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"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.

Human Nature-Immutable or Mutable

by M. B. Crowe

published in The Irish Theological Quarterly. September 1963, vol. 30, no.3, pp. 204-231

The natural law is central in scholastic moral theory. The explicit, references to it in the magisterium of the Church have been multiplied in modern times; and when moral theologians characterize certain types of conduct, artificial birth prevention for example, as “against nature” or “unnatural” they intend to condemn such conduct in the clearest terms. The assumption is that there is a determinate “human; nature” against which human behaviour may be measured and' possibly found wanting. It is precisely this conception of human nature as an invariable, universal standard, that so many of our contemporaries find impossible to accept. In a celebrated passage Jean-Paul Sartre argues that classical metaphysics has been vitiated by une vision technique du monde, by the assumption that there is a God, artificer of the universe, whose ideas define the parts of the universe as the idea in the mind of the manufacturer of paper-knives defines the object he makes; there is, in fact, no God and, so, no divine idea to define “human nature”; man first exists and, then, is defined as what he makes himself.(1) Insofar as man has an essence he is freedom as opposed to “nature”; this same paradox, that the nature of man is not to have a nature, can be found also in Maurice Merleau-Ponty and in Gabriel Marcel.(2) Nor has human nature fared much better with the logical positivists. A. J. Ayer began his Language, Truth and Logic with a chapter on “The Elimination of Metaphysics” and followed it with a later one entitled “Critique of Ethics and Theology”; between them they were thought to have disposed of human nature as a metaphysical conception and to have shown that statements about human nature, being neither tautologies nor empirically verifiable, were strictly meaningless.(3) The only function left to ethical terms and propositions is that of expressing emotion; and the emotive theory of ethics can claim a respectable background in empiricism going back to Hume. Even if the more extreme views of Language, Truth and Logic have been abandoned, even by Ayer himself, the prejudice against metaphysics has not.(4) And even if human nature be allowed, any effort to base moral statements upon it comes under the ban of the “naturalistic fallacy”, ’purporting, as it does, to derive moral imperatives from factual propositions, or “ought” from “is”. Add to this the rejection of any unchanging human nature by the Marxist dialectic, the difficulties raised by developments in the study of evolution, in psychology and in cultural anthropology, and the indictment of “human 'nature” becomes formidable indeed. How far, one is led to ask, is the scholastic natural law based upon a totally unjustifiable “platonic” essence of man?


It is by now a commonplace to note that the word “nature” is one of the most ambiguous of philosophical terms. Lalande’s standard Vocabulaire technique et critique de la philosophie lists some eleven meanings for “nature” and thirteen for “naturel”.(5)

Raimundo Paniker, in 1931, recorded no less than twenty meanings for “nature”, meanings discussed and tabulated more recently by Philippe Delhaye.(6) In the context of natural law alone Erich Wolf listed nine meanings for “nature”,(7) But almost any book on the natural law can provide a similar exposure of the ambiguities in the term. More often than not it is taken for granted that this effectively disposes of any idea of an unchanging natural law. Norberto Bobbio, for one, has pointed out that “nature” is such an equivocal term that diametrically opposed laws have been thought natural and that a new Praise of Folly might be written by simply listing the institutions—slavery or liberty, private property or communism, polygamy or monogamy and so on—said to be “in conformity with nature”.(8) It would, however, be a great mistake to think that the scholastics were unaware of the possible equivocations of the word “nature”. St. Thomas’s handling of the word in the context of morals will be considered later in this paper; for the present it will suffice to notice an interesting reference to the matter in John Duns Scotus:

“. . . naturale est aequivocum et non uno modo dictum. Hoc apparet ex pluralitate illorum, quibus opponitur. Nam naturale uno modo opponitur libero . .. secundo modo naturale opponitur supernaturali. .. tertio modo naturale opponitur violento”.(9)

Still, while conceding that the word “nature” holds more than a few pitfalls, it would seem essential to maintain that there is a “human nature” which is the standard of natural morality; otherwise the entire system of natural law ethics, fundamental to scholasticism, crumbles. And therein lies the difficulty.

If there is a common nature, independent of the conditions of space and time, upon which natural morals are founded, then morals ought to be the same for all times and places. But in the experience of moralists no fact is more evident than the extreme diversity of moral ideas, codes and practice accepted in various parts of the world and during different periods in history. This fact, like the ambiguity of “nature” just referred to, has often been taken to be a proof of the relativity of morals. Some of the examples of moral diversity frequently quoted in this connection may be found in John Locke’s Essay concerning Human Understanding as part of his argument against innate moral ideas.(10) Modern writers tend to be cautious in assessing the different kinds of moral variation and even point out that some, if not all, moral variations are perfectly compatible with the acceptance of absolute standards. The conclusion of Morris Ginsberg’s 1953 Huxley Memorial Lecture “On the Diversity of Morals” is that “there is no necessary connection between the diversity of morals and the relativity of ethics”.(11) The diversity still requires explanation. There seem to be broadly three kinds of explanation:

“When St. Thomas finds himself in the presence of different moralities, of contradictory laws, of diversely organized institutions’, he neither regards every variation as an anomaly nor attributes all divergences to the same cause. The explanations scattered through his works may be grouped under three heads: 1. the influence of the passions; 2. the unequal development of reason, of insight and of civilization; 3. the diversity of conditions, of situations, and of circumstances”.(12)

The possibility of moral variations arising out of “passion” does not require much elaboration. Human nature, whatever it is, is not exclusively rational; there is an affective and emotional side, not to speak of the bodily aspect, that must be taken into consideration ’when human behaviour is studied. For this reason Aristotle (13) rejected the Socratic identification of virtue and knowledge and discussed at length the paradox of the incontinent man, the man who knows what is right and yet does the opposite.(14) St. Paul put it more concretely, and in a theological setting: “the good which l will, I do not; but the evil which I will not, that I do .. . but I see another law in my members, fighting against the law of my mind, and captivating me in the law of sin” (Rom. 7:19-23). St. Thomas accepted the position; for him it was a patent fact that men acted sometimes out of passion and in spite of knowledge: experiment patet quod multi agunt contra ea, quorum scientiam habent.(16) He repeats the point more than once when speaking of the natural law: aliqui habent depravatam rationem ex passione, seu ex mala consuetudine, seu ex mala habitudine naturae; sicut apud Gcrmanos olim latrocinium non reputabatur iniquum, cum tamen sit expresse contra legem naturae, ut refert lulius Caesar in libro de Bello Gallico.(16)

And even more striking is his insistence upon the necessity of moral precepts in the Old Law, brushing aside the objection that human reason ought to be able to discover these for itself:

ratio .. . propter consuetudinem peccandi obscurabatur in particularibus agendis; circa alia vero praecepta moralia quae sunt quasi conclusiones deductae ex communibus principiis legis naturae multorum ratio oberrabat; ita ut quaedam, quae sunt secundum se mala, ratio multorum licita iudicaret.17

Here the reference seems to be to something more than the ordinary influence of passion upon conduct; it is not the one gust of passion that extinguishes reason but the habitual bias that corrupts the objectivity of reason. And St. Thomas allows it full scope.

The second factor explaining moral variations is the caducity of human reason. The individual reason is fallible; we all make mistakes, in our practical decisions as well as in our theoretical conclusions. St. Thomas seems to have accepted Aristotle’s doctrine of the practical syllogism, moral decision being the conclusion drawn from moral premisses. He therefore mentions, side by side with the evil customs that corrupt good manners, the erroneous convictions that produce wrong conclusions: potest lex naturalis deleri de cordibus hominum vel propter malas persuasiones (eo modo quo etiam in speculativis errores contingunt circa conclusiones necessarias).(18) The deficiency of human reason, however, extends to more than simple error in the deductive process. There is the larger question of unequal development, not merely the difference between one individual and another, but, particularly, the differences between entire peoples at different stages of civilization. Jacques Maritain finds here the “law of the progress of moral conscience”, which he considers to be a most important law in the philosophy of history. He speaks, of course, of progress in the knowledge of the moral law, which does not mean that men necessarily behave better. He gives as examples of this progress the present-day awareness that slavery is contrary to the dignity of the human person, that prisoners of war have rights, that child-labour is intolerable, that labour itself has its dignity, that authority does not need to be ruthless:

“The sense of duty and obligation was always present, but the explicit knowledge of the various norms of natural law grows with time. And certain of these norms, like the law of monogamy, were known rather late in the history of mankind, so far as it is accessible to our investigation. Also, we may think that the knowledge of the precepts of the natural law in all of their precise aspects and requirements will continue to grow until the end of human history”.(19)

This conception of progress and development in moral ideas is one that must be carefully distinguished from the view that moral ideas are simply products of evolution. This will be seen in its place. Meantime, the idea of growth points the way to the third of the factors that, in St. Thomas’s view, make for variation in morals —diversity of conditions, situations and circumstances.

