Treatise on Law

Treatise on Law is Thomas Aquinas' major work of legal philosophy. It forms questions 90–108 of the Prima Secundæ ("First [Part] of the Second [Part]") of the Summa Theologiæ, Aquinas' masterwork of Scholastic philosophical theology. Along with Aristotelianism, it forms the basis for the legal theory of Catholic canon law. Aquinas defines a law as "an ordinance of reason for the common good, made by him who has care of the community, and promulgated." Law is an ordinance of reason because it must be reasonable or based in reason and not merely in the will of the legislator. It is for the common good because the end or telos of law is the good of the community it binds, and not merely the good of the lawmaker or a special interest group. It is made by the proper authority who has "care of the community", and not arbitrarily imposed by outsiders. It is promulgated so that the law can be known. He says: Thus from the four preceding articles [of Question 90], the definition of law may be gathered; and it is nothing else than an ordinance of reason for the common good, made by him who has care of the community, and promulgated. Strictly speaking, this is a definition of human law. The term "law" as used by Aquinas is equivocal, meaning that the primary meaning of law is "human law", but other, analogous concepts are expressed with the same term. The Treatise on Law deals with Aquinas view’s on the objective ethical aspect of human decision-making. Aquinas presents a question and then puts each question into article raising specific questions he has. The first three questions are broken down in four topics concerning the essence of law, the effects of law, and the eternal law. The first question (Question 90 of the larger Summa) is on the essence of law. Aquinas breaks the question down into four articles. The first article is on law's relation to reason. Aquinas believes that reason is the first thing human acts upon; “the source in any kind of thing is the measure and rule of that kind of thing...