He is one of the four most important Christian philosopher-theologians of Western Europe in the High Middle Ages, together with Thomas Aquinas, Bonaventure and William of Ockham.

Duns Scotus also developed a complex argument for the existence of God, and argued for the Immaculate Conception of Mary.

[11] Duns Scotus's age is based on the first certain date for his life, that of his ordination to the priesthood at St Andrew's, Northampton, England, on 17 March 1291.

[14] According to tradition, Duns Scotus was educated at a Franciscan studium generale (a medieval university), a house behind St Ebbe's Church, Oxford, in a triangular area enclosed by Pennyfarthing Street and running from St Aldate's to the castle, the bailey and the old wall,[15] where the Friars Minor had moved when the University of Paris was dispersed in 1229–30.

[16] Duns Scotus appears to have been in Oxford by 1300, as he is listed among a group of friars for whom the provincial superior of the English ecclesiastical province (which included Scotland) requested faculties from the Bishop of Lincoln for the hearing of confessions.

Later in that academic year, however, he was expelled from the University of Paris for siding with Pope Boniface VIII in his feud with King Philip IV of France over the taxation of church property.

He was relaxing or talking with students in the Prato clericorum or Pré-aux-Clercs – an open area of the Rive Gauche used by scholars for recreation – when orders arrived from the Franciscan Minister General; Scotus left immediately, taking few or no personal belongings.

The story about Duns Scotus being buried alive, in the absence of his servant who alone knew of his susceptibility to coma, is probably a myth.

[25] For example, Book II Distinction 2, about the location of angels, is a starting point for a complex discussion about continuous motion, and whether the same thing can be in two different places at the same time (bilocation).

Scotus wrote purely philosophical and logical works at an early stage of his career, consisting of commentaries on Aristotle's Organon.

These are the Questions on Porphyry's Isagoge and Aristotle's Categories, Peri hermeneias, and De sophisticis elenchis, probably dating to around 1295.

[26] His commentary on Aristotle's Metaphysics was probably written in stages, the first version having started around 1297,[24] with significant additions and amendments possibly after the completion of the main body of the Ordinatio.

There were already concerns about this within two centuries of his death, when the 16th-century logician Jacobus Naveros noted inconsistencies between these texts and his commentary on the Sentences, leading him to doubt whether he had written any logical works at all.

[29] The Questions on the Prior Analytics (In Librum Priorum Analyticorum Aristotelis Quaestiones) were also discovered to be mistakenly attributed.

[citation needed] In 1922, Grabmann showed that the logical work De modis significandi was actually by Thomas of Erfurt, a 14th-century logician of the modist school.

Thus the claim that Martin Heidegger wrote his habilitation thesis on Scotus[30] is only half true, as the second part is actually based on the work by Erfurt.

Like other realist philosophers of the period (such as Aquinas and Henry of Ghent) Scotus recognised the need for an intermediate distinction that was not merely conceptual but not fully real or mind-dependent either.

Scotus argued for a formal distinction (distinctio formalis a parte rei), which holds between entities which are inseparable and indistinct in reality but whose definitions are not identical.

Under the first heading of Relative Properties, Scotus argues for a triple primacy of efficiency, finality and pre-eminence.

Citing Anselm of Canterbury's principle, "potuit, decuit, ergo fecit" (He [i.e., God] could do it, it was appropriate, therefore He did it), Duns Scotus devised the following argument: Mary was in need of redemption like all other human beings, but through the merits of Jesus' crucifixion, given in advance, she was conceived without the stain of original sin.

[47] This apparently careful statement provoked a storm of opposition at Paris, and suggested the line 'fired France for Mary without spot' in the famous poem "Duns Scotus's Oxford," by Gerard Manley Hopkins.

Duns Scotus was long honored as a Blessed by the Order of Friars Minor, as well as in the Archdioceses of Edinburgh and Cologne.

[49] He was declared Venerable by Pope John Paul II in 1991, who officially recognized his liturgical cult, effectively beatifying him on 20 March 1993.

[50] Owing to Scotus's early and unexpected death, he left behind a large body of work in an unfinished or unedited condition.

In a letter to Thomas Cromwell about his visit to Oxford in 1535, Richard Layton described how he saw the court of New College full of pages from Scotus's work, "the wind blowing them into every corner.

"[52] John Leland described the Oxford Greyfriar's library in 1538 (just prior to its dissolution) as an accumulation of "cobwebs, moths and bookworms.

For one thing, Scotus has received interest from secular philosophers such as Peter King, Gyula Klima, Paul Vincent Spade, and others.

This line of argument first emerged in the 1960s among popular French philosophers who, in passing, singled out Duns Scotus as the figure whose theory of univocal being changed an earlier approach which Aquinas had shared with his predecessors.

In recent years, this criticism of Scotus has become disseminated in particular through the writings of the 'Radical Orthodox' group of theologians, drawing on John Milbank and Catherine Pickstock.

The Radical Orthodox model has been questioned by Daniel Horan[58] and Thomas Williams,[59] both of whom claim that Scotus's doctrine of the univocity of being is a semantic, rather than an ontological theory.