This factor proves to be the most radical of all in explaining why men have so differed, and still differ, in their moral convictions as well as in their moral behaviour. For it goes deeper than the blinding of reason by passion or prejudice, deeper than the inadequacy of human reason faced with the complexity of some moral situations, right down to the nature of moral reasoning and to the essentials of the moral order. Moral decision, in fact, differs essentially from the conclusion drawn from speculative premisses—this is where the practical syllogism breaks down—and the principles of morality do not share the kind of universality and permanence characteristic of speculative assertions. St. Thomas accepted Aristotle’s wise observation, at the beginning of the Nicomachean Ethics, that we should seek in each discussion only such precision as the subject matter admits—“it is evidently equally foolish to accept probable reasoning from a mathematician and to demand from a rhetorician scientific proofs”. With regard to “fine and just actions”:

“We must be content ... in speaking of such subjects and with such premisses to indicate the truth roughly and in outline, and in speaking about things which are only for the most part true and with premisses of the same kind to reach conclusions that are no better”.(20)

St. Thomas, in the Summa theologiae, puts this view to work with interesting results. He is discussing the question whether the natural law is the same for all men and he has, of course, to find an explanation for the evident discrepancies between men’s views of that law. His argument turns upon the difference between speculative reasoning, which proceeds from firm principles to necessary conclusions, and practical reasoning which, while it may be sure of its principles—si in communibus sit aliqua necessitas—has to do with contingent human action. In speculative matters truth is the same for all, although perhaps not equally available to all since it may require effort or ability to see it; it is true, for all who are capable of understanding, that the angles of a triangle are together equal to two right angles. But in practical affairs one cannot always say that there is truth, if only one could discover it; the very truth may be different for one man and for another. St. Thomas’s phrase is strong:

In operativis autem non est eadem veritas, vel rectitudo practica apud omnes quantum ad propria sed solum quantum ad communia; et apud illos, apud quos est eadem rectitudo in propriis, non est aequaliter omnibus nota.(21)

It is right and true for all, without exception, that one should act in accordance with reason. From this it follows that goods held in trust should be returned when the owner claims them; and so it happens in the majority of cases. But the exceptional case may arise in which it would be harmful and, consequently, irrational to return the goods—if the goods were required by their owner ad impugn nandam patriam.(22) In a word, the complexity of circumstances surrounding every human act is ineluctable and no law, not even the natural law, can cater for every contingency. The matter is plain in human law; no legislator can foresee all the possibilities his law may meet.(23) If he tries to do so his law becomes a thicket of qualifying clauses and—worse still—the more conditions it includes the greater is the chance of one or other being unfulfilled and so rendering the law itself nugatory.

St. Thomas, then, had a more flexible conception of the natural law than he is sometimes credited with. Passion and human fallibility as sources of moral diversity are compatible with a rigid view of human nature and of its law; but if differences in circumstances and situations can provoke differences in moral solutions it becomes less easy to be firm about nature and law. St. Thomas is, indeed, driven to say more than once in this connection: Natura Humana mutabilis est.(24) The phrase will repay closer scrutiny.


The assertion that human nature is mutable is one that might be expected to find an echo in quarters influenced by evolution and by situation-ethics (and both evolutionary theory and the approaches of situation-ethics have stimulated valuable developments in moral theory). Three recent scholastic writers, who exploit St. Thomas’s phrase about human nature being mutable, provide a convenient introduction to the topic.

The most recent of these authors is Ludger Oeing-Hanhoff. In an article entitled “Thomas von Aquin und die Situation des Thomismus heute”(25) his main concern is with the necessity of bringing Thomistic metaphysics into line with present-day developments, notably by abandoning elements that belong to the outdated Aristotelian physics. Towards the end of the article he refers to moral questions, to the problem of the historical changes in the natural law and in rig the moral obligations of peoples. The discussion of this problem, he suggests, may be linked with a phrase of St. Thomas: Natura humana non est immobilis sicut divina. Et ideo diversificantur quae sunt de iure naturali secundum diversos status et conditiones hominum.(26) This is, doubtless—Oeing-Hanhoff goes on—un mot a I’aventure in Thomistic philosophy; but it is very striking. It allows us to glimpse, side by side with the timeless and invariable metaphysical principle in man, something of the cultural and social environment in which man must develop, something of the changing status and conditions of human existence, the “historicity”, that justifies our speaking of a changeable human nature.(27)

Another author to make this point is Josef Fuchs who devotes: part of a chapter in his book Lex Naturae—zur Theologie del Naturrechts to the “Philosophical Concept of Nature”.(28) The difficulty for a theologian in making any statements about “human nature” is that, while our experience is of a human nature elevated to a supernatural order, fallen and redeemed, the concept of “mere nature” or “pure nature” must seem impoverished indeed, an abstraction, the invention of philosophers and incapable of verification. Still, the fact that “pure nature” is not directly accessible to us does not mean that there can be no definition of the physis of man or no conception of the moral order corresponding to this metaphysical definition. It is important to know which of the properties of human nature are rooted in the metaphysical definition and which are related to the supernatural condition in which man actually finds himself i.e. are put in human nature by God expressly as a substratum for the supernatural. Fuchs contends that, at least in some cases, we can establish propositions concerning the essence, meaning and obligations of human personality on the basis of natura pura. In other words, we can make assertions about human nature despite the fact that the nature we experience is not mere human nature. Our judgments about, say, property, sex, marriage, natural religion, relations with God can be soundly based upon the nature of man. Admittedly the exact “contour” of these judgments may be unknown to us in the sense that we may not know with certainty, or may not yet know, whether the elements in human nature giving rise to them belong to the permanent state of nature willed by God or to that de facto subject to historical change.(28) Further, philosophy, uninstructed by revelation risks erroneous interpretation of such propositions. But the possibility of arriving at valid conclusions about man’s nature, conclusions that will not later be revised by the recognition of his exclusively supernatural destiny or by the possibility of supernatural experience, must be insisted upon. Fuchs is critical of those theologians—he mentions Hans Urs von Balthasar and Henri de Lubac—who unduly decry the natural in man in favour of the supernatural.(30) The point of present interest in this whole discussion is the suggestion that the nature of man, even the metaphysical nature, must be taken in its historical setting.

In another work Fuchs further expands his views on these matters.(31) Once again he defends the conception of metaphysical nature and of the natural law against those who would minimize both, whether Protestants who deny their value or Catholics ducti tendentia unilateraliter supernaturali who do not sufficiently see their value. There is a human nature, accessible to reason, and a natural law corresponding to it. But this human nature may be considered either as the abstract metaphysical definition of man, animal rationale, or as the historical realization of that definition by God’s creative act. The supernatural setting of human existence is something that, logically, comes later.(32) The precepts of the natural law are reason’s conceptualizations and formulations of the moral order founded upon the Esse of man as man.

Some pages later Fuchs returns to the point and discusses the “historicity” of the natural law.(33) He remarks that, as the natural law is rooted in the personal essence of man, one might take it to be something quite static and “non-historical”. This, indeed, is the assumption of many opponents of the doctrine of natural law. It is not, however, an assumption that can be justified; for human nature, historically, is in some sense changeable and, in consequence, so is the natural law. And this is said explicitly by St. Thomas.(34) In support of the attribution of this view to St. Thomas Fuchs cites three passages. The first of these is the one given also by Oeing-Hanhoff—natura humana non est immobilis sicut divina; et ideo diversificantur ea, quae sunt de iure naturali, secundum diversos status et conditiones hominum.(35) The second, given as a cross- reference by Oeing-Hanhoff, is more explicit—illud quod est naturale habenti naturam immutabilem, oportet quod sit semper et ubique tale. Natura autem hominis est mutabilis.(36) The third is a passage in the De malo in which St. Thomas is discussing the need for human positive law. He says that there are two ways in which things may be said to be right and good:

uno modo formaliter; et sic semper et ubique sunt eadem, quia principia iuris, quae sunt in naturali ratione, non mutantur. Alio modo materialiter; et sic non sunt eadem iusta et bona ubique et apud omnes, sed oportet ea lege determinari. Et hoc contingit propter mutabilitatem naturae humanae, et diversas conditiones hominutn et rerum, secundum diversi- tatem locorum et tempomm.(37)

This last passage, because of the context in which it occurs, is the least useful to prove the point; it can be paralleled by a number of passages on the Summa where St. Thomas discusses the mutability of human law. He says, for example, that lex recte mutari potest propter mutationem conditionum hominum, quibus secundum diversas eorum conditiones diversa expediunt (and he quotes St. Augustine in support). But St. Thomas does not say here that human nature is mutable—the nearest he comes to it is when he says, in the reply to an objection, that the eternal law is unchanging, for it shares in the divine reason’s immobility and perfection; sed ratio humana mutabilis est, et imperfecta; et ideo eius lex mutabilis est. In fact, all through the discussion the contrast is made between the invariability of the natural law and the variability of human law.(38)

Still, St. Thomas’s statements that human nature may vary must be given their due weight; and this Fuchs proceeds to do. First of all, the natural law is more “historical” than positive law, that is, it is more adapted to historical conditions. This is another way of saying that the moral order, against which every human action in no matter what historical conjunction must be judged, is founded upon the Esse hominis; which Esse is either that of man as such or that of this man together with the circumstances, internal or external, in which he finds himself.(39) When the natural law is formulated in moral propositions its historicity becomes even more apparent—for it is seen that some elements in human nature are always present, others not. One can distinguish between the absolute and the relative or contingent elements and consequently between those prescriptions of the natural law that are absolute and apply at all times, and those others that apply only in those periods in which the elements in human nature to which they correspond are verified.

