His philosophical position was determined, or at least very greatly influenced, by the antagonism between the Dominicans and the Franciscans. Further, while the genius of Aquinas was constructive, that of Duns Scotus was destructive; Aquinas was a philosopher, Duns a critic. The latter has been said to stand to the former in the relation of Kant to Leibnitz. In the matter of Universals, Duns was more of a realist and less of an eclectic than Aquinas. Theologically, the Thomistic system approximates to pantheism, while that of Scotus inclines distinctly to Pelagianism. The doctrine of the Immaculate Conception was the great subject in dispute between the two parties; it was strenuously opposed by Aquinas, and supported by Duns Scotus, although not without reserve. There were, however, differences of a wider and deeper kind. In opposition to Aquinas, who maintained that reason and revelation were two independent sources of knowledge, Duns Scotus held that there was no true knowledge of anything knowable apart from theology as based upon revelation. In conformity with this principle he denied that the existence of God was capable of being proved, or that the nature of God was capable of being comprehended. He therefore rejected as worthless the ontological proof offered by Aquinas. Another chief point of difference with Aquinas was in regard to the freedom of the will, which Duns Scotus maintained absolutely. He reconciled free-will and necessity by representing the divine decree not as temporarily antecedent, but as immediately related to the action of the created will. He maintained, in opposition to Aquinas, that the will was independent of the understanding, that only will could affect will. From this difference as to the nature of free-will followed by necessary consequence a difference with the Thomists as to the operation of divine grace. In ethics the distinction he drew between natural and theological virtues is common to him with the rest of the schoolmen. (Cf. AQUINAS.) Duns Scotus strongly upheld the authority of the church, making it the ultimate authority on which that of Scripture depends. (See also SCHOLASTICISM.)
The most important of his works consisted of questions and commentaries on the writings of Aristotle, and on the _Sentences_ of Lombard, the so-called _Opus Oxoniense_ or _Anglicanum_. Complete works, edited by Luke Wadding (13 vols., Lyons, 1639) and at Paris (26 vols., 1891-1895). There is an edition of his _De modis significandi_ or _Grammatica speculativa_, the first attempt to investigate the general laws of language, by F.M. Fernández García (Quaracchi, Florence, 1902).