In handling these issues, St. Thomas bases himself on an analogy predicated upon human government. Thomas observes that those things that man does, and over which he has control, are subject to human law. But matters that relate to his intrinsic nature--for example that he should have soul, or hands, or feet--are not subject to human law. It is apparent that no ruler could decree a change in the fundamental nature of man. Though a law may be fashioned that will force a man to board a plane, no law will ever give man natural wings. While a man may be sentenced to death by hanging under human law, there is no ukase that can effect that man shall no longer have a body. There are some things that are simply outside of the scope of man’s legislative competence.
By analogical reasoning, then, Aquinas concludes that the Eternal Law governs all things created by God whether "contingent or necessary." This means that not only man, who by God's design is a creature that is to be governed by reason, but all creation operates under the Eternal Law. This includes the irrational creatures--stars, planets, rocks, trees, and animals--though they participate in the Eternal Law in a manner less noble than man (since they do not enjoy the reason or freedom that man does). ST IaIIae, Q.93, art.5, resp.
In this regard, St. Thomas observes, human laws operate in a manner differently than the Eternal Law. Human law only extends to humans, and cannot be said to operate or bind irrational creation. Even though the irrational creature is subject to man’s control and dominion, human law requires a subject upon which the law may be imprinted and which recognizes a rule of action. Though a ruler is able to issue laws that bind his subjects in this manner, he is unable to do so for the irrational creation that may be found in his domain. Irrational creation cannot be controlled by man by law, though it be controlled by him through technology. ST IaIIae, Q.93, art.5, resp.
This limitation in man’s law, is not to be found with God. As Creator, God imprints upon all of his creation the principles of their proper action, and so all of creation is subject to Eternal Law. The Divine Reason and Will are substantially different than man’s reason and will, and so God is able to extend His Eternal Law across the whole of creation and imprint itself among both rational and irrational creation alike. ST IaIIae, Q.93, art.5, ad.1, 2. “And thus all actions and movements of the whole of nature are subject to eternal law.” IaIIae, Q.93, art.5, resp. Though there is no part of the created world that can claim independence from God’s Eternal Law, the manner in which the that Law applies to rational creatures is distinct from the way it applies to irrational creation:
[I]rrational creatures are subject to the eternal law, through being moved by Divine providence; but not as rational creatures are, through understanding of the Divine commandment.IaIIae, Q.93, art.5, resp.
Since man has a dual nature—participating in the rational world, but sharing animal functions with brute animals—he participates in the Eternal Law in two ways. The first way of participation is through understanding, that is through his knowledge of the Eternal Law. As we explained in prior posts, this knowledge would be obtained through Revelation or through the application of his reason to the expression of God’s law found in the created order. The second way that man participates in the Eternal Law is through a natural inclination toward that which would be consonant with the Eternal Law. ST IaIIae, Q.93, art. 6, resp. Man's sensitity to the Eternal Law (particularly as it finds promulgation in him through the Natural Law) is thus both one of Reason and one of inclination. It is not a Law of pure Reason, such as one advanced by René Descartes or Immanuel Kant. Nor is it a Law of pure Instict or Impulse, such as may have been advanced by David Hume. The Eternal Law manifests itself in man in the fullness of his created nature, that is as a being that is soul and body incarnate.
Even the wicked cannot escape from being subject to God’s law, though they disobey it. In the wicked, the knowledge of the Eternal Law can be darkened by bad habits and disordered passion, and the natural inclination towards the Law can be vitiated by vice. These can exercise such an influence over the mind and natural inclinations that they can be virtually destroyed. On the other hand, both knowledge and inclination can be developed by the good through knowledge of faith and wisdom, the development of virtuous habits, and, above all, God's Grace. ST IaIIae, Q.93, art. 6, resp. There will be varying degrees of subjection to the Eternal Law, the good being more nearly subject to the Eternal Law compared to the wicked, who are subject to the Eternal Law in an imperfect manner, and whose subjection shows itself more along the lines of suffering punishment or an interior disorder or lack of harmony, perhaps to show itself in neurotic behaviors. The wicked can never claim absolute emancipation from the Eternal Law, for to do so he would effectively have to destroy his entire nature; accordingly, even in the most evil, there will always remain some inclination toward the Eternal Law of God. ST IaIIae, Q.93, art.6, ad. 2. Indeed, even the damned, in their unhappy state, are under the Eternal Law. ST IaIIae, Q.93, art.6, ad. 3. "If I ascend to heaven, You are there; If I make my bed in Sheol, behold, You are there." Si ascendero in caelum tu illic es, se descendero ad infernum ades. (Ps. 138:8) What to the good is a comfort (God's abiding presence and rule), to the wicked must seem oppressive.