The position is illustrated by examples. Society—the State, say, or the family—requires authority (jus absolutum). In the condition of fallen nature the right of coercion is needed (jus relativum); it would not be needed if the original, supernatural harmony had lasted. Again, the family living wage is owed in the social and economic conditions that obtain today (jus relativum) but not however, under other possible conditions. What is required in all conditions (jus absolution) is that a just wage be paid; what is a just wage depends upon circumstances. Fuchs concludes this argument with two observations: (a) man’s nature absolutely requires this possibility of laws relative to the circumstances i.e. it is equally necessary that authority be not coercive in the state of original harmony and that it should exercise force in the state of fallen nature; (b) the relativity here described may be attributed to the inadequacy in the formulation of these laws; properly and fully expressed, the law is absolute e.g. that society requires the right of coercion when necessary for harmony. Finally he remarks that, original sin must he counted the greatest factor introducing the kind of change in the status of man to which natural law must be related. Some of the Fathers called the natural law relative to the condition of original justice primary natural law, and that relative to man’s fallen state secondary natural law—but others use a different terminology, or use the same terms in a different sense. The fact to appreciate is that many of the prescriptions of the natural law are relative to our fallen nature; they presuppose a sin that has entered the world and are, in fact, the sign of it. Examples are the right of coercion already mentioned, slavery (in certain conditions), private property,(40) the liceity of material co-operation in evil in given circumstances, broad mental restriction as permissible sometimes.(41)

It is now possible for Fuchs to face the problem of the mutability or immutability of the natural law in the light of his extremely nuance doctrine of human nature. It is clear, he says, that the natural law is neither intrinsically changeable, nor, properly speaking, extrinsically dispensable. This is true absolutely for the absolute precepts; and for the relative precepts it is true as long as the conditions of nature, to which they relate, persist. It is not unfair to say, then, that the natural law is in a sense mutable and in another sense immutable; mutable in the sense that its incidence is conditioned by the circumstances of human nature, immutable in that the intrinsic ratio moralis does not change. The formulations of the law frequently neglect the conditions that ought to be expressed, if the law is to be absolute. Hence the apparent difficulties or dispensations in the wide sense. “Thou shalt not kill”, for example, is not adequately formulated as a precept of the natural law, for it says nothing about killing directly or by private authority and, so, does not meet the cases of lawful self-defence, capital punishment, just war or divine authorization as in the case of Abraham with Isaac.(42)

A third contemporary scholastic, writing on the mutability of human nature mainly from the point of view of cultural anthropology, provides a most interesting commentary on the kind of discussion just summarized—C. Fay who, in an article entitled “Human Evolution: a Challenge to Thomistic Ethics” chides the reluctance of Thomistic ethicians to come to terms with evolution and anthropology.(43) The article makes certain assumptions: (a) that evolution provides a partial explanation not alone of the development of the human body, but of much of human culture; (b) that human evolution is “bio-cultural” i.e. both organic and super-organic; and (c) that it is meaningful to speak of progress in human as well as in organic evolution. Fay’s finding is that, in general, the evolutionary approach confirms and complements the traditional conception of basic, unchanging principles in nature expressed, however, with different modalities.

He begins by describing the mutual relations of bodily and cultural factors in human evolution and justly remarks that this interplay of the organic and the “more than organic” is precisely what a Thomist, given his theory of the soul, ought to expect. The fact that man has evolved in this fashion shows that he has a nature, and, so, an end, different from that of brutes. In the course of evolution life is lived at ever higher levels; but no essentially new mode of activity has arisen since Zinjanthropos. The changes introduced as man evolved are accidental to his nature as a rational animal—a more upright posture, a less simian face, a central nervous system better organized for symbolic life. In contemporary humans there is abundant evidence for a common nature, despite racial and cultural diversities; language, technology, family, art, religion, are the universal traits of cultural life. These traits vary greatly—and some of the variations are more significant than others—but there is a limit to variation. Up to the present the changes introduced by culture in the direction and pace of human evolution worked, for the most part, unconsciously-the genetic mechanisms involved were not understood. Work at present being done on genetics may yield the knowledge necessary to regulate the further course of evolution—which is a possibility that may present new problems in moral philosophy. This is an aspect to which Fay returns later in his paper.(44) Before coming to it, he examines the effects of “bio-cultural evolution”, which modifies human nature as it concretely exists, so that “its signification for ethics involves some sort of evolution in the sphere of morals”.(45)

The natural law is based upon man’s nature; moral goodness is conformity to human nature as it actually exists, i.e. as affected by the conditions of time and place. In the course of bio-cultural evolution such conditions have modified—even radically modified— human nature. Primary urges, like those towards food and sexual activity are differently experienced, even by contemporary men, as a result of differences in cultural conditioning. If the family, for example, represents a universal human situation, its determinate character is due to the particular circumstances obtaining when and where it is founded.(46) In general, human morality has its universal and invariable aspect and its aspect relative to this or that particular culture. The conflict is more apparent than real for it is simply a consequence of viewing human nature either abstractly and universally (and, so univocally common to the entire human species) or concretely and realistically existing in individual men (and, so, subject to bio-cultural evolution as well as to the individuation by matter). In the first case the natural law will be invariable; in the second variable as is the nature on which it depends.

At this point Fay cites St. Thomas’s phrase: Natura autem hominis mutabilis est (47) and suggests that here at least St. Thomas is taking the second of the above views of human nature; further, this view would be more prominent if St. Thomas were writing today. For some of the changes introduced by bio-cultural evolution

so alter the meaning of human knowledge and power (for example, agricultural and industrial revolutions), so transform relations between men and men (the urban revolution) and between man and nature |(atomic energy, polymer chemistry) that certain acts which were formerly good become bad and vice versa. I do not deny that the species of morally significant acts are determined in the light of universal human needs which are stable: lying, stealing and murder are bad of their very nature, precisely because they frustrate universal human appetites. But I do - deny that the species of moral acts is determined exclusively in the light of such needs; the species of good and bad acts are also determined by a constellation of biological and cultural conditions and emergent needs Which are both variable and relative.(48)

The changes introduced by bio-cultural evolution may be accidental in the ontological sense; but morally they may be extremely important—as the ontological accident of relationship makes the same act with one person adultery and with another fornication. One example of a change introduced in evolution is provided by social organization, at one time based exclusively upon kinship. In a modern society it would be wrong to favour relatives in the distribution of offices, whereas formerly it was not only right but necessary. The difference is in the different ways in which men existed then and now, the changed historical situation. There are, nevertheless, some things that can be judged irrespective of the cultural situation, so that an individual in one culture can correctly judge an action performed in an alien culture as morally evil, despite his unfamiliarity with the cultural surroundings of the act. This is because as well as the changing factors stressed by bio-cultural evolution there are also universal and unchanging factors:

Every society forbids lying, murder and stealing because of needs experienced by all men. But some acts are regarded as unjust homicide or theft in one culture but not in another: nevertheless, a stranger to a certain culture can ordinarily recognize that an act of theft, say, is stealing and is unjust; and he disapproves in the light of appetites shared with the members of the alien culture.

