'Thus,' according to Janet, 'St. Thomas admits slavery as far as one can admit it, and for all the reasons for which one can admit it. He admits with Aristotle that there is a natural slavery; with St. Augustine that slavery is the result of sin; with the jurisconsult that slavery is the result of war and convention.'[1] 'The author justifies slavery,' says Franck, 'in the name of St. Augustine, and in that of Aristotle; in the name of the latter by showing that there are two races of men, one born to command, and the other to obey; in the name of the former in affirming that slavery had its origin in original sin; that by sin man has forfeited his right to liberty. Further, we must admit slavery as an institution not only of nature and one of the consequences of the fall, we must admit a third principle of slavery which appears to St. Thomas as legitimate as the other two. War is necessary; therefore it is just; and if it is just we must accept its consequences. One of these consequences is the absolute right of the conqueror over the life, person, and goods of the conquered.'[2] [Footnote 1: _Op. cit._, vol. i. p. 431.] [Footnote 2: Franck, _op cit_., p. 69.] Aquinas returns to the question of slavery in another passage, which is interesting as showing that he continued to make use of the analogy between slavery and property which we have seen in the Fathers. 'A thing is said to belong to the natural law in two ways. First, because nature inclines thereto, _e.g._ that one should not do harm to another. Secondly, because nature did not bring in the contrary; thus we might say that for man to be naked is of the natural law because nature did not give him clothes, but art invented them. In this sense the possession of all things in common and universal freedom is said to be of the natural law, because, to wit, the distinction of possession and slavery were not brought in by nature, but devised by human reason for the benefit of human life. Accordingly, the law of nature was not changed in this respect, but by addition.'[1] [Footnote 1: I. ii. 94, 5, ad. 3.]