First Question: On the Essence of Natural Law

St. Thomas, I-II, q. 91, a. 2 and q. 94, a. 1.

245. Thesis. The participation of eternal law in the rational creature is true law. - For it is:

1. an ordination of reason: the rational creature participates in law intellectually and rationally, and therefore the participation of eternal law in it is properly called law, because it is something of reason: a dictate constituted by reason; in other creatures it is not participated rationally, whence in them a proper inclination is not called law except by similitude;

2. promulgated by God to a community: for although promulgation is made in individuals, by the impression of reason, nevertheless it is made by reason not indeed as it is particular, but as it is common and the same in all, proceeding from the author of nature;

3. it is made for moral honesty, not of one person, but of the whole of humanity.

1. "The common voice of the whole of nature, or rather of its author, who, although He speaks to individuals, speaks as a public person, because He speaks as author of nature itself." Suarez, De Legibus, l. I, c. II, n. 4.

246. Essence of natural law. - Natural law is not law insofar as it is in the legislator as in the one regulating, and accordingly it is not eternal law itself; but it is law as it is in subjects as in those regulated, and accordingly it is the participation, manifestation, passive promulgation of eternal law in us.

And indeed:

1. It is not the will of God, whether necessary or free: for actions are not good or evil because they are commanded or prohibited by the willing God, but they are commanded or prohibited as intrinsically good or evil in themselves; and indeed good things which are required as necessary by order cannot fail to be commanded, and evil things cannot fail to be prohibited. Whence, if per impossible God did not will natural law, nevertheless it would become known to us and obligate us in the same way, because human nature would be constituted in the same way by commanding divine reason, and it, as also our acts, would be ordered to the ultimate end. Law, namely, essentially is an ordination of reason, not of will.

2. The Nominalists, such as Ockham, Pierre d'Ailly, Gerson; likewise Descartes and Pufendorf, say: the free will of God. Suarez speaks in the same way. Liberatore, De Bie, and Gutberlet say: necessary will; Meyer: hypothetically necessary will. Cathrein says: will, without further determination.

3. Billuart notes, diss. 1, a. 1: "For law it suffices that it be directive of human actions, and that it have the power of obligating. But eternal law (as to necessary precepts) and natural law have these two independently of every act of will. Concerning the first there is no doubt; concerning the second it is also clear, because, by the very fact that the reason of the divine mind dictates and intimates that God is to be worshiped, parents are to be honored, etc., and that theft, lying, etc. are evil and therefore to be avoided, there arises in man an obligation to do those things in their time and to avoid these things, even if, per impossible, there were no will obligating to these, because from their intrinsic things or from their nature they are either to be done or to be avoided, by the very fact that through the dictate of reason they are intimated as such."

2. Nor does the will or power of God necessarily seem to have to be attended to in order that natural law become known. For moral necessity or obligation is the absolute necessity of a means to an absolutely necessary end (Q. D. De Veritate 17, a. 3), so that the means is necessary not only under the condition, if someone wills the end, but absolutely, because the end also is absolutely necessary and altogether imposed upon us. Whence, in order to know law or obligation, it suffices that there be present the absolute necessity of an end which is altogether imposed, and that the necessary connection of means to the end be known, and consequently the obligation to those means. Now the end is imposed upon us by the physical necessity of nature: the highest good of rational nature and highest happiness, so that we cannot fail to will it; and reason a) can know that certain particular goods fitting to rational nature pertain to that end (as a necessary condition of true perfection and ultimate happiness), while certain others do not pertain to it, and b) thus can perceive the necessary connection of certain acts, as means, with that end. Therefore the absolute moral necessity of means and obligation arising from nature, or natural law, can be known while abstracting from God, namely, without attending to the will or authority of God. This nevertheless does not exclude that natural law remotely and ultimately depends upon God, and that obligation, once God is known, is perceived more fully and perfectly.

1. Thus Vasquez, Gerdil, D'Hulst, Mercier (in an autograph course of moral philosophy); Manuel de philosophie neo-scolastique (of the Louvain school); Gillet, Du Fondement intellectuel de la Morale d'apres Aristote; Lottin, Le Probleme des Fins en morale, p. 164; Loi Naturelle et positive, p. 20; L'Ordre moral et l'ordre logique, p. 331; Du Rousseaux, Philosophie morale, p. 200 and 227; Garrigou-Lagrange, Dieu, p. 309; Fonsegrive in Revue de Philosophie, 1910; Vie diocesaine, 1923, p. 383; Collectanea Mechliniensia, 1928, p. 330.

3. Yet it is not the categorical imperative of autonomous reason or will (Kant and the Rationalists). For autonomy cannot be reconciled with the idea of true obligation, because human reason cannot obligate itself. Whence obligation is not constituted by human reason, but is imposed from the necessary inclination of our nature, which cannot be changed by us and which always persists immutable. Furthermore, this opinion rests upon the false foundation that man is an end to himself, or an end in himself (cf. Syllabus, prop. 3 and 50), while nevertheless he is essentially a creature of God, depending upon Him and ordered to Him. The ultimate end, namely, is not constituted by reason but by the author of nature.