There are cross-cultural parallels in human appetition, and these parallels impose limits on variability and evolution in morals .. .(49)

These view's of Fay on the mutability of human nature are worth considering at some length because they represent an interpretation of evolution sympathetic to the demands of a natural law ethics; most evolutionary approaches to ethics are totally destructive of any system like the Thomistic one. Fay’s conclusion should be taken to heart, that human needs and acts are proportionally similar rather than univocally the same, that, while there are profound similarities in human life and its moral requirements, “to come to grips with similarities in moral philosophy will require a more extensive use of the data and theories of the sciences of man than ethicians have been accustomed to”.(50)


It is clear that there are certain advantages in being able to say, that human nature is “mutable”; and, for a Thomist, decided advantages in being able to quote St. Thomas in support. But it may well be pertinent to ask whether a very few texts of St. Thomas are not being pushed too hard in this matter. Only three texts have been adduced by the authors mentioned in the previous section. These texts—and one may add another natura nostra variabilis est unnoticed by those authors—have in common that they figure in replies to objections.(51) Oeing-Hanhoff, as has been seen, concedes that St. Thomas’s statement that human nature is mutable is hardly more than an obiter dictum. It is a just observation when account is taken of the enormous number of references to “nature” in St. Thomas and the great number of such references in the special context of human nature and natural law.(52) The significance of passing references to mutability must be measured against the overwhelming weight of emphasis upon the immutability of human nature and the consequent invariability of the natural law. At the outset of his career, in the De ente et essential(53) St. Thomas defined “nature” in terms of immutability as “the essence of anything according to which it has an ordination to its proper activity, for nothing lacks its proper operation”. In his major discussions of the natural law—even when he has to take account of moral variations including those biblical difficulties like the polygamy of the Patriarchs, the spoliation of the Egyptians in the exodus or the marriage of Osee to “a wife of fornications” which so exercised the medieval theological mind—St. Thomas tries to save the immutability of human nature. Thus in his first full-dress discussion of the natural few he defines it in terms of the intrinsic teleology of human nature—Lex ergo naturalis nihil est aliud quam conceptio homini naturaliter indita, qua dirigitur ad convenienter agendum in actionibus propriis,! sive competant ei ex natura generis, ut generare, comedere et hr.jusmodi,. sive ex natura speciei, ut ratiocinari et similia.

His solution of the difficulty of the Patriarchal polygamy turns, then upon a distinction between the primary and the secondary ends of nature in marriage; polyandry, as contradicting the primary ends, is intolerable; but polygamy (perhaps one should say, more properly, polygyny) is only against the natural law in an attenuated sense for it is reconcilable with the primary, although not with the secondary, ends of nature and might, consequently, in given circumstances, be tolerated by God. A similar solution is offered to the problem of natural law and the Old Testament bill of divorce; inseparability is imposed, not by the primary but by the secondary ends of nature in marriage; exceptional cases, in which the spouses are separated, are therefore conceivable.(54) The finer points of the distinction between, the primary and the secondary ends of nature—a distinction that St. Thomas seems to have been the first to present in this form which has commended itself to scholastic moralists ever since—are not the issue at the moment; suffice it to say that the solution it affords to the problem of certain vagaries in Old Testament morality, does not amount to a statement that human nature is variable. That phrase is incidental, in the reply to an objection.(55) Nor, in the Contra Gentiles (55a),when he treats of actions that are good or evil, “by nature”, does St. Thomas say—he seems rather positively to exclude the suggestion—that human nature is mutable. And in his last major work, the Summa theologiae St. Thomas’s preoccupation is likewise with the immutability, not the mutability, of human nature.

The references to a mutable nature, then, are quite exceptional. Each must, therefore, be seen in its proper context. The first of them, chronologically, is that found in the Supplement to the third part of the Summa; for, as is well-known, this work was left unfinished by St. Thomas but was completed after his death by the expedient of taking the appropriate passages from the Commentary on the Sentences and shaping them, by a scissors-and-paste method to the plan he had already outlined.(56) One must not forget that this Supplement to the Summa of St. Thomas’s maturity really represents the thought of his first years as a professor, twenty years before. The phrase: Natura humana non est immobilis sicut divina is here taken, like most of the Supplement, from the Commentary on the fourth book of the Sentences of Peter Lombard.(57) St. Thomas quotes, as his source, the seventh hook of Aristotle’s Nicomachean Ethics circa finem.(58) The passage is one of those in which Aristotle discusses the status of pleasure. He is making the point that, if our nature were unchanging like the Divine Nature, the same thing would always please us; but, since we are changeable beings, what gives us pleasure now may not do so at some future date. The point is not without its relevance for the present discussion; but St. Thomas hardly develops it. Nor does he develop it when, much later in his career, he comments explicitly on this passage; his commentary is confined, as is so frequently the case, to eliciting the literal meaning of Aristotle’s statement and does little to stress the mutability of human nature.(59)

There is, however, another passage in the Nicomachean Ethics that might seem more promising. It occurs in the fifth book, where Aristotle draws the distinction between natural and legal justice, natural justice having everywhere the same force (“as fire burns both here and in Persia”) while legal justice varies from place to place. It must seem slightly paradoxical that this passage should inspire St. Thomas to say—it is his next reference in the Commentary on the Sentences to a changeable human nature—natura nostra variabilis est.(60) But in its context the phrase is less radical than might appear. It comes in the discussion of polygamy, where St. Thomas meets the objection that a genuinely invariable natural law if it at any time forbids polygamy (as it now does) must always have forbidden it. The reply—designed to cater for the Old Testament practices—is that while the natural law is always and everywhere the same it may per accidens fail in its application. So, as Aristotle said, the right hand is by nature stronger than the left semper et ubique, yet not so as to exclude the possibility of one’s becoming ambidextrous. Indeed, in his later ex professo commentary on this passage St. Thomas points out that, since we are not separated substances with unchanging natures, there is something changeable in our nature: apud nos homines, qui sumus inter res corruptibiles est aliquid quidem secundum naturam, et tamen quicquid est in nobis est mutabile, vel per se vel per accidens. What is natural is what happens for the most part—ut in pluribus, sed ut in paucioribus deficiunt—as the restoration of entrusted goods is almost always a natural duty, but occasionally not.(61)

To return, however, to the Commentary on the Sentences, it should be noted that St. Thomas relates his phrase about human nature being variable to the well-known Aristotelian schema of the degrees of natural necessity.(62) There are those natural events that happen semper and cannot be impeded; there are those that take place frequenter and meet with occasional obstacles; and, finally, there are those that take place raro. In this triplex cursus rerumevents of the first class are causa et origo of those of the other two classes. So, for example, the invariable motion of the heavenly bodies is responsible for weather conditions (e.g. rain) which, in turn, provide the occasion for digging one’s garden and possibly unearthing a treasure! The illustration depends too much upon Aristotelian physics to hold much appeal for the modern mind. Still something can be learned from it; St. Thomas’s insistence that the natural law can be assimilated not alone to the invariable but also to the frequent course of nature (which admits of obstacles or exceptions) is not really an admission that natural law varies. Rather it is that the circumstances in which human nature finds itself that vary.(63) This may be gathered from another passage in the Commentary on the Sentences, where St. Thomas discusses the possibility of dispensation in the commandments of the Decalogue. The spoliation of the Egyptians and the marriage of Osee are inevitably mentioned. St. Thomas meets such difficulties by saying that what happened was that God changed the subject-matter of the precepts about property and marriage so that they no longer applied: Potest tamen Deus in aliquibus factis conditiones contrarias decalogo auferri, qui et naturam mutare potest.(64)

The passage from the Quaestio Disputata de Malo cited by Fuchs occurs in the article on indifferent acts.(65) The thirteenth objection purports to show that all acts are, in themselves, indifferent and that there can be neither natural justice nor injustice (for such ought to be the same always and everywhere whereas it is evident that what is just or unjust depends upon time and place. St. Thomas’s reply, as has been seen, involves distinguishing between the ways in which a thing may be said to be just and good, namely formally or materially. What is formally just is invariable; for the principles of justice, found in natural reason, do not alter. Materially, however, what is just may vary on account of the mutability of human nature and the different conditions of men and things, of time and place. In such circumstances it is left to the law to settle what is just. St Thomas’s example is taken from Aristotle’s discussion of the dikaion phusikon in the Nicomachean Ethics.(66) The tenor of the whole reply to the objection in showing the need for positive law has already been noticed; for this it was not, strictly, necessary to say that human nature is mutable—it would have sufficed to say, as St. Thomas does elsewhere, that human nature finds itself in changeable conditions.

