Pojęcie „ius gentium” w „Summa Theologiae” św. Tomasza z Akwinu

The subject of the considerations in presented paper is the concept of ius gentium in two selected fragments of St. Thomas Aquinas: S.Th. I-II, q. 95, a. 4 and S.Th. II-II, q. 57, a. 3. The introduction to their detailed analysis is the discussion of three issues necessary for the correct interpretation of Aquinas’ argu-ments, i.e. the concept of ius gentium in the first book of the Justinian Digest, the definition of ius gentium in the Etymologies of St. Isidore of Seville and an explanation of the relationship between the concepts of ius and lex in the Summa Theologica. The conducted research allows to conclude that the Angelic Doctor uses the concept of ius gentium in a twofold sense. The first of them is of a juridical nature and can be equated with the understanding of this term on the basis of the sources of Roman law. Ius gentium is therefore a set of legal norms common to all peoples, which enable, first of all, mutual economic turnover, although to some extent also apply to the external activity of the state. The second meaning of the term ius gentium, although also to some extent inspired by the sources of Roman law, has a broader character and a deeper philosophical foundation. On the basis of the treaty on justice, ius gentium constitutes the social order of functioning of all people based on natural reason (naturalis ratio).