Therefore, considered in first act, natural law is the habitual inclination of rational nature to its own acts, namely, to knowing and desiring the end or perfect good, and the means necessarily leading to it, or honorable acts to be chosen; whence nature truly is a law to itself, in this sense, that from the necessary and ineluctable inclination of nature to the end there arises obligation to employ the means. In other words, natural law is the light of natural reason by which we are able to discern what is good to be done or evil to be avoided; this light shows goodness and malice and is the rule of our acts, insofar as it is derived from the divine light and is an impression of the divine light in us. Considered in second act, law is the actual dictate or judgment of reason prescribing in a general mode what is good to be done, what evil is to be avoided. Hence:

a) although natural law is not a habit, since it is not that by which reason acts, but that which it dictates, nevertheless the precepts of the law of nature are not always actually considered by reason, and then they are in it habitually, and thus natural law can be called a habit, because it is held by habit;

b) it differs from synderesis, which is not the innate light of reason or its actual dictate, but is a habit (or facility, not strictly innate but flowing spontaneously from the intellect) by which we easily enunciate not all but the first moral principles; whence it contains these principles virtually;

c) it differs from conscience, which is not a general norm of acting but a judgment concerning things to be done in particular.

247. Foundation of natural law. - One must ask not only about the essence, but also about the foundation of natural law or natural obligation, and consequently of every obligation; for positive obligation is founded upon the obligation of natural law, insofar as this commands that superiors are to be obeyed.

Now from what has been said it is clear:

1. That the sole, sufficient, or ultimate foundation is not the will of God, whether free or necessary: not free, because the question is of necessary law; not necessary, because it depends upon something prior from which it has necessity, namely, upon divine wisdom and essence (Q. D. De Veritate 23, a. 6); and therefore it is not the ultimate, sole, and sufficient foundation. Adversaries indeed say that no law is given without a legislator, and that no precept can be conceived without the will and authority of one prescribing. But:

a) this is true of positive law, which is not necessary, not of natural law, whose obligation arises from the nature of things and from the necessary tendency of our nature to the end;

b) besides, by saying that natural law is obligatory because reason dictates that the will of God prescribing is to be obeyed, they will with difficulty free themselves from contradiction, because the said principle, as prescribed by reason alone, is known as obligatory and does not ultimately depend on knowledge of the will of God; otherwise there would be a vicious circle;

c) finally, the first principles of natural law, for example, good is to be done, etc., are known before knowledge of God, just as the knowledge itself of the terms of which they consist and by which, once known, they are immediately enunciated, precedes this knowledge. Whence, although God in the ontological order is the necessary foundation of natural law, He is not so in the logical order of knowledge.

1. Cf. I-II, q. 94, a. 2 and 4; q. 58, a. 5; II-II, q. 47, a. 6; Q. D. De Veritate 16, a. 1 and 2.

2. Nor is the foundation human reason alone, because just as an effect depends more upon the first cause than upon the second cause, so obligation depends more upon the author of nature and eternal law than upon nature and human reason participated from God: for the essential order of things is not from reason nor from itself, but is derived from eternal law.

The foundation seems to be distinguished as twofold:

a) One secondary and proximate: human nature itself regarded completely with its essential and necessary relations, or its ultimate end absolutely imposed upon it, or the essential order of things according to which certain things have a necessary connection with the ultimate end; and this is sufficient for conceiving true and properly so-called natural obligation, as we have said.

b) The other primary, remote, and ultimate: the intellect of God itself, or eternal law with its root, the divine essence. For eternal law is the fountain of human nature and reason, and this is not the rule of our acts except from divine reason, of which it is also a participation. In the same way the foundation of the principles of speculative reason and of eternal truths is twofold: namely, the proximate foundation, the nature of things and the relations which hold among them (which suffices for conceiving necessary truths), and the ultimate foundation, which is the essence and intellect of God. And just as we are able to know the truth of the first principles of speculative reason from the proximate foundation alone, the nature of things, without knowing their ultimate foundation, the divine intellect, so we are able to know the truth and obligation of the first principles of practical reason without knowing their ultimate foundation: the divine intellect and eternal law.

248. Corollary: the system of secular morality, or, as they say, of obligation independent of God, must therefore be refuted, by saying that it is:

1. Here we consider the system under the respect of obligation; above we spoke of it under the respect of morality itself, n. 134.

a) essentially incomplete, since it is silent about God the true ultimate end and about our duties toward God;

b) false, insofar as it affirms natural law to be founded in nature or reason alone, eternal law of God being excluded;

c) ineffective, because law lacks sufficient sanction, and accordingly, the propensities of men to vices being considered, in fact they will not sufficiently observe it.

Yet it does not seem that it should be called contradictory, as if it were impossible to conceive natural law while abstracting from God the legislator, or obligation without God willing and commanding: for that is to say too much, and does not seem true.

But if it is said that obligation cannot be conceived unless the ultimate end to be attained is known, regarded in the concrete, which is God, we think this necessary only for complete knowledge of the whole moral law. For partial knowledge, knowledge of the end considered in the abstract suffices, insofar as it is the supreme and complete good of rational nature. But even granting this, God would not yet have to be regarded as supreme legislator or as commanding by will, but only as the Supreme Good to be pursued.

249. Observation. - Therefore eternal law and natural law differ:

1. subjectively: the former is in God, the latter in the created mind; and therefore

2. materially in physical being: the former is divine wisdom (and essence), the latter is the created light of reason participated from it; and consequently

3. in knowability: the former in itself is known by God alone and by the blessed, the latter is perceived by the light of reason.

But they agree: 1) formally and in the notion of dictate, because the rectitude and obligation of both is the same, since one is a participation of the other; and therefore:

2. objectively, because they dictate the same things, not indeed a) totally according to the whole extension, for eternal law also extends to irrational creatures and to those things which God commands by positive law (or ordains to be commanded by others); but b) partially: for although not everything which eternal law commands is commanded by natural law, nevertheless everything which the law of nature commands is also commanded by eternal law. Therefore they are the same law, just as the image of the seal and of the sealed thing is the same; yet the seal is more extended than the sealed thing.