This last remark applies also to St. Thomas’s final reference to a mutable human nature in the Secunda Secundae. Here it is once again a question of justifying the existence of a law based upon nature and, at the same time, of explaining why it does not cover all possible contingencies. The article is headed: Utrum jus convenienter dividatur in jus naturale et jus positivum,(67) The first objection is that in human affairs nothing immutable is found and, consequently, there cannot be a natural law. In his reply St. Thomas states that human nature is mutable; from which it follows that what is “natural” to man potest aliquando deficere. He gives in support the example we have seen before, that of the obligation of rendering up goods held in trust. This would always be a duty si ita esset quod natura humana semper esset recta. But it does happen from time to time that, because of the depraved will of man, a case will arise in which such goods should not be given back, lest the perverse will of man abuse them ut puta si furiosus vel hostis reipublicae arma deposita reposcat.(68) Here, it will be noticed, the mutability of St. Thomas seems to have in mind is that which makes possible a change in the will of the depositor, usually well-intentioned about the use to which he will put his property but possibly ill- intentioned. This is not quite the same as the objective mutability of the situation; still less is it a mutability in human nature as such. Cajetan’s commentary on the passage is instructive. Three things, he says, should be noted (1) the sense of the maxim: Naturale esl immutabile; (2) the reason why a deposit should sometimes not be returned; and (3) the fact that the change from justice to injustice in the rendering of a deposit and in similar matters assignatur ex parte alterius, ad quem dicitur iustum; ex mutatione namque ipsius mutatio fit in actu reddendi. From which Cajetan derives the advice— Et hoc ideo, vir speculative, specialiter notare debes—that it is important to distinguish between the case when what is just varies (as a result of a change in the ordo ad alterum) and the case when the exhibition of justice is prevented (by reason of something in the agent concerned).(69)


So far it has been suggested in this paper that St. Thomas, perfectly well aware of the need for meeting the difficulty of moral variations, left room for a certain flexibility in moral judgments appealing to nature; that the phrase natura humana mutabilis est appears in this connection, although rarely and in a passing way; and that closer examination of those references counsels prudence in placing reliance upon the phrase as it stands. It may help at this stage to indicate how some contemporary scholastics, apart from those already mentioned as invoking the phrase about human nature being mutable, see the basis for flexibility in moral judgments. It is, to some extent, a matter of terminology. But the terms chosen by different writers to draw out what is held to be implied in St. Thomas’s principles may be instructive.

The problem is still the same one: in what sense is “nature” invariable and in what sense variable? One obvious way of answer¬ing the question is by a distinction between “abstract nature”, which is quite invariable and “real” or “concrete nature” which is not. This is, in effect, what authors like Oeing-Hanhoff, Fuchs and Fay say when they use terms like “historicity” in connection with the natural law, or when they refer to the “concrete and realistic” consideration of human nature. But other authors who use the same terminology—“abstract” as against “concrete” or “real” nature— seem to think of the distinction more in terms of changed conditions in which nature finds itself than in terms of a changed or changing nature. For some the distinction between abstract and concrete may not involve much more than the acceptance of the common doctrine about universals, namely that abstract human nature does not exist except as individualised—and that individuals are irreducible. This takes one back to the metaphysical distinction between essence and existence. Essences are invariable per se; but as concretely existing they may change per accidens ad corruptionem individui.(69a) This same universal-individual distinction has been used in a rather different way in connection with the natural law by Heinrich Rommen; individual institutions, marriage for example, may be regarded as more or less imperfect embodiments of the ideal essence; and progress consists in the approach towards the perfect realization of the essence.(70) The metaphysical basis for this kind of thinking is found in the distinction between potency and act.(71)

It should be noticed, however, that authors such as those just referred to are not usually content to have indicated the basic reason for a certain mutability in the natural law; the reason for actual variations needs to be stated. It is not enough to say simply: Natura Humana mutabilis est. That phrase may be a convenient compendium of doctrine, as no doubt it was for St. Thomas too, but the variations in the natural law are explained on lines like those of St. Thomas, namely as the influence of “passion”, the fallibility of human reason or, most important, the complexity of the material with which moral reasoning has to deal. One is struck by the frequency with which St. Thomas’s example—which St. Thomas himself borrowed—of the obligation of returning entrusted property is used to illustrate the latter point. Here is an instance, according to Manser (to take one author), in which the matter of the precept changes. (72) This is, of course, the basis for the dispensatio improprie dicta often invoked to explain the moral difficulties in the Old Testament like the spoliation of the Egyptians or the sacrifice of Abraham; God’s supreme dominion over life and property can “change the material of the precept”. But such divine interventions apart, the matter to which natural law precepts applies is contingent and variable inasmuch as situations are contingent and variable; and some at least of the precepts of the natural law, frequently called secondary precepts, vary according to such circumstances. This is not a novel explanation, even in St. Thomas. It can be discovered in St. Augustine and the idea was developed by more than one writer in the interval between him and St. Thomas.(73) The corollary is that precepts of the natural law may be more or less adequately formulated. So, it is pointed out, the rules of the natural law when adequately formulated are invariable. Josef Fuchs makes this point in the course of his discussion of variation in the natural law;(74) and it is instructive to compare his handling of it with the more conservative approach of Ludovicus Bender. Having proved the existence of a natural law, Bender meets a number of objections, including the objection that, since all jus is subject to evolution there can be no such thing as a naturale jus (this being ex hypothesi invariable). His reply is entirely unambiguous—nos simpliciter negamus maiorem—those who try to show that all jus evolves, appealing to history, are mistaken. Historians should confine their attention to positive law, which does evolve.(76) In the following section, treating of errors, Bender reafiirms this position categorically. Nature is immutable; hence natural law is immutable. The rules of natural law are founded upon the unchanging nature of things and in no way upon the changing circumstances in which individual natures may find themselves placed.(78) Nevertheless haec immutabilitas bene est intelligenda! The precept: Thou shalt not kill is not, as it stands, adequately expressed and is not invariable. In order to exclude the cases of lawful self-defence and capital punishment, where killing is justified, one should say: Thou shalt not kill an innocent person.(77) Bender then proceeds to give the common doctrine about secondary precepts of the natural law, which may admit of exception, and primary precepts, which remain unchanged. The explanation lies in the difference between the way in which speculative and practical reason work from principles to conclusions. In the practical reason the conclusions, or the secondary principles, are valid and good, but allow exceptions. The principle that a man’s property should be returned to him is a good principle and almost always applicable; but it is not applicable when a madman looks for the restoration of his sword. This is not, Bender says rather disingenuously, mutatio in the strict and proper sense; the natural law absolutely and immutably prescribes that deposits be given back except in such exceptional cases!(78) It is clear that the realization that there is a difficulty about adequately formulating natural law precepts does not necessarily involve a flexible notion of human nature.

It can, indeed, be argued that on this thorny matter of the rule of natural law and the exceptional case to which it does not apply St. Thomas was more influenced by the Platonic conception of the idea and the singular than by the Aristotelian. For Aristotle the perfection of the rule was in its application to individual cases; for Plato the individual case is thought of as falling short of the ideal.(79) If this is so then there is even less reason than one suspected for thinking that St. Thomas would stress that human nature is mutable; if human nature is thought of as a Platonic form, imperfectly imitated by individuals, the exceptions to moral rules are laid at the door of the circumstances that prevent individual human nature from measuring up to the ideal.

Enough has been said to show that widely differing approaches are possible, within the scholastic tradition, to the problem of moral variations. A fuller study would require to take much greater account of the theological fact of original sin—important for its effect upon human nature and for its commanding the attitudes of many of the Fathers about human nature. This study, however, has had the more modest aim of examining some representative tendencies in contemporary scholastic writers faced with this capital problem. It does seem as if certain errors of our time, situation-ethics or exaggerated views about the scope of evolution for example, have had the beneficial effect of focusing attention upon weak points in the traditional doctrine. This is hardly surprising; error normally contains a germ of truth. An awareness of the contribution of new studies, such as that of cultural anthropology, must help towards a better-balanced and more valid, and in consequence more effectively defensible, conception of human nature and natural law. Such a conception may, indeed, be implicit in St. Thomas’s handling of the theme of variations in morality; but it needs to be drawn out and exhibited in a dress that will appeal to modern speculation. Hence the great value of a careful study of the “historicity” of the natural law, such as Josef Fuchs provides. Hence, too, the danger (although it is not suggested that any of the authors referred to has fallen into it) of making uncritical use of St. Thomas’s phrase that human nature is mutable as if it solved everything. The phrase is of great interest but to exaggerate its import would be imprudent as well as facile.



1. J.P. Sartre, Existentialisme est un humanisme, Nagel, Paris, 1959, pp. 17-22.

2. “ .. cette nature de la conscience qui consiste a n’avoir pas de nature"—Maurice Merleau-Ponty, Phenomenologie de la perception, p. 499: "Ce n'est pas 1'essence en tant que nature que j’atteins dans le toi. En efiet, en traitant l’autre comme iui je reduis l’autre a n'etre que nature; un objet anime qui fonctionne de telle facon et non de telle autre. Au contraire, en traitant I’autre comme toi, je le traite, je le saisis comine liberte, car il est aussi liberte et non pas seulement nature”—Eire et avoir, p. 154. Both passages cited in P. Foulquid-R. Saint-Jean, Dictionnaire de la langue philosophique, Paris, Presses Universitaires de France, 1962, s.v. "Nature”.

3. A. J. Ayer, Language, Truth and Logic, London, Gollancz, 1936, ch. 1 and 6. Cf. M. Warnock, Ethics Since 1900, Oxford University Press, 1960, pp. 79-118.

