The first thing upon which the mediæval teachers insist is that value is not determined by the intrinsic excellence of the thing itself, because, if it were, a fly would be more valuable than a pearl, as being intrinsically more excellent.[1] Nor is the value to be measured by the mere utility of the object for satisfying the material needs of man, for in that case, corn should be worth more than precious stones.[2] The value of an object is to be measured by its capacity for satisfying men's wants. 'Valor rerum aestimatur secundum humanam indigentiam.... Dicendum est quod indigentia humana est mensura naturalis commutabilium; quod probatur sic: bonitas sive valor rei attenditur ex fine propter quem exhibetur: unde commentator secundo Metaphysicae _nihil est bonum nisi propter causas finales_; sed finis naturalis ad quem justitia commutativa ordinet exteriora commutabilia est supplementum indigentiae humanae...; igitur supplementum indigentiae humanae est vera mensura commutabilium. Sed supplementum videtur mensurari per indigentiam; majoris enim valoris est supplementum quod majorem supplet indigentiam.... Item hoc probatur signo, quia videmus quod illo tempore quo vina deficiunt quia magis indigeremus eis ipsa fiunt cariora....[3] [Footnote 1: 'In justitia commutativa non estimatur pretium commutabilium secundum naturalem valorem ipsorum, sic enim musca plus valeret quam totus aurum mundi' (Buridan, _op. cit._, v. 14).] [Footnote 2: Slater, 'Value in Theology and Political Economy,' _Irish Ecclesiastical Record_, Sept. 1901.] [Footnote 3: Buridan, _op. cit._, v. 14 and 16. Antoninus of Florence says that value is determined by three factors, _virtuositas_, _raritas_, and _placibilitas_ (_Summa_, ii. 1, 16.)]