John Duns Scotus: Life, Philosophy, and the Legacy of the Subtle Doctor

First published Thu May 31, 2001; substantive revision Fri Oct 11, 2019

John Duns Scotus (1265/66–1308), often hailed as the “Subtle Doctor,” stands as a towering figure among the philosopher-theologians of the High Middle Ages. His profoundly intricate and nuanced philosophical system has indelibly shaped discussions across a remarkably diverse range of subjects. From the intricacies of religious language semantics and the complexities of the problem of universals to the illuminating nature of divine knowledge and the very essence of human freedom, Scotus’s intellectual contributions remain profoundly relevant and continue to inspire scholarly debate and exploration. This article will delve into the known details of John Duns Scotus’s life and the chronology of his works. Furthermore, it will provide a comprehensive overview of some of his most pivotal positions within the core domains of philosophy, encompassing natural theology, metaphysics, epistemology, ethics, and moral psychology.

1. Life and Works of John Duns Scotus

1.1 The Life of John Duns the Scot

The name ‘Scotus’ itself serves as a clear identifier, denoting John Duns Scotus’s Scottish origin. His family name was Duns, coinciding with the name of his birthplace, a village in Scotland situated near the English border. While the precise date of John Duns Scotus’s birth remains unknown, historical records confirm his ordination to the priesthood within the Franciscan Order at Saint Andrew’s Priory in Northampton, England, on March 17, 1291. The canonical minimum age for ordination at the time was twenty-five, establishing that John Duns Scotus was born before March 17, 1266. Speculation suggests he was ordained at the earliest permissible age, placing his birth between December 23, 1265, and March 17, 1266, based on Bishop of Lincoln ordinations records.

John Duns Scotus embarked on his academic journey in philosophy and theology at Oxford University in the 1280s. By the academic year 1298–99, he was lecturing on the first two books of Peter Lombard’s Sentences. Around 1302, John Duns Scotus moved to Paris, continuing his Sentences lectures (likely in the order of Book I, Book IV, Book II, Book III). A significant disruption occurred in June 1303 when John Duns Scotus, along with eighty other friars, was expelled from France due to their allegiance to Pope Boniface VIII in his conflict with King Philip IV of France. Following Boniface’s death in October 1303, the king permitted the exiled scholars to return, allowing John Duns Scotus to resume his lectures in late 1303. He achieved the title of Doctor of Theology in 1305 and served as Franciscan regent master in Paris during 1306–07. In 1307, John Duns Scotus was transferred to the Franciscan studium in Cologne, commencing his duties as lector in October. He passed away in Cologne in 1308, with November 8 traditionally recognized as his death date.

1.2 Scotus’s Works: A Legacy of Scholarly Output

Scholars generally agree that John Duns Scotus’s earliest writings comprise commentaries on the Old Logic, including questions on Porphyry’s Isagoge and Aristotle’s Categories, two sets of questions on Peri hermeneias, and De sophisticis elenchis. These works are estimated to date from around 1295, with the Quaestiones super De anima also considered an early piece, potentially from the late 1280s or early 1290s. John Duns Scotus’s other Aristotelian commentary, the Quaestiones super libros Metaphysicorum Aristotelis, appears to have been initiated early in his career, although Books VI through IX are deemed later works or later revisions. Furthermore, John Duns Scotus authored an Expositio on Aristotle’s Metaphysics, which was rediscovered and edited by Giorgio Pini after centuries of being unidentified.

The study of John Duns Scotus’s commentaries on Peter Lombard’s four books of Sentences presents considerable complexity. John Duns Scotus lectured on the Sentences multiple times, revising his material extensively over time. The Lectura represents John Duns Scotus’s Oxford lectures on Books I and II of the Sentences from 1298–99. The Ordinatio, a version prepared by John Duns Scotus for publication, draws from the Lectura and his Paris lectures. The Ordinatio, which John Duns Scotus continued to revise until his death, is considered his magnum opus, with its critical edition completed in 2013. John Duns Scotus also lectured on the Sentences in Paris, resulting in various Reportationes of these lectures, with a critical edition currently in progress. While the Paris lectures were chronologically later than those in Oxford, parts of the Ordinatio, particularly Book IV and possibly Book III, are believed to be later than corresponding sections of the Reportatio.

In addition to these major works, John Duns Scotus produced 46 short disputations titled Collationes, dating from 1300–1305, a later work in natural theology known as De primo principio, and Quaestiones Quodlibetales from his time as regent master in 1306–07. Finally, the Theoremata, while its authenticity has been questioned, is now largely accepted as a genuine work of John Duns Scotus based on recent critical editions.

