[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.]

AEgidius Romanus closely follows the teaching of his master on the subject of slavery.  ’What does AEgidius do?  He unites Aristotle and St. Augustine against human liberty.  He declares with the latter that man has lost the right of belonging to himself, since he has fallen from the primitive order established by God Himself in nature.  He admits with Aristotle the existence of two races of men, the one designed for liberty, the other for servitude....  This is not all—­to this servitude which he calls natural, the author joins another, purely legal, but which does not seem to him less just, namely, that which is founded on the right of war, and which obliges the conquered to become the slaves of the conquerors—­to give up their liberty in exchange for their lives.  Our author admits it is just in itself, because in his opinion it is useful to the defence of one’s country; it excites warriors to courage by placing before their eyes the terrible consequences of cowardice.’[1] The teachings of St. Thomas and AEgidius were accepted by all the later scholastics.[2] Biel, whose opinion is always very valuable as being that of the last of a long line, says that there are three kinds of slaves—­slaves of God, of sin, and of man.  The first kind of slavery is wholly good, the second wholly bad, while the third, though not instituted by, is approved by the jus gentium.  He proceeds to state the four ways in which a man may become enslaved:  namely, ex necessitate, or by being born of a slave mother; ex bello, by being captured in war; ex delicto, or by sentence of the law in the case of certain crimes committed by freedmen; and ex propria voluntate, or by the sale of a man of himself into slavery.[3]

[Footnote 1:  Franck, op. cit., p. 90.]

[Footnote 2:  Franck, op. cit., p. 91.]

[Footnote 3:  Biel, Inventarium seu Repertorium generale super qualuor libros Sententiarum, iv. xv.  I; and see Carletus, Summa Angelica, q. ccxii.]