particular piece of land be considered absolutely, it contains no reason why it should belong to one man more than to another, but if it be considered in respect of its adaptability to cultivation, and the unmolested use of the land, it has a certain commensuration to be the property of one and not of another man, as the Philosopher shows.’  Cajetan’s commentary on this article clearly emphasises the distinction between fundamentum and titulus:  ’In the ownership of goods two things are to be discussed.  The first is why one thing should belong to one man and another thing to another.  The second is why this particular field should belong to this man, that field to that man.  With regard to the former inquiry, it may be said that the ownership of things is according to the law of nations, but with regard to the second, it may be said to result from the positive law, because in former times one thing was appropriated by one man and another thing by another.’  It must not be supposed, however, from what we have just said, that there are no natural titles to property.  Labour, for instance, is a title flowing from the natural law, as also is occupancy, and in certain circumstances, prescription.  All that is meant by the distinction between fundamentum and titulus is that, whereas it can be clearly demonstrated by natural law that the goods of the earth, which are given by God for the benefit of the whole of mankind, cannot be made use of to their full advantage unless they are made the subject of private ownership, particular goods cannot be demonstrated to be the lawful property of this or that person unless some human act has intervened.  This human act need not necessarily be an act of agreement; it may equally be an act of some other kind—­for instance, a decree of the law-giver, or the exercise of labour upon one’s own goods.  In the latter case, the additional value of the goods becomes the lawful property of the person who has exerted the labour.  Aquinas therefore pronounced unmistakably in favour of the legitimacy of private property, and in doing so was in full agreement with the Fathers of the Church.  He was followed without hesitation by all the later theologians, and it is abundantly evident from their writings that the right of private property was the keystone of their whole economic system.[2]

[Footnote 1:  II. ii. 57, 3.]

[Footnote 2:  A community of goods, more or less complete, and a denial of the rights of private property was part of the teaching of many sects which were condemned as heretical—­for instance, the Albigenses, the Vaudois, the Begards, the Apostoli, and the Fratricelli. (See Brants, Op. cit., Appendix II.)]