2. Natural Theology of John Duns Scotus

2.1 Methodological Preliminaries in Scotus’s Natural Theology

Natural theology, in essence, endeavors to establish the existence and nature of God through arguments independent of any purported revelation. John Duns Scotus firmly believed in the possibility of human beings attaining knowledge of God through reason alone. Aligned with Aristotelian principles, John Duns Scotus posited that all human knowledge originates from sensory experience. However, he maintained confidence in the capacity of human intellect to ascend from these empirical foundations to an understanding of God.

Like Thomas Aquinas, John Duns Scotus affirmed that our knowledge of God begins with the observation of creatures. Consequently, proofs for God’s existence and nature must be quia arguments (reasoning from effect to cause), rather than propter quid arguments (reasoning from essence to characteristic). Both Aquinas and John Duns Scotus concurred that the essence of God remains unknowable to humans in this earthly life. A key distinction between them lies in their views on predication. John Duns Scotus argued for univocal predication, asserting that certain predicates can be applied to both God and creatures with precisely the same meaning. Aquinas, conversely, advocated for analogical predication, where words applied to God have meanings related to but distinct from their meanings when applied to creatures.

John Duns Scotus presented several compelling arguments for univocal predication and against analogy (Ordinatio 1, d. 3, pars 1, q. 1–2, nn. 26–55). One notable argument leverages Aquinas’s own framework. Aquinas stated that all our concepts originate from creatures. John Duns Scotus countered, “Where then does the analogous concept originate?” If all concepts derive from creatures, concepts applied to God must also originate from creatures. They cannot merely be similar concepts, as in analogy, but must be identical concepts, as in univocity. These are the only concepts accessible to human understanding. Therefore, rejecting concepts derived from creatures would preclude any meaningful discourse about God, a conclusion John Duns Scotus deemed untenable.

Another argument for univocal predication draws upon Anselm’s ontological argument. Anselm proposed examining all predicates, discarding those that are purely relational as they do not express a thing’s intrinsic nature. For any predicate F, either:

(a) It is in every respect better to be F than not to be F. ~or~ (b) It is in some respect better to be not-F than F.

Predicates falling into category (b) imply limitation or deficiency. Anselm argued that all predicates in category (a) must be predicated of God, while those in category (b) cannot (except perhaps metaphorically). John Duns Scotus concurred with Anselm (and Aquinas, SCG I.30) on this. John Duns Scotus termed qualities that are always better to possess “pure perfections” (perfectiones simpliciter), defining them as predicates that do not imply limitation.

John Duns Scotus asserted that pure perfections can be univocally predicated of God. He argued that Anselm’s test necessitates univocity. To apply Anselm’s test, we must first grasp a concept, such as ‘goodness’. We then assess if it is always better to be good than not-good. Recognizing that it is, we predicate ‘good’ of God. This test is only valid if the concept of ‘goodness’ remains consistent in both applications.

The necessity of univocity becomes clearer when considering alternative viewpoints. One might argue that the concept of a pure perfection applies only to creatures, necessitating a different concept for God. Conversely, one could argue that the concept applies solely to God, requiring a different concept for creatures. The first option, suggesting a pure perfection applicable to creatures but not God, contradicts the idea of God as the most perfect being. The second option, restricting pure perfection to God, implies that perfections in creatures are not truly perfections, undermining the very basis for identifying pure perfections through creaturely examples. The process of identifying pure perfections begins by observing perfections in creatures – features that enhance creatures in every respect. Thus, we cannot determine God’s features and then deduce pure perfections; rather, we identify pure perfections and then understand God’s features.

Beyond univocal concepts, John Duns Scotus believed we can attain a proper (distinctive) concept of God. While we cannot fully grasp God’s essence in this life, we can know God through general concepts shared with creatures. However, in another sense, a proper concept of God is attainable – one applicable only to God. By elevating any pure perfection to its highest degree, it becomes uniquely predicable of God. A more comprehensive description of God can be achieved by combining all pure perfections at their highest degrees.

However, these composite concepts, such as “highest good” or “first cause,” combine disparate notions. John Duns Scotus proposed a simpler, uniquely divine concept: “infinite being.” While seemingly composite, “infinite being” describes an essentially unified entity – a being whose very existence is intrinsically unlimited. The concept of infinite being holds a central role in John Duns Scotus’s natural theology, particularly in his proof for God’s existence.

