Such rules are, in the last analysis, descriptive rather than prescriptive.

The second objection to the account of natural law so far given is that whereas the natural law has traditionally been taken to be permanent and immutable, it may very plausibly be argued that human nature (prescinding anyway from the difficulty that the concept of nature presents to the contemporary mind) is in constant process of development according to his cultural evolution.


3.5 In Natural Law the first principle is the inclination to do good, specific conclusions are actions

I can do no more than sketch an outline of an answer to these objections. Certainly, in regard to the first, I do not wish to say that the natural law for man is simply to take the form: 'if you wish to get the best out of yourself, act thus'. To say this would be in fact to reduce "ought" to "is", the moral judgment to a matter of fact.

When St Thomas Aquinas speaks of law, he speaks of it as a dictamen practicae rationis, a dictate of the practical reason. And he constantly draws a parallel between the working of the practical reason and that of the theoretic or speculative reason.

As in theoretical reasoning we reach conclusions from premises, or what he calls first principles, so do we reach by practical reason conclusions from first principles. The conclusions of practical reasoning are for him decision as to action; (note 22) the first principles by which we reach such conclusions constitute for him the natural law, or the precepts of the natural law.(note 23)

Now, though this parallel is in many ways illuminating, it may be misleading if we draw it too closely. It is tempting to think of the process of practical reason going roughly as follows: "the good is always to be done; but such and such is good; therefore such and such is to be done."

But where this, I think, is mistaken is that it turns practical reasoning into just another piece of theory. And from this we can be saved if we notice that Aquinas elsewhere refers to the "conclusions" of the practical reason as actions - not just as decisions to act, still less as conclusions about what ought to be done.

He speaks, also, of the first principle of practical reasoning, as the end (finis) itself. (note 24)

What I wish to suggest is that if we are to understand him aright, the process of practical reasoning is not simply a parallel to theoretic reasoning with only the difference that it is concerned with things to be done. Rather, to put it extravagantly, it is "a piece of doing" - the outcome is action, while the initial principle is the bent (the inclination) of the will to the good, to its end or finis.

We do not start upon this process by a theoretic statement that the good is to be done, but by the will’s "going for" the good. It is true that the "bent" of the will to the good is within the perspective of a cognitive recognition, for it is not a blind impulse but consciously orientated to the good recognized as such; and it is true that given this conscious bent, the reason further intervenes to intimate that such and such conduct is in fact recognizably good. (note 25)

But the initial dynamism of the will’s "bent" to the good carries right through the process. Thus the "conclusion" is not a theoretic conclusion about what is to be done; rather that initial "bent" of the will to good, instructed by the reason’s intimation of what is good, carries through then and there to action, or at the least to a decision which is to be understood as already an inception of action rather than a piece of theory.

Now what this implies is that the "ought" judgment never reduces to a simple "is" assertion, and that basically there is an initial obligation arising from our natural bent to good (natural not in any sense contrasted with rational, for it is not blindly impulsive, but natural in the sense of being an ineluctable tendency of our human make-up). And, in fact, Aquinas does insist that though the precepts of natural law are matters of reason, they take place always within the dynamism of the will and are shot through with its force.(note 26)

This is why the "rules" built into human nature, unlike those in any other being, provide the basis for the obligatory character of natural law. It is not a question of "if you will achieve your end, you should do this", but "you are bent necessarily upon your end, and this you must do as the means you recognize".




'Theoretic reason' means the mind focusing on finding out what is true and what is not true.

'Practical reason' means the mind focusing on action: what ought to be done and what not.

3.6 The basic impulse of Natural Law is that good needs to be done, evil avoided

The parallel that we have been discussing between the principles of reasoning in the theoretic order and those in the practical order lends itself to another observation.

When Aquinas speaks of principles in the theoretic order he does so with considerable ambiguity.