The Christian remains under the Eternal Law of God, though in a manner of speaking he may be said to be out from under the Law, as St. Paul says in his letter to the Galatians. See Gal. 5:18. According to St. Thomas, what St. Paul meant in writing so to the Galatians is that the Christian will not obey the Law because of fear, and he will not view it as a burden or imposition on his will or a loss of his freedom; rather, the Christian will ideally fulfill the law in willing joy, encouraged by the love of God in his heart, and the promptings of the Holy Spirit. ST IaIIae, Q.93, art. 6, ad. 1. In this manner, he may be said to be released from the Eternal Law because he lives the life of God. In fact, to the extent the Christian does the work of the Holy Spirit, he may be said to have acted outside the Eternal Law, because the Holy Spirit, being God, is not subject to the Eternal Law of God. Hence: “Where the Spirit of the Lord is, there is liberty.” 2 Cor. 3:17. The liberty of the Christian is not one from theonomianism to antinomianism; it is one from theonomianism supernomianism. It is not leaving the Law to a state of lawlessness; it is leaving the Law to be above it.
Though all creation—rational and irrational—is subject to the Eternal Law, it is different with God. Just as man cannot legislate regarding his own nature, so things that pertain to God's Nature, such as God's Will and His Essence, are not subject to the Eternal Law. And indeed, this follows from the fact that God is the Eternal Law itself. ST IaIIae, Q. 93, art.4, resp. Thus, St. Thomas rejects the notion that God's Will is subject to Eternal Law. "[S]ince God's will is His very Essence, it is subject neither to the Divine government, nor to the eternal law, but is the same thing as the eternal law." ST IaIIae, Q.93, art.4, ad.1.
St. Thomas also addresses the relationship between the promulgation of the Eternal Law by God the Father and the Divine Word, that is, God the Son. Since God the Son shares in God’s nature, it follows that He is not subject to the Eternal Law, but is the same thing as the Eternal Law. ST IaIIae, Q.93, art.2, ad. 1, 2. St. Thomas argues that since the Word expresses all things that are in the Father's knowledge, "the eternal law itself is expressed" by the Word of God, not, however as a "Personal name in God," but by appropriation to the Son because the relationship (convenientiam) between "type and word," the ratio and verbum. ST IaIIae, Q.93, art.2, ad.2; see also Q. 93, art.4, ad.2. Jesus, who is the Word of God Incarnate, would not be subject to Eternal Law in his divinity, but in his humanity, he would be "subject to the Father by reason of His human nature," and therefore would be governed by the Eternal Law. ST, IaIIae, Q. 93, art.4, ad.2. Because the Word of God expresses the Eternal Law, it may justly be said that Jesus, the Word of God made flesh, expresses for us the Eternal Law in His divinity, and, in His humanity, He expresses for us complete fidelity to the Eternal Law. In Christ we have both the Eternal Law and obedience to the Eternal Law made manifest for us.
Similarly, the Holy Spirit, sharing as He does in God's Nature, is not subject to the Eternal Law. ST, IaIIae, Q.93, art.6, ad.1.
In his book An Elegant and Learned Discourse of the Light of Nature (1652), Nathanael Culverwell calls the Eternal Law "the spring and original of all Lawes ... that fountain of Law, out of which you may see the Law of Nature bubbling and flowing forth to the sons of men." (Culverwell, 35). This English divine is on good ground, for he relied upon the Dominican St. Thomas Aquinas's Summa Theologica for his guidance: "For as Aquinas does very well tell us, the Law of Nature is nothing but participatio Legis aeternae in Rationali creatura, the copying out of the eternal Law, and the imprinting of it upon the breast of a Rational being, that eternal Law was in a manner incarnated in the Law of Nature." Culverwell, 35.
The Natural Law is an expression, a particularization, a "copying out" of the Eternal Law in the rational creature that is man. Because of this intimate relationship, it follows that, now that we have focused on the Eternal Law, the Lex Aeterna, we may approach the Natural Law as it has been summarized by St. Thomas Aquinas in his Summa Theologica.