2.2 Scotus’s Proof of the Existence of God: The Argument from First Cause

John Duns Scotus’s argument for God’s existence is widely recognized as a seminal contribution to natural theology, renowned for its complexity and depth. It involves multiple sub-arguments supporting each key conclusion. A brief overview is provided here, noting that variations of the proof appear in Lectura 1, d. 2, q. 1, nn. 38–135; Ordinatio 1, d. 2, q. 1, nn. 39–190; Reportatio 1, d. 2, q. 1; and De primo principio.

John Duns Scotus begins by establishing the existence of a first agent, a being that is first in efficient causality. He distinguishes between essentially ordered and accidentally ordered causes. In an accidentally ordered series, a member’s causal activity is independent of its being caused. For instance, grandparent A begets parent B, who begets child C. B’s ability to beget C is not contingent on A’s existence or causal activity. In contrast, in an essentially ordered series, later members’ causal activity depends on prior members. For example, shoulders move arms, which move a golf club. The arms’ ability to move the club is dependent on the shoulders’ movement.

With this distinction, John Duns Scotus presents his argument for a first efficient cause:

(1)	No effect can produce itself.
(2)	No effect can be produced by just nothing at all.
(3)	A circle of causes is impossible.
(4)	Therefore, an effect must be produced by something else. (from 1, 2, and 3)
(5)	There is no infinite regress in an essentially ordered series of causes.

(5a)	It is not necessarily the case that a being possessing a causal power C possesses C in an imperfect way.
(5b)	Therefore, it is possible that C is possessed without imperfection by some item.
(5c)	If it is not possible for any item to possess C without dependence on some prior item, then it is not possible that there is any item that possesses C without imperfection (since dependence is a kind of imperfection).
(5d)	Therefore, it is possible that some item possesses C without dependence on some prior item. (from 5b and 5c by modus tollens)
(5e)	Any item possessing C without dependence on some prior item is a first agent (i.e., an agent that is not subsequent to any prior causes in an essentially ordered series).
(5f)	Therefore, it is possible that something is a first agent. (from 5d and 5e)
(5g)	If it is possible that something is a first agent, something is a first agent. (For, by definition, if there were no first agent, there would be no cause that could bring it about, so it would not in fact be possible for there to be a first agent.)
(5h)	Therefore, something is a first agent (i.e., an agent that is not subsequent to any prior causes in an essentially ordered series—Scotus still has to prove that there is an agent that is not subsequent to any prior causes in an accidentally ordered series either. That’s what he does in step (6) below). (from 5f and 5g)

(6)	It is not possible for there to be an accidentally ordered series of causes unless there is an essentially ordered series.

(6a)	In an accidentally ordered series, each member of the series (except the first, if there is a first) comes into existence as a result of the causal activity of a prior member of the series.
(6b)	That causal activity is exercised in virtue of a certain form.
(6c)	Therefore, each member of the series depends on that form for its causal activity.
(6d)	The form is not itself a member of the series.
(6e)	Therefore, the accidentally ordered series is essentially dependent on a higher-order cause.

(7)	Therefore, there is a first agent. (from 4, 5, and 6)

Building upon this, John Duns Scotus proceeds to argue for the existence of an ultimate goal of activity (first in final causality) and a maximally excellent being (first in “pre-eminence”). He establishes the “triple primacy”: a being that is first in efficient causality, final causality, and pre-eminence. John Duns Scotus then demonstrates the coextensivity of these primacies, meaning a being first in one is also first in the others. He further argues that such a being possesses intellect and will, and is necessarily infinite. Finally, John Duns Scotus concludes that only one such being can exist.

2.3 Divine Infinity and the Doctrine of Univocity in Scotus

Divine infinity holds a central position in John Duns Scotus’s natural theology, akin to divine simplicity in Aquinas’s system. It serves as a foundational attribute from which other divine characteristics are derived. However, unlike simplicity in Aquinas, which complicates theological semantics, infinity in John Duns Scotus both informs our best concept of God and underpins the validity of theological language. For John Duns Scotus, ontology and theological semantics are mutually reinforcing. The doctrine of univocity rests on the premise that the difference between God and creatures, in terms of pure perfections, is ultimately one of degree (Cross [1999], 39). As previously noted, John Duns Scotus’s argument for univocity emphasizes that ascribing pure perfections to God entails attributing the same perfections found in creatures, albeit infinitely in God and limitedly in creatures. This establishes a harmonious relationship between ontology (God’s being) and semantics (how we speak of God).