* At times he speaks as if such principles were the premises in a piece of reasoning.
* But at other times his first principles are such as the principle of contradiction, of excluded middle, etc. Now from such principles it is impossible to derive any argument. The truth is that by first principles he may mean the fundamental axioms in any given field of enquiry.
* But at other times he means principles immanent to the whole process of reasoning - not premises in an argument, but the structure without which no argument would be coherent - not axioms but rules of thought.

Now rules one cannot get on without, and, to the extent that one is rational, one cannot be without. But the principles which constitute the premises of an argument, axioms, are a matter either of prescription or of notification from experience.

There is a parallel to this ambiguity in Aquinas’ account of natural law in terms of practical reasoning. When he speaks of it as constituting the first principles of practical reasoning he seems at times to think of it as comprising the rules without which no such "reasoning", or, in the light of what we have said, no such piece of action, can get under way - the purely formal rules therein involved.

It is in this sense that the first principle of all is that the good is to be done, evil avoided (and in all that follows it is necessary to take these rather intellectualist expressions as referring not to a theoretic judgment, but a shorthand expression to refer to the dynamic bent of the will under the guidance of understanding to which we have already referred).

Thus it is that Aquinas can speak of "the light of natural reason, by which we distinguish good and evil (qui discernimus quid sit bonum et malum), which belongs to natural law", (note 27) and can write, "The first principle of practical reason is founded on the notion of the good, the notion which is that the good is that which all have an inclination to (appetunt). The first precept of the law is therefore this: the good is to be done and pursued, the evil avoided." (note 28)

In other words, the basic rule of morality consists in the discrimination of good from evil; and without this there can be no decisions as to conduct nor any obligation attaching to them, any more than in the theoretic order there can be any possibility of reaching conclusions without accepting the rules of reasoning.

At this basic level it makes sense to say that no man can be without knowledge of the natural law. It is highly doubtful whether any human being (whatever his outward profession) can ever be denuded of this radical sense of right and wrong, or devoid of the urge to pursue that which presents itself to him in the guise of good, or avoid that which appears as evil. And if there were such a person, he/she would forfeit his/her claim to being human, and be, in the moral order, what in the order of theoretic truth is a lunatic, or an infant (and even lunatics and infants have at least the radical capacity for, in the one case, acceptance of the rules of reasoning, and in the other, discrimination between good and evil).


3.7 The "first principles" of Natural Law - on preserving life, bodily health and pursuing reason - which derive from the basic impulse and experience are general, not specific

But so far we remain at the purely formal level; from the rules of reasoning, or the rules of morality, no conclusions and no decisions can be elicited. These rules need to operate in a given content, and the most general content is supplied by "first principles" taken in the sense of axioms. Such axioms, apart from the case of purely formal sciences where they may be prescribed, are discovered in experience.

And thus it is that Aquinas will speak of the natural law as comprising, besides its purely formal rules, the broad recognition, based upon experience (of the most general sort) of particular heads of goods.

Such recognition constitutes the principles of natural law in the second sense of "first principles". These primitive recognitions of, and urges to, particular goods he classifies under three heads which we may call the good of individual survival, biological good, and the good of human communication.

"* First, there is in human beings an inclination to good according to the nature which they have in common with all substances . . . in accordance with this inclination everything by which the life of a human being is preserved, and its opposite held in check, pertains to the natural law.
* Second, there is in human beings an inclination to things which concern them more specifically according to the nature which they share with other animals: and
it is in virtue of this inclination that those things which nature has taught to all animals are said to be of the natural law; such as the intercourse of male and female, the education of offspring, and so on.
* Thirdly, there is in human beings an inclination to good according to the nature of reason, which is special to them; thus human beings have a natural inclination to know the truth, and to live in society: and so whatever pertains to this inclination pertains to the natural law." (note 29)

Upon these urges or primary recognitions of quite general goods in the concrete, the good is now no longer apprehended purely formally), one cannot, I think, immediately base principles such as "Thou shalt not commit suicide", "Thou shalt not practice birth control", "Thou shalt not lie", and so on, but rather upon principles of the form "some arrangements should be made for the preservation of life", "some for the organization of the family", "some for the organization of society", in each case leaving it open to further experience and enquiry what the arrangements are to be.