4. "... a glance at the history of natural law will be more helpful than epistemological argumentation to see the arbitrariness and emptiness of metaphysical speculation. .Strictly speaking, metaphysical assertions do not admit of being disproved, precisely because they disport themselves in a sphere beyond the reach of verification”—A. Ross, On Law and Justice, London, Stevens, 1958, p. 258.

5. 8me eddition, revue et augmcntce, Paris, Presses Universitaires de France, 1960, pp. 667-673; cf. J, C. Piguet, Le vocabulaire intellectuel, Paris, Centre de documentation universitaire, 1957, p. 67. Having given nine senses of “nature” Piguet concludes— “L’emploi des termes ‘nature’ et ‘naturel’ exige les plus grandes precautions”. Cf. also Foulquie-R. Saint-Jean, Dictionnaire de la langue philosophique, I.c.

6. 6 R. Paniker, El concepto de nataluraleza—analisis historico y metafisico de un concepto, Madrid, Consejo superior de investigaciones cientificas, 1931; Philippe Delhaye, Permanence du droit naturel, Louvain, Nauwelaerts, 1960, Introduction, pp. 9-21.

7. Das Problem der Naturrechtslehre, Karlsruhe, Mueller, 1955.

8. “Le disaccord sur le point de dipart se ripercute dans le riponse que les jus naturalistes ont donnie i la question: ‘quels sont les droits ou les institutions qui. doivent etre consideres comrae naturels, et quels sont ceux qui ne doivent pas I’etre?’ Une liste complete des opinions en cette matiere pourrait constituer, comme on l’a observe plus d’une fois, le sujet fascinant d’un nouvel eloge de la folie”.—N. Bobbio; “Quelques arguments contre le droit naturel” in Le droit naturel, Annales de philosophie politique, III, Presses Universitaires de France, 1959, p. 181.

9. Reportata Parisiensia, IV, d. 43, q. 4, scol. 1, nn. 2-5. Cf. David Hume, Treatise of Human Nature, Book III, Part I, section 2 (ed. L. A. Selby-Bigge, Oxford, 1888, pp. 473-6) where the exploration of the ambiguity of "nature” takes the same form— Nature "as oppos’d to miracles”, “as oppos’d to rare and unusual” and “as oppos’d to artifice”. .

10. Book I, ch. 3, n. 9; cf. ibid., n, 10—“He that will carefully peruse the history of mankind, and look abroad into the several tribes of men, and with indifference survey their actions, will be able to satisfy himself that there is scarce that principle of morality to be named or rule of virtue to be thought upon. . . which is not, somewhere or other, slighted and condemned by the general fashion of whole societies of men, governed by practical opinions and rules of living quite opposite to others”. Pascal had put the matter even more vividly, a generation before Locke—“Le larcin, l’inceste, le meurtre des enfants et des peres, tout a eu sa place entre les actions vertueuses” (Pensees, n. 294, Cf. L. Brunschvicq, Blaise Pascal—Pensees et Opuscules, Paris, Hachette, 1956, for parallel passages in Montaigne, Voltaire and Charron). Moderns, e.g. K. E. Kirk, Threshold of Ethics, London, Skeffington, 1933, p. 72, like to cite Westermarck’s Origin and Development of Moral Ideas in support of this position.

11. M. Ginsberg, On the Diversity of Morals, London, Mercury, 1962, p. 97.

12. S. Deploige, Le conflit de la moral et de la sociologie, cited in H. Rommen, Natural Law, St. Louis & London, Herder, 1947, p. 227, note 19.

13. Nicomachean Ethics, I, 13, 1102a26-1103al0.

14. Nicomachean Ethics, VII, 2-10, 1145b21-1152a35.

15. l-2ae, q. 77, a. 2.

16. 16. l-2ae, q. 94, a. 4; cf. a. 6 reason may fail to apply the principles of natural law “propter concupiscentiam, vel aliquam aliam passionem”, secondary precepts may fail “propter malas persuasiones ... vel etiam propter pravas consuetudines, et habitus corruptos”. Caesar, though critical of the morals of the Germans, was not quite as hard on them as St, Thomas appears to assume. The full reference is as follows: “latrocinia nullam habet infaraiam quae extra fines cuiusque civitatis fiunt, atque ea iuventutis exercendae ac desidiae minuendae causa fieri praedicant...” (ed. Teubner, Leipzig, 1961, p. 191, VI, 23). On the praise of brigandage or piracy in the Greek: ethnographical tradition cf. J. J. Tierney, The Celtic Ethnography of Posidonius, in Proceedings of the Royal Irish Academy, vol. 60, C, 5, 1960, p. 218 where the present passage is briefly compared with Herodotus and Thucydides.

17. 17. l-2ae, q. 99, a. 2 ad 2. Cf. J. H. Newman, “Liberal Knowledge Its Own End” in Scope and Nature of University Education, Discourse IV, Everyman edition, London, 1915, p. 112—“Quarry the granite rock with razors, or moor the vessel with a thread of silk; then may you hope with such keen and delicate instruments as human knowledge and human reason to contend against those giants, the passion and the pride of man”.

18. 18 l-2ae, q. 94, a. 6.

19. 19. J. Maritain, On the Philosophy of History, London, Blcs, 1959, pp. 82-83. Cf. M. Ginsberg, op. cit., for a discussion of “variations due to differences of moral insight and general level of development, moral and intellectual”.

20. 20. 1, 3, 1094bll-27. Both Aristotle and St. Thomas return to this idea more than once, Cf. II, 2, 1104a2-7; 7,1107a26-35; In l Eth,, lect. 3, (ed. R. M. Spiazzi, no. 32-36); In II Eth., lect. 2 (Spiazzi, n. 259); I.c., lect. 8 (Spiazzi, nn. 333-4).

21. 21. l-2ae, q. 94, a. 4. Cf. J. M. Cameron, The Night Battle, London, Bums and Oates, 1962, p. 93 ff. on “the difficulty about where to place moral discourse on the logician’s chart”.

22. Plato, Republic, I, 331C—“If we had been given weapons by a friend when he was of sound mind, and he went mad and reclaimed them, it would surely be universally 'admitted that it would not be right to give them back. Anyone who did so, and who was prepared to tell the whole truth to a man in that state, would not be just”. A similar moral case is discussed in Xenophon, Memorabilia, IV, c. 2. But a more likely source for the scholastics is Cicero, De officiis, HI, c. 25—“Si gladium quis apud te sana mente deposuerit, repetat insaniens, reddere peccatum sit, officium non reddere. Quid ? Si is, qui apud te pecuniam deposuerit, bellum inferat patriae reddasne deposition ? Non credo: facias enim contra rempublicam, quae debet esse carissima. Sic multa, quae honesta natura videntur esse, temporibus fiunt non honesta; facere promissa, stare , conventis, reddere deposita commutata utilitate fiunt non honesta”.

23. l-2ae, q. 96, a. 6 ad 3—“nullius hominis sapientia tanta est, ut possit omnes singulares casus excogitare ... et si posset legislator omnes casus considerare, non opporteret ut omnes exprimeret propter confusionem vitandam . ..”

24. 2-2ae, q. 57, a. 2ad2;cf. Suppl. 3ae partis, q. 41, a. 1 ad3; De malo, q. 2, a. 4 ad 13.

25. 25. Philosophisches Jahrbuch, 1962 (70), pp. 17-33.

26. The reference given is “St. theol. III Suppl. 41,1, 3; vgl. 2-2, 57, 2,1”. The passage in the Supplementum is, of course, originally found in In IV Sent., d. 26, q. 1, a. 1 and 3.

27. Op. cit., pp. 32-33—“Zweifellos ist dieser Satz im Rahmen der thomistischen Philosophic, ‘un mot S l’aventurc’. Zu seiner Interpretation kdnnte man darauf hinweisen, dass zwar die substantiate Wesensform, die suzammen mit der materia prima das Wesen der Menschen konstituiert, ein von sich aus allgemeines Obergeschichtliches, uberzeitliches und unwandelbares metaphysisches Pritizip ist, dass aber auch ein geschichtliches Wandel der iiberindividueilen, kulturellen und geselfschaf-; tlichen Bedingungen in etwa ein Wandel der menschlichen Natur ist; denn ist ein Wandel der Bedingungen, die zum aktuellen Vollzug des Menschseins im actus secundus notwendig und naturhaft vorausgesetzt sind, da der Mensch von Natur aus animal; sociale und notwendig auf Sprache und Gesellschaft angewiesen ist. Ein solcher geschichtlicher Wandel von ‘status et conditiones hominum’ bringt nach dem zitierten Text auch einen Wandel dessen mit sich, was das Naturrecht vorschreibt. Ob damit cin Ansatz gewonnen ist, von dem her das Problem der Geschichtlichkeit des Naturrecht entfaltet und einer Losung zugefiihrt werden konnte, mag dahingestellt bleiben . .”