John Duns Scotus critiques Aquinas’s argument for divine infinity, which posits that a form limited by matter is finite, and God, being simple, is not limited by matter, therefore God is infinite. John Duns Scotus points out the fallacy of denying the antecedent in this argument. Furthermore, he argues that simplicity alone does not entail infinity. “If an entity is finite or infinite, it is so not by reason of something accidental to itself, but because it has its own intrinsic degree of finite or infinite perfection” (Ordinatio 1, d. 1, pars 1, q. 1–2, n. 142). Simplicity does not automatically lead to infinity, as finitude is not a consequence of composition. Aquinas’s conception of infinity is negative and relational, defining the infinite as that which is not bounded by something else. John Duns Scotus proposes a positive conception of infinity as an intrinsic property, an “intrinsic degree of perfection,” not merely the absence of limitation.

This positive conception of infinity is derived from our understanding of “the potentially infinite in quantity.” Aristotle argued against actual quantitative infinity, acknowledging only potential infinity through successive parts. John Duns Scotus asks us to imagine all parts of a quantitative infinity existing simultaneously – an actual quantitative infinity. He then shifts to qualitative infinity, envisioning a quality like goodness existing infinitely, with no possibility of further addition. Infinite goodness is not composed of finite “goodness-bits” but is an intrinsic, non-quantitative feature. Infinite being is analogous, described by John Duns Scotus as “a measure of intrinsic excellence that is not finite.” This makes “infinite being” the simplest concept for understanding God, as infinity is an intrinsic mode of being, not an accidental attribute. Concepts like ‘infinite goodness’ and ‘infinite power’ are equally simple. John Duns Scotus emphasizes “infinite being” as it “virtually contains” all other infinite perfections of God, allowing for deduction of other perfections from it, making it the most theoretically fruitful concept of God accessible in this life.

3. Metaphysics in the Scotist System

3.1 The Subject Matter of Metaphysics According to John Duns Scotus

Metaphysics, according to John Duns Scotus, is a “real theoretical science.” It is “real” because it deals with actual entities rather than mere concepts; “theoretical” because its pursuit is for knowledge itself, not practical application; and a “science” because it proceeds deductively from self-evident principles. Sciences are differentiated by their subject matter, and John Duns Scotus dedicates considerable effort to defining metaphysics’ unique subject matter. He concludes that metaphysics is concerned with “being qua being” (ens inquantum ens), studying being in its fundamental essence, rather than focusing on specific types of being, like material being.

The scope of “being qua being” encompasses the study of transcendentals. Transcendentals are concepts that transcend the division of being into finite and infinite, and the further categorization of finite being into Aristotle’s ten categories. “Being” itself is transcendental, along with its “proper attributes”: “one,” “true,” and “good,” which are coextensive with being. John Duns Scotus also identifies disjunctions coextensive with being as transcendentals, such as “infinite-or-finite” and “necessary-or-contingent.” Furthermore, all pure perfections are transcendentals, as they transcend the finite/infinite distinction. However, pure perfections are not coextensive with being; while God and humans can be wise, earthworms, though beings, are not wise.

The Aristotelian categories also fall under metaphysics when studied as beings, not merely as logical concepts. John Duns Scotus affirms the existence of ten categories, with substance being primary. Substances are beings in the fullest sense, possessing independent existence and not existing in another entity. The other nine categories – accidents – exist within substances. These accidents are quantity, quality, relation, action, passion, place, time, position, and state (habitus).

3.2 Matter and Form, Body and Soul in Scotist Metaphysics

Consider an individual substance, such as oneself. The change from pallor to tan illustrates a key characteristic of substances: they can undergo changes in accidents while retaining numerical identity. This is accidental change, where a substance persists, acquiring different accidents. However, substantial change is different. Coming into existence is not accidental change, as there is no pre-existing substance persisting through the change. Substantial change is the very coming-into-being of a substance. Yet, something must persist even through substantial change to allow for change itself, preventing substances from arising from and disappearing into nothingness. Following Aristotle, John Duns Scotus identifies matter as what persists through substantial change and substantial form as what determines a specific parcel of matter as a unique, individual substance. Accidental forms account for a substance’s accidental qualities.

While initially adhering to Aristotelian orthodoxy, John Duns Scotus diverges in three significant ways regarding matter and form: he argues that matter can exist without form, not all created substances are form-matter composites, and a substance can have multiple substantial forms.

Firstly, John Duns Scotus posits that God can create “prime matter,” matter devoid of any form. Matter and form are distinct, as evidenced by substantial change where matter persists while forms change. While this separability might only imply matter’s existence apart from a given form, John Duns Scotus extends it further. Divine omnipotence allows God to directly cause what is usually caused through secondary causes. God typically creates matter through form, but divine omnipotence negates this necessity. God can create matter independently of form. Furthermore, as matter is distinct from form, God creates matter directly and can conserve it directly, independent of any forms.

