The Problem of Natural Law 
by Douglas?Kries
Lexington, 214 pages, $25.95
The decade after the Second World War witnessed a small boom of interest in traditional natural-law thinking. The devastation and moral atrocities of the war, the rebuilding of European legal systems, the emergence of declarations and covenants of human rights, and the expansion of communist regimes across Europe and Asia made the subject of natural law appear attractive.
Recovering premodern understandings of natural justice, however, proved tricky. The ancient understanding of natural right, and its more complex descendant of natural law, could hardly be unwrapped from historical desuetude and used right out of the box.
Among those who warned about the philosophical difficulties was the European émigré Yves R. Simon, at the University of Chicago. A notable figure in the neoscholastic revival, Simon gave a series of lectures on natural law in 1958, later published under the title The Tradition of Natural Law: A Philosopher’s Reflections . He insisted that the subject of natural law “is difficult because it is engaged in an overwhelming diversity of doctrinal contexts and of historical accidents. It is doubtful that this double diversity, doctrinal and historical, can so be mastered as to make possible a completely orderly exposition of the subject of natural law.”
While acknowledging the existence of modern crises in law, politics, and culture, Simon worried that natural law would be recovered not as a philosophy but rather as an ideology. “Against such powers of destruction we feel the need for an ideology of natural law. The current interest in this subject certainly expresses an aspiration of our society at a time when the foundations of common life and of just relations are subjected to radical threats. No matter how sound these aspirations may be, they are quite likely to distort philosophic treatments.”
It is precisely on this point that we can turn to Douglas Kries’ Problem of Natural Law . Like Simon, he is suspicious of hopes, however well intentioned, that natural law can be a kind of Aaron’s rod that swallows the snakes of discord.
But Kries brings the philosophical problems of natural law into focus by investigating Thomas Aquinas’ understanding of conscience, particularly lumen synderesis , the light of conscience, according to which the human intellect is said to possess an indefectible habit of the first principles of action.
Kries’ thesis is that Thomas makes natural law depend on a premise that is difficult to verify and, anyway, proves unnecessary for articulating a robust understanding of natural law. In his book’s final chapters, he argues that, once synderesis is abandoned, natural law can be more easily defended against its modern critics.
Kries gives a useful exposition of the historical evolution of the term synderesis . New Testament usage is chiefly associated with Paul, particularly his dictum in his letter to the Romans about the gentiles whose conscience bears witness to a law written in their hearts. How synderesis eventually became a term of art in the medieval schools is a long story. It was Jerome, in his Commentary on Ezekiel , who spoke of synderesis as a spark of conscience “which was not extinguished even in the breast of Cain after he was ejected from paradise.”
These scriptural and patristic dicta caused considerable perplexity as they arrived on the doorstep of the medieval schoolmen. Synderesis did not fit neatly into the new science drawn from Aristotle. In standard Aristotelian terms, it would have to be a power, a habit, a law, or an action. For his part, Thomas concluded that synderesis is not a power (intellect) or an act of the power (conscience) or the norm of action (natural law) but rather an innate, habitual disposition to grasp the first principles of the natural law.
This was a deft interpretation, allowing Thomas to avoid conflating innate habits with innate knowledge. Like the other medieval masters, Thomas knew that, for Aristotle, the intellect does not naturally know anything without experience of extramental reality, beginning in the senses. Seeing that he couldn’t front-load knowledge of moral principles ahead of experience, he hit on the solution of positing a habit. He concluded that synderesis is an indefectible habit, of the agent intellect, that renders the knower habitually poised to understand that the “good is to be done and pursued and evil resisted.”
This could be only the beginning of moral knowledge and action. Discerning and judging action in light of the natural law need to be perfected and stabilized by the cardinal virtues (acquired habits) and infused virtues (faith, hope, and charity). Synderesis pertains to only one part of that complex dynamism. Nonetheless, it is an important part. One might say that the doctrine of synderesis yields the benefit of universal principles, universally known without relying on the disputable notion of innate ideas.
Kries claims, rightly, I think, that Thomas attributes to the natural intellect a kind of “brightness” in its first stirrings. Moreover, his teaching on the soul is scandalously democratic, for the knowledge of first principles does not immediately depend on either the influx of increate light or the educational conventions of the city. At least with respect to the first principles of action, every person is not only capacitated but also habitually inclined to render judgment according to those principles. Kries contends that “Thomas altered, intentionally or unintentionally, Aristotle’s position on the universal knowledge of morality among mankind and . . . thereby weakened the case for classical ethical thought.” Where Aristotle admitted a capacity to make sound judgments according to nature, Thomas introduces a habitual inclination to do so. The good and the bad alike share the same epistemic starting point.