28. Patmos, Dusseldorf, 1955, pp. 51-56.

29. 29.Cf, the revised French translation J. Fuchs, Le droit naturel—essai thioloqique, Toumai, Desclle, 1960, p. 54.

30. Ibid., p. 53 note 2. In denying the possibility of natura pura one compromises the gratuitousness of grace. In Humani Generis Pius XII reproved those who held that “God could not create intelligent beings without destining them to a supernatural order and calling them to the Beatific Vision”. H. de Lubac, Surnaturel, Paris, 1946, appears to have held that de potentia absoluta God could have created man in statu naturae purae, but de potentia ordinata He could not do so. On this cf. S. Offelli, “Natura pura" in Enciclopedia Filosopca, Venezia-Roma, 1957, t. III col. 821.

31. Theologia Moralis Generalis, Pars Prima, Roma, University Gregoriana, 1960,pp. 66-88, “De lege naturali in lege Christi”.

32. Op. cit., p. 68—-“Natura intelligitur essentia hominis, turn secundum suum Esse metaphysician (‘animal rationale’, cum omnibus consequents inde necessario fluentibus), tum secundum suum Esse physicum, quo Esse metaphysicum ex voluntate creatoris de facto rcale est, simul cum quibuscumque relationibus accedentibus. Haec natura, ideoque et lex naturalis, inteliguntur fundata in voluntate creatrice Dei, remotiua in eius intellectup et essentia. Natura autem, et correlativa lex moralis, rationi humanae per se impervia non sunt. Natura et correlativa lex moralis distinguuntur ab elementis supernaturalibus, cum correlativa lege morali, quae, saltern ut talia, rationi prorsus imperviae sunt et revelatione necessario indigent.

33. Op. cit., pp. 77-81.

34. Op. cit, p. 77—“Lex naturalis, cum in ipsa essentia hominis personalis radicetur, videri possit esse aliquid plene staticum et non-historicum inde praecise sunt tot obiectiones contra doctrinam legis naturalis. Revera, natura humana historice, quodam sensu, mutabilis est, ut habet S. Thomas; consequenter, et eodem sensu, etiam lex naturalis; quod autem rede intelligendum est.

35. Summa, Suppl., q. 41.a. 1 ad 3; supra note 26.

36. 2-2ae, q. 57, a. 2 ad 1.

37. De malo, q. 2 a. 4 ad 13.

38. l-2ae, q. 97, a. 1; ad 1, ad 3. Cf. S. Gagner, Studien zur Ideengeschichte der Gesetzgebung, Stockholm, Almqvist & Wiksell, 1960, pp. 275-279.

39. J. Fuchs, op. cit., p. 77—“Illud 'Esse hominem’—quidquid accurate sit—objective fundat iudtcium rationis rectae, quinam actus homini conveniant: sive ratione solius ‘esse hominem’, sive ratione huius ‘esse hominem’ in relatione ad naturam realitatum aecidentalium, quae—vel extra vel intra hominem—accedere possunt”.

40. Cf. Pius XI, Quadragesimo Amo, a. 49 (Catholic Truth Society translation):; “History proves that ownership, like other elements in social life, is not absolutely rigid . . .”. J. Messner, Social Ethics, St. Louis-London, Herder, 1949, p. 170, note 28, comments—“To find such evolutionary features of the natural law doctrine . . . given explicit and decided expression in an authoritative ecclesiastical document like the papal encyclical Quadragesima Anno (1931, Pius XI) was a surprise even for many who thought themselves acquainted with the traditional natural law school, not to speak of its opponents, all the more since the Pope deals with a topic always considered fundamental to the doctrine of natural law, nameiy private property”.

41. J. Fuchs, op. cit., pp. 79-81. i:|

42. Op. cit., pp. 81-82—'“Exempli causa, propositio ‘depositum reddendum est’ nor.dum respicit limitationem possibilem iuris; principium ‘non licet alios occidere’ non addit conditiones ‘directe’ et ’propria auctoritate privata’, negligens sic quaestiones poenae capitis, defensionis sui, auctorizationis divinae in materia iuris (cfr, casum Jjikbraham-Isaac); norma ‘non licet auferre invito domino rem alienam’ non indicat ·ipossibilitatem transferendi ins in aliud subiectum iuris, sive ex parte Dei sive per jegitimam auctoritatem”.

43. International Philosophical Quarterly, 1960 (2), pp. 50-80.

44. Op. cit., p. 77—“From now on evolutionary progress will not occur in humans without their awareness, but is initiated and controlled by them. Man is now on the' verge of exercising human dominion over the bio-cultural modifications of human existence. It belongs to man that he complete, in the light of the finalities or evolutionary tendencies of his nature, his imperfect psychological structures, his largely potential principles of action”. He cites Teilhard de Chardin’s saying that we are the players as well as the cards and the stakes in this great game and goes on (p. 78): “While this moral perspective ethos is as yet inchoate in the minds of most people, it does exist in the evolutionary humanists such as Julian Huxley, Herman J. Miller, as well as in Teilhard de Chardin’s Christocentric approach”. Cf. J. C. Flugel, Man, Morals and; Society, Harmondsworth, Peregrine Books, 1962, pp. 316-317.

45. C. Fay, op. cit., p. 61.

46. Ibid., p. 63—“In spite of their unique and changing character, value orientations have universal foci; that is, all humans strive to keep alive as best they know how, to: enjoy association with their fellows, to relate themselves cognitively and affectively to: the universe of being”.

47. 2-2ae, q, 57, a. 2 ad 1.

48. S C. Fay, op. cit., pp. 65-66. Compare P. Lumbreras, De lege, Angelicum, Rome; Studium de Cultura, Madrid, 1953, p. 49—. . etsi evolutionis qul dicuntur philosophi naturaiem legem .... mutabilem praedicent, nobis indubium est naturam humanam ion subdi mutationi, neque propterea legem huius naturae comitem".

49. Ibid., pp. 64-65. Cf. C. Wellman, “The Ethical Implications of Cultural Relativity” in Journal of Philosophy, 1963 (60), pp. 169-184, where it is argued that a human nature relative to culture does not entail ethical relativity. “One may wonder whether the only alternatives are an entirely fixed and an entirely plastic human nature. It might be that enculturation could mould a human being, but only within certain limits. These limits might exist because certain parts of human nature are not at all plastic or because all parts are only moderately plastic. For example it might turn out that the need for food and the tendency to grow in a certain way cannot be modified at all by enculturation, or it might turn out that every element in human nature can be modified in some ways but not in others. In either case what a man becomes would depend partly upon enculturation and partly upon the nature of the organism being encultured ...” (pp. 173-4).

50. Ibid., p. 67. Cf. A. Verdross, Abendlandlsche Rechtsphilosophie, Springer, Wien, 1958, p. 231—“Jeder Mensch besitzt aber nicht nur die ailgemeine Menschennatur, er is immer auch ein konkretes Einzelwesen, das Glied eines bestimmten Volkes in einer: bestimmten Zeit und einer bestimmten Kultur ist. Im Laufe der Geschichte dndern sieh aber nicht nur die VerhSltnisse, sondem auch die Menschen selb est (a footnote refers to Summa theol. 2-2, q. 57, a. 2 ad 1) da uns die Geschichte lehrt, dass primitive Volker allmahlich zu Kulturvolkem haranreifen kfinnen. Daher muss das naturliche Rechtsgesetz, wenn es eine dem Menschen entsprechende Normenordnung ist, auch den Verschiendenbeiten Rechnung tragen, die im Laufe der Geschichte eingetreten sind”.

51. “ De malo, q. 2, a. 4 ad 13; 2-2, q. 57, a. 2 ad 1; Suppl., q. 41, a. 1 ad 3 {—In IV wSent., d. 26, q. 1, a. 1 ad 3). The additional text is In IV Sent., d. 33, q. 1, 2 ad 1— Semper enim et ubique dextera est melior quam sinistra secundum naturam; sed per Saliquod accidens conveniet aliquem esse ambidexterum, quia natuia nostra variabilis est; et similiter etiam est de natural justo, ut ibidem Philosophus dicit”. The reference is of course, to Nicomachean Ethics, V, 7,1134b30-35. For St. Thomas’s commentary on his passage cf. infra.

52. Cf. R. J. Deferrari and M. I. Barry, Complete Index of the Summa Theologica, Washington, Catholic University Press, 1956, pp. 219-220. There are over 4,000 references to “natura” and almost the same number to "naturalis”; not all, it is evident, germane to a discussion of human nature or natural law. L. Schutz, Thomas-lexikon, (Paderbom, 1895, reprint, Stuttgart, 1958, pp. 509-519, gives a systematized account of .'“natura” and “naturalis” in the works of St. Thomas. He classifies the senses of these words rather as Lalande does (cf. supra, note 5).