Or, as Eric d’Arcy puts it, (note 30) the primary precepts of the natural law are not of the form "adultery is wrong, murder is wrong", but of the form "sexuality demands some form of regulation", "there is a difference between killing a rabbit and killing a man".

And when this is understood, it becomes much more plausible to say that such primary precepts of the natural law "are everywhere identical, immutable and ineradicable".(note 31)


3.8 Natural Law comprises also specific conclusions deriving from the first principles, conclusions about which there can be confusion

But if this is the only content of the natural law, it provides us with singularly little guidance in human conduct, even though already what it does is not negligible, since it provides us in principle with the basic possibility of examining and justifying human decisions and conduct instead of leaving us to suppose that they are matters about which there can be no argument, and for which there can be no criterion of obligation.

However, St Thomas goes further than this. He thinks that from these quite general precepts we may derive others by way of conclusions. (note 32)

And if it seems that we have lost sight, now, of his description of the natural law as consisting of the principles of practical reasoning to exchange it for something that comprises also conclusions, we should remember that principles have to be thought of relatively to conclusions, as it were on a sliding scale. What is a conclusion in relation to higher principles may be itself a principle in relation to conclusions to be drawn from it.

The natural law has different levels; basically it consists of those highest principles which are simply given and indemonstrable - whether as the rules of moral conduct or as the primary axioms of an entirely general moral awareness; but it comprises also anything which may be derived, by way of conclusion, from such axioms, and which may serve in turn as principles in reaching individual decisions as to conduct.

In this way, the natural law is indefinitely extendable, as we come into fuller and fuller possession of what we see to be derivable from the original premises.

But, and it is important to notice this, such development is not to be had without constant reference to a wider and more sensitive assessment of experience; nor is it to be had without danger of making mistakes, and without exacting enquiry.

The process of practical reasoning is no more infallible, and no surer of its results, nor is it any more ready-made, than the parallel process of theoretic reasoning whereby we attempt to reach speculative truths. If, in pursuing more and more detailed conclusions within the body of natural law, we find greater and greater confusion and disagreement, we should be no more disconcerted at this than we are when we find ourselves beset by perplexities in the pursuit of truth.

But, just as our pursuit of truth is not to be abandoned as an impossibility and a futile waste of time merely because we find it difficult to establish what is the truth, so our accommodation to the requirements of natural law is not to be given up or seen as useless merely because we find it impossible in practice to reach agreement.

Truth is not less truth, and an ideal to be sought, for its not being adequately found; and the natural law is not less the law, and a court of appeal, for its not being adequately agreed.


3.9 The specific conclusions derived from Natural Law may differ from person to person according to specific circumstances

In relation to the conclusions to be drawn from the primary principles of practical reasoning the parallel with those drawn in the theoretic order may again however be misleading. Here St Thomas himself puts us on our guard:

"There is a difference between theoretic and practical reason. Theoretic reason is concerned with what is necessary, with what cannot be otherwise: truth is discovered in its special conclusions without exceptions, as it is also in its general principles. But practical reason, being concerned with human conduct, has to do with the contingent. And so, though there is a certain necessity about its general principles, the further it descends into detail, the more it may encounter exceptions. Thus in the theoretic order there is the same truth for everyone, though it may not be equally recognized by all except in its very general principles. But in the practical order there is not the same truth or practical rightness for everybody, as far as detail is concerned, but only in general principles (and even in those for whom there is the same rightness it may not be equally recognized by all).. ..
[For example] i
t is right for all to act according to reason. And from this it follows in detail that things borrowed should be returned to their owner. This is right for the most part (Ut in pluribus), but it can in some cases be harmful, and so against reason, as for example if what is returned comes to be used treasonably. . .
And the further one descends into details, the more does this happen. Thus the natural law in its first general principles is the same for all both as to what is right and in their recognition of it. But in relation to details which come as conclusions from those general principles, it is the same for all for the most part (both as to what is right and in their knowledge of it), but may, in some cases, admit of exception as to what is right because of particular circumstances as well as not being known to all."(note 33)

