Updating the Mystery Quotation Contest. The Angelic Doctor rules.
“It is proper to justice, as compared with the other virtues, to direct man in his relations with others … on the other hand the other virtues perfect man only in those matters which befit him in relation to himself.” This text from the Summa Theologica [II, 57, 1] has the very same meaning as the textbook adage “lustitia est ad alterum:” Justice is directed toward the other man. The difference, the separateness of the other party is intended more precisely and literally than may appear at first glance.
What distinguishes justice from love is just this: in the relationship of justice, men confront each other as separate “others,” almost as strangers. “Justice properly speaking demands a distinction of parties.” Because father and child are not entirely separate individuals, because the child, instead, belongs to the father, and the father feels toward the child almost as he feels toward himself, “so between them there is not a simpliciter iustum, the just, simply,” not justice in the strict sense. Because the loved one is not properly “someone else,” there is no formal justice between those who love each other. To be just means to recognize the other as other. It means to give acknowledgment even where one cannot love. –- Pieper, Josef. 1954. The Four Cardinal Virtues. New York: Harcourt Brace: 54.