53. C. 1, n. 2—“Nomen naturae ... videtur significare essentiam rei secundum quod habet ordinem vel ordinationem ad propriam operationem rei, quum nulla res propria ‘ stituatur operatione”

54. In IV Sent., s. 33, qq. 1-2

55. Cf supra note (5); O. Lottin, Le droit naturel chewz saint Thomas d’Aquin et ses predecesseirurs, Bruges, Beyaert, 2nd ed., 1931, p. 76. 55a.III, c. 129.

56. The author of the Supplementum was probably Reginald of Piperno. Cf. M. Grahmann, Die Werke des hl. Thomas von Aquin, Munster, Aschendorff, 1949, 3rd ed., pp. 296-301

57. Suppl 3ae Partis, q. 41, a. 1, ad 3—In IV Sent., d. 26, q. 1, a. 1 ad 3.

58. Nicomachean Ethics, VII, 14, 1154b20; in the Commentary on the Sentences, I.c., the reference is given to the sixth book of the Ethics; in the Supplementum this is silently corrected to the seventh book.

59. In VII Eth., lect. 14 (ed. Spiazzi, nn. 1534-1537). There is still controversy about the date of the Commentary on the Ethics; it is much later than the Commentary on the Sentences, possibly as late as 1271-2. Cf. I. T. Eschmann, Catalogue of St. Thomas’s Works in E. Gilson, Christian Philosophy of St. Thomas Aquinas, London, Gollancz, 1957, p. 405.

60. Nicomachean Ethics, V, 7, 1134bl8-1135aI3; In IV Sent., d. 33, q. 1, a2 ad 1; In V Eth., lect. 12 (ed. Spiazzi, nn. 1016-1034).

61. Ibid., nn. 1026-1028. Both in the Commentary on the Sentences and that on the Ethics St. Thomas allows Aristotle's illustration less than its full force. Aristotle had said that, although the right hand is by nature the stronger “yet it is possible that all men should become ambidextrous”; St. Thomas speaks of some becoming ambidextrous.

62. In IV Sent., d. 33, q, 1, a. 2 ad 1—“Jus naturale semper et ubique, quantum se, habet eamdem potentiam; sed per accidens propter aliquod impedimentum, quandoque et alicubi potest variari, sicut ibidem Philosophus exemplum ponit de rebus naturalibus. Semper enim et ubique dextera est melior quam sinistra secundum naturam; sed per aliquod accidens convenit aliquem esse ambidexterum, quia natura nostra, variabilis est; et similiter etiam est de naturali justo ...”.

63. Cf. Nicomachean Ethics, III, 2, 1112a27. On the triplex cursus rerum in its application to the natural law cf. especially In III Sent., d. 37, q. 1, a. 3.

64. In III Sent., d. 37, q. 1, a. 4 ad 3. The passage may be regarded as a first sketch for the Summa, l-2ae, q. 100, a. 8 ad 3 in which St. Thomas takes a similar view but without saying that God can change nature.

65. De malo, q. 2, a. 4—“Utrum omnis actus sit indifferens”. The chronology of the Quaestiones Disputatae is still very much an open question. It seems, however, fairly certain that the De malo comes between the Prima Pars and the Prima-Secundae of the Summa. Cf. I. T. Eschmann, Catalogue of St. Thomas’s Works, appended to E. Gilson, Christian Philosophy of St. Thomas Aquinas, London, Gollancz, 1957, p. 391; F. Van · Steenberghen, review of O. Lottin, Psychologie et morale aux XII et XIII siecles, t. VI, Revue philosophique de Louvain, 1962 (60), p. 681.

66. De malo, q. 2, a. 4 ad 13—“... alio modo materialiter; et sic non sunt eadem justa et bona ubique et apud omnes; sed oportet ea lege determinari. Et hoc contingit propter mutabilitatem naturae humanae, et diversas conditiones hominum et rerum, secundum diversitatem locorum et temporum; sicut hoc semper est justum quod in emptione et venditione fiat commutatio secundum aequlvalens; sed pro mensura frumenti justum est ut in tali loco vel tempore tantum detur, et in alio loco vel tempore non tantum sed plus vel minus”. Cf. Nicomachean Ethics, V, 7, 1134b34—"The things which are just by virtue of convention and expediency are like measures; for wine and corn measures are not everywhere equal, but larger in wholesale and smaller in retail markets”.

67. 2-2ae, q. 57, a. 2.

68. Ibid. The example of the deposited goods was used by Plato—cf. supra note (22). St. Thomas makes use of it, apart from the present context, in In III Sent., d. 37, a. 1, a. 3; In IV Sent., d. 33, q. , a. 2 ad I; In V Ethicorum, lect. 12 (ed. Spiazzi, n. 1025); l-2ae, q. 94, a. 4; 2-2ae, q. 51, a. 4; 2-2ae, q. 62, a. 5 obj. 1; 2-2ae, q. 120, a. 1. Cf. P. Antoine, “Conscience et loi naturelle” in Etudes, 1963 (317), p. 165—"Ce premier cas de conscience, que l'on peut lire dans la Republique de Platon, ct qui remonte peut-etre a Socrate, sinon plus haut, sera indefiniment rcpris et commente par les moraiistes. Il manifeste que l'on ne peut pas identifier simplement la justice a une formulation juridique”.

69. Thomas de Vio Caietanus, Comm, in 2-2ae, q. 57, a. 2. |

69a. G. M. Manser, Das Naturrecht in thomistischer Beleuchtung, Freiburg in der Schweiz, 1944, p. 60—“Per se sind die Wesenheiten der kreatiirlichen Dinge unveranderiich ... Aber ratione existentiae, kraft der kontingenten Existenz, kann auch die Wesenheit geschbpflicher Dinge, per accidens also, veranderlich genannt werden. So sagt in diesem Sinne prdzis Thomas von Aquin: Das Naturrecht ist immer und uberall, ‘quantum ad se’ unveranderlich dasselbe. Und dennoch kann es ‘per accidens’ ad corruptionem individui’ d.h. infolge seiner existentiellen Unvollkommen- heit ausnahmsweise in diesem oder jenem vordorbenen Individuum infolge der Leidenschaften und der gestbrten normalen Erkenntnis Wandlungen unterworfen sein.” For the phrase about accidental corruption “ad corruptionera individui” Manser refers to De verit., q. 1, a. 5 ad 14; De spir. creat., a. 10 ad 8; la, p. 86, a. 3.

70. H. Rommen, Natural Law, Herder, St. Louis-London, 1947, pp. 166-172. Cf. p. 168—“The divine reason by thinking creates the essence of things. The divine will brings them into existence either immediately as first cause or indirectly through secondary causes. This is basic for the possibility of the natural law, because it means that the essential forms are not dependent in their quiddity on the absolute will of the almighty Spirit, but only in their existence. The essential forms of things are unalterable because they are ideas of the immutable God ...”.

71. J. Funic, Primal des Naturrechtes, St. Gabriel Verlag, Mbdling bei Wien, 1952, p. 92—“Ganz charakteristisch far die Natur ist ihre VerSnderlichkeit. Gnindlage dafur ist vor allem ihre Zusammensetzung aus Akt und Potenz, aus Wirklichkeit und Moglichkeit”.

72. G. M. Manser, Das Naturrecht in thomistischer Beleuchtung, p. 59.

73. ” S. Augustine, De vera religione, c. 31, n. 58—“Conditor legum temporalium ... illam ipsam consulit aetemam, ut secundum eius incommutabiles regulas, quid sit pro tempore iubendum vetandumque discemat”, cited by A. Verdross, Abendlandische Rechtsphilosophie, p. 61; cf. pp. 65-66.

74. Cf. supra note (42).

75. L. Bender, Phllosophia iuris, ed. 2., Officium Libr* Catholici, Rome, 1955, p. 176.

76. Op. cit., pp. 185-6—“Regulae iuris naturalis fundantar in sola natura rerum et nqllo modo fundantur in circumstantiis accidentalibus, in quibus natura individuals vcrsari potest, sed quae etiam abesse possunt”.

77 Ibid. and note 5—“Dicentes ‘non licet ocddere innocentem' exludimus casus, in quibus aliquis occidit violatorem iuris sui titulo exercitii iuris coactivitatis, praesertim pin defensione cruenta, sive privata, sive in bello iusto, aut in applicatione poenae mortis. Sic enim haec verba ab omnibus intelliguntur. Non declarator, solummodo prohibitum esse occidere innocentes, Saepe enim occidere hominem peccatorem erit iniuria et peccatum”.

78. Op. cit., p. 188—-“Ius naturale absolute immutabile praecipit: depositum est reddendum praeterquam in huiusmodi casibus exceptionalibus”.

79. Cf. M. Wittmann, Die Ethik des hi. Thomas son Aquin, Hueber, Mixnchen, 1933, pp. 346-352. >i$