3.10 The detailed conclusions of Natural Law will change if the circumstances change

There are two important admissions made here. First, that to maintain a theory of natural law is not to be committed to the view that everything in it must be clearly recognized by all people. St Thomas envisages failure to recognize the more detailed requirements of the law as coming not only from inability to argue straight, but also from the effects of passion, lack of culture, and bad habits. (note 34)

Secondly, that what is laid down by the law has not a rigidly universal application.

All this prepares the way to our considering the second objection that we raised in connection with the analogy of the manufacturer’s list of rules. Is it not the case that human nature, upon which the whole elaborate fabric of the natural law is based, may change and develop? And may we not then say that what was once right, in changed circumstances no longer has application?

I think this question has to be given rather more sympathetic consideration than Catholic tradition has been inclined to give it in the past.

I have already insisted that when we consider human nature, consider what it is to be human and find human fulfilment, we must take human nature in its total dimensions. To be human involves being in a world-for-human-beings which is very largely of human beings' own making; it is to be engaged in a world of communication, taking communication in the broadest of senses to refer not only to linguistic communication but the whole network of artificial transactions and conventions that human beings in society creates about them.

Human fulfilment is to be judged not simply in biological terms, but in terms of the full realization of an individual’s personality in relation with other persons against the background of this network of communications. That will be right for each which enables each to fulfil themselves in this dimension, and that wrong which does not.

There is a sense in which the existentialist affirmation that human beings create their essence by the decisions they takes rather than that they come into the world with a ready-made essence represents a profound insight.

To be forever progressing is a characteristic of human beings; the world around them is their world, the world for them, the world of their own ceaseless making and realization. (note 35) And this seems to mean two things: first, that they have always new conclusions to draw from the general principles of the natural law, as they are confronted by new situations of their own invention; and secondly that conclusions earlier drawn may, in the changed circumstances, have no further application, or only a modified application.

It is not that the basic principles of natural law are subject to change; but that there can and must be new applications in detail, and that some applications that held in particular circumstances in new circumstances may no longer hold.


Meaning explained in the text!

3.11 The requirements of Natural Law are, therefore, changible in detailed applications

St Thomas himself seems, in spite of the weight of tradition in favour of the absolute immutability of natural law, to have adumbrated some such possibility of development:

"In one sense there is nothing to prevent change in the natural law; for much is added to it which is useful to human life, both by divine law and by the laws of people. And there may be change in the sense that something ceases to be of natural law which formerly was so. As far as its first principles are concerned it is entirely immutable; but as far as subsequent precepts are concerned, in respect of those which we have said to be closely related to the first principles as conclusions to premises, the natural law does not change as if what was right for the most part were not always so; still, it may change in some particular, and in some cases because of special causes hindering the observance of these precepts."

St Thomas admittedly has in mind only individual cases of exception; but it may be asked whether, in principle, his ideas may not be enlarged to cover wider "exceptions". This is a question that should at least be further explored.

3.12 The requirements of Natural Law are, therefore, changible in detailed applications

At the end of this perhaps too personal statement of the traditional concept of natural law,it may be asked whether I have not so diminished it as to make of little value. I have argued that it is not "law" in the same sense as positive law; that its primary injunctions are purely formal, amounting to little more than discrimination between good and evil; that its derivative precepts are either so general as to provide little guidance to conduct or else so disputable as to win no general consent; and that in its more detailed applications it may be subject to change and exception. Is there anything left?

I think the suggestion that there is not comes from asking and expecting too much of the natural law (as sometimes people ask too much of the existence of God, as if he were there to be a deus ex machina to solve all problems).

The natural law does not provide a ready-made yardstick by which to measure other laws; it is not an alternative code which may be consulted to find whether it contains the laws made by human lawgivers. If it were, there would be no need for the laws of people, except in those matters left open by