What’s not to like about the position that we naturally know the common principles without an immediate reliance on supernatural light or the character-forming discipline of the city? Kries notes that Thomas changed Aristotle’s teachings. But he belabors this point, which is his least interesting. All the medieval masters engaged in more than minor tweaks of Aristotle, and one could hardly study medieval philosophy with profit if that were one’s complaint.
Kries gives at least two other criticisms, which are more penetrating. First, the “brightness” of synderesis could encourage the rationalism that comes from a creeping innatism. If certain universal principles are known to all, it is tempting to expand the repertoire to meet whatever issues are in contest. This is fertile soil for what Yves Simon meant by ideology: confusing what would be good for people to know with what they actually know. Second, it runs up against the stubborn fact that we achieve, at best, a paltry and precarious consensus about morals. If we survey contemporary opinion about natural rights, we see that the opinions are diverse and constantly changing.
Add it all up, Kries claims, and the Thomist position burdens the philosophy of natural law. So what is the better solution? Kries argues that Thomas’ theory of natural law can be maintained more or less intact without the doctrine of synderesis . Natural law suggests that there are at least some fixed standards, but we needn’t believe that a subset of these standards are grasped at the outset by everyone. “Human beings,” he observes, “do not seem to think that the fact that few people understand Einstein’s theory of relativity tells against the truth of that theory, but they do seem to think that the fact that few people understand classical natural right does tell against its truth.” We should bracket synderesis and then see what happens in the discourse among philosophers who have a stake in the idea of natural right or natural justice.
What are we to make of this? It is always fair to bracket a component of a systematic philosophy to see what happens. In this case, the bracketing is proposed to evaluate how much of Thomas’ natural law remains intact after moving him closer to Aristotle’s understanding of natural right. I doubt, however, that Kries has adequately set up the problem.
For one thing, Kries overestimates precisely what kind of knowledge Thomas has in mind when he speaks of a habitual knowledge of first principles of action. He attributes to Thomas the position that “natural morality is naturally known to all.” Perhaps some Thomists go that far, but not Thomas, who understood that a habitual grasp of first principles hardly constitutes a morality. The agent needs the facts drawn from experience and inquiry; conclusions need to be framed in the manner of adequate propositions; and conclusions need to be applied to facts.
Moreover, all of these need the institutions of moral training. Someone who knows only the first principles is not someone to whom you would give the keys to your car, much less someone who can reliably access what constitues the moral life. We might have other reasons to question Thomas’ understanding of the lumen synderesis , but the notion that it guarantees a natural morality that is naturally known to all is not one of them.
Here and there, but especially in his chapter on John Calvin, Kries alights on this point. He notes that “Thomas himself does not succumb to this temptation to restrict morality to what can be obtained by the vulgar” and that “Thomas himself clearly saw that there would be limits to natural law’s ability to effect consensus.” Before revising Thomas, we need to sort out more thoroughly why he did not believe a universal knowledge of first principles necessarily causes a universal knowledge of morality any more than a knowledge of the principle of noncontradiction necessarily causes an actual knowledge of the various sciences.
In fact, there is another option, which was typical not only of medieval but also of some modern natural-law doctrines. We know first principles by the influx of divine light. If we are to judge lower things according to a higher norm, and if the changeable human intellect is not that norm, we need an increate light that instills and causes knowledge of moral norms. In Thomas’ time, this was the default position, shared variously by Platonists, Augustinians, and Aristotelians who held that there is only one agent intellect that does the knowing.
Kries does not pay enough attention to this situation, which is the original site of what he dubs “the problem.” Thomas was not radical because he believed that some universal principles are known by the soul but rather because he insisted that the proximate cause is a created light in the creature, that it is a habit rather than a completely assembled knowledge. The whole point of the lumen synderesis stands or falls right here. Hence the definition of natural law as participation in the eternal law rather than a direct illumination of that law. This was not a popular position then, and it isn’t now. It stood against both the notion of innate ideas as well as the common idea that a divine light imparts the principles regardless of the habits and labors of the human mind. Thomas’ understanding of an innate habit steered the middle course between innatisms (natural and supernatural) and the position that the educational regime of the city is the midwife of moral knowledge.
At the end of the book, I waited to see how Kries, having bracketed synderesis , would maintain a robust philosophy of natural law without succumbing to one of the two extreme positions. One way or the other, a price will be paid for the bracketing, and Kries does not seem to know that he must pay it. Even so, The Problem of Natural Law takes us close to the heart of the problem. Anyone interested in something more than slogans about natural law will want to read the book.
Russell Hittinger is the William K. Warren Professor of Catholic Studies at the University of Tulsa.
