In his work Introduction to Moral Theology, Fr. Romanus Cessario O.P. remarked on certain misconceptions with respect to how the natural had grown in application and importance over time in the late 19th and early 20th centuries: arguing that the presentation of the natural law given in teaching manuals was anachronistic and unhelpful, and in extreme cases was at times influenced by Suarezian or casuist trends in moral theology.
The casuistry embedded in the Roman Catholic manual tradition greatly contributed to misinterpretations of natural law. Although Prummer follows Aquinas’ own material distinctions, this sort of presentation nonetheless reinforces the misconception that Catholic moral theology is given to consider every specific moral issue as if natural law alone supplied the ultimate determination. The manualist misconstrues of natural law also explain the tendency among some contemporary authors to think that natural law theory supplies the equivalent of a complete moral theory… Natural law is not the only resource needed for a complete theory of Christian morality. A realist moral theologian recognizes that natural law provides a starting point for discovering the concrete forms of moral goodness.Romanus Cessario, Introduction to Moral Theology
Natural Law and Justice
If a scholar of Aquinas were to look at what the Angelic Doctor wrote on the natural law in the Summa Theologiae, they would be surprised to find very little actually discussed by St. Thomas. Fewer than twenty questions in the Prima Secundæ are devoted to questions specifically concerning law and only one of them to the natural law. By contrast, what Aquinas had to say on the virtues, more specifically the virtue of justice, greatly eclipses what he wrote on law. Questions 57-122 are all devoted to discussing the importance and concrete application of justice, and the entirety of the Secunda Secundæ discusses the virtues in general.
Aquinas, in discussing the natural law, outlines the precepts of the law in the Summa, arguing that the precepts of natural law are roughly equivalent to first principles in speculative sciences and demonstration. They provide us the starting point, as it were, for praxis and practical reasoning:
[T]he precepts of the natural law are to the practical reason, what the first principles of demonstrations are to the speculative reason; because both are self-evident principles… Since, however, good has the nature of an end, and evil, the nature of a contrary, hence it is that all those things to which man has a natural inclination, are naturally apprehended by reason as being good, and consequently as objects of pursuit, and their contraries as evil, and objects of avoidance. Wherefore according to the order of natural inclinations, is the order of the precepts of the natural law. Because in man there is first of all an inclination to good in accordance with the nature which he has in common with all substances: inasmuch as every substance seeks the preservation of its own being, according to its nature: and by reason of this inclination, whatever is a means of preserving human life, and of warding off its obstacles, belongs to the natural law. Secondly, there is in man an inclination to things that pertain to him more specially, according to that nature which he has in common with other animals: and in virtue of this inclination, those things are said to belong to the natural law, “which nature has taught to all animals” [Pandect. Just. I, tit. i], such as sexual intercourse, education of offspring and so forth. Thirdly, there is in man an inclination to good, according to the nature of his reason, which nature is proper to him: thus, man has a natural inclination to know the truth about God, and to live in society: and in this respect, whatever pertains to this inclination belongs to the natural law; for instance, to shun ignorance, to avoid offending those among whom one has to live, and other such things regarding the above inclination.In Summa Theologiae Ia-IIae qu. 94 art. 1
A problem one might face with Aquinas’ theory is that the natural law, or more specifically its precepts, do not determine their own application. A sentiment as universal as “striving towards living in a society and avoiding offense against those with whom one has to live” might be admirable, but it can hardly help determine for us the day-to-day demands of justice—especially living in an increasingly technocratic and hyper-communicative world. These principles may indeed be what ought to form the basis of our practical reasoning, but they are not principles which determine their own application. Aquinas is aware that this is the case, and in discussing justice as it pertains to the virtue of epieikeia (reasonable accommodation of circumstances in pursuit of equity), writes how justice is that with which laws are concerned, and principally deal.
When we were treating of laws, since human actions, with which laws are concerned, are composed of contingent singulars and are innumerable in their diversity, it was not possible to lay down rules of law that would apply to every single case. Legislators in framing laws attend to what commonly happens: although if the law be applied to certain cases, it will frustrate the equality of justice and be injurious to the common good, which the law has in view.In Summa Theologiae IIa-IIae qu. 120 art. 1
Relationality of Justice
Interestingly enough, Aquinas, in treating the virtue of justice, notes how it is more principally the virtue pertaining to the virtuous person as it especially stands in importance among the different virtues. Speaking of the subjective qualities of the soul, it simply is better on account of its residing in reason, but also because it is precisely through justice that we can be good towards other people, rather than being good in ourselves.
If we speak of legal justice, it is evident that it stands foremost among all the moral virtues, for as much as the common good transcends the individual good of one person. On this sense the Philosopher declares (Ethic. v, 1) that “the most excellent of the virtues would seem to be justice, and more glorious than either the evening or the morning star.” But, even if we speak of particular justice, it excels the other moral virtues for two reasons. The first reason may be taken from the subject, because justice is in the more excellent part of the soul, viz. the rational appetite or will, whereas the other moral virtues are in the sensitive appetite, whereunto appertain the passions which are the matter of the other moral virtues. The second reason is taken from the object, because the other virtues are commendable in respect of the sole good of the virtuous person himself, whereas justice is praiseworthy in respect of the virtuous person being well disposed towards another, so that justice is somewhat the good of another person, as stated in Ethic. v, 1. Hence the Philosopher says (Rhet. i, 9): “The greatest virtues must needs be those which are most profitable to other persons, because virtue is a faculty of doing good to others. For this reason, the greatest honors are accorded the brave and the just, since bravery is useful to others in warfare, and justice is useful to others both in warfare and in time of peace.”In Summa Theologiae IIa-IIae qu. 58 art. 12
Justice then seems to be just as important—if not even more so—than the precepts of the natural law, because it is only through justice that right relations between different members of a given society can obtain. Not only relations with family members, or friends, but lawgivers, employers, statesmen, and the like all require the application of justice.
Understanding Justice in our Contemporary Context
Putting aside justice as conventionally understood by Aquinas in his 13th century medieval context, what would he have to say with regards to the application of social media and communication-based technology that we have encountered and utilized in the 21st century? Is justice something that concerns us insofar as we employ social media? Do we have some sort of obligation towards justice in how we interact with each other socially online? My question then for us all for Wednesday is; what is the relationship between the natural law, or more specifically the precepts of the natural law and the virtue of justice, and what does it mean then to be justice today given the widespread use of social media and technology?
Philosophical Happy Hour
Come join us for drinks (adult or otherwise) and a meaningful conversation. Open to the public! Held every Wednesday from 5:45–7:15pm ET.
 Cessario, R. (2001). Introduction to Moral Theology. : Catholic University of America Press. Pg. 104
 In Summa Theologiae Ia-IIae qu. 94 art. 1 Second and Revised Edition, 1920, Literally translated by Fathers of the English Dominican Province, Online Edition Copyright © 2017 by Kevin Knight https://www.newadvent.org/summa/2094.htm#article1
 In Summa Theologiae IIa-IIae qu. 58 art. 12 https://www.newadvent.org/summa/3058.htm#article12