Secondly, John Duns Scotus rejects “universal hylomorphism,” the view that all created substances are form-matter composites (Lectura 2, d. 12, q. un., n. 55). Universal hylomorphism was prevalent among Franciscans before John Duns Scotus. Bonaventure, for example, argued that even angels, though spiritual, must be form-matter composites. Matter represents potentiality, form actuality. Purely immaterial angels would be pure actuality, which Bonaventure reserved for God alone. John Duns Scotus, however, rejects the unqualified equation of matter with potentiality and form with actuality. Prime matter, though formless, can be actual, and immaterial beings are not necessarily devoid of potentiality.

Thirdly, John Duns Scotus defends the plurality of substantial forms in some substances (Ordinatio 4, d. 11, q. 3, n. 54), a Franciscan doctrine contested by others. A substantial form defines a parcel of matter as a specific, unique, individual substance. If the soul were the sole substantial form of a human being, as Aquinas and others believed, then upon death, when the soul departs, the remaining matter would not constitute the same body. It would be a new substance with new accidents, as the defining substantial form would be absent.

To avoid these implications, John Duns Scotus and many Franciscans proposed multiple substantial forms. A “form of the body” (forma corporeitatis) makes matter a distinct organism, while the “animating form” or soul endows it with life. At death, the soul ceases to animate, but the body remains numerically the same, organized by the form of the body, though it eventually decomposes due to the weakness of this form alone.

John Duns Scotus’s view is even more nuanced, considering each organ of a living body as a substance (matter-form composite). Whether he also recognized a forma corporeitatis beyond organ forms is debated (Ward 2014, 90–93). Without it, a corpse would not be the same body as the living organism. However, accidents inhering in organs could persist after death, as organs, being substances, could continue to exist for a time even after the organism ceases to exist.

John Duns Scotus’s theories of form and matter generally emphasize their independence. Prime matter exists without form; forms (angels) exist without matter. The plurality of forms suggests the soul’s independent individuality. These views open the possibility of the soul’s survival after bodily death as an immaterial substance. However, John Duns Scotus finds no philosophical arguments compelling enough to confirm this possibility, concluding that the soul’s immortality is known only through faith.

3.3 Universals and Individuation in Scotist Thought

The problem of universals concerns the metaphysical basis for applying the same predicate to multiple individuals. For example, both Socrates and Plato are human. Does this necessitate a universal reality – humanity – shared by both? Or is there no metaphysical commonality? Realists posit extra-mental universals; nominalists deny them. John Duns Scotus was a realist, tasked with explaining the nature and extra-mental existence of universals, specifically “humanity” shared by Socrates and Plato. He also addressed individuation: what distinguishes Socrates and Plato as distinct instances of the universal humanity?

John Duns Scotus termed the extra-mental universal the “common nature” (natura communis) and the principle of individuation the “haecceity” (haecceitas). Common nature is “indifferent” to existing in many individuals but exists extra-mentally only in particulars, where it is “contracted” by haecceity. Thus, humanity exists in both Socrates and Plato, individualized by Socrates’s haecceitas and Plato’s haecceitas. The humanity-of-Socrates and humanity-of-Plato are individual and non-repeatable, yet humanity itself is common, repeatable, and ontologically prior to its individual instantiations (Ordinatio 2, d. 3, pars 1, qq. 1–6, translated in Spade [1994], 57–113).

4. Theory of Knowledge in John Duns Scotus

4.1 Sensation and Abstraction in Scotist Epistemology

John Duns Scotus adopted the Aristotelian view that humans, uniquely among animals, possess both sensory and intellectual cognitive faculties. Senses are physical, while intellect is immaterial. For intellect to utilize sensory data, it must transform material sensory images into objects of understanding through abstraction. Abstraction, from Latin abstrahere (“to drag out”), involves the intellect extracting the universal from the material singular. The active intellect performs this, converting sensory “phantasms” into “intelligible species.” These species are actualized in the passive intellect, which receives and stores them. John Duns Scotus rejected a real distinction between active and passive intellect, viewing them as distinct functions of a single intellect.

Phantasms remain relevant even after abstraction. John Duns Scotus, like Aquinas, argued that intellect always understands by turning towards phantasms (Lectura 2, d. 3, pars 2, q. 1, n. 255). Using a concept requires sensory context, though the phantasms used may differ from those from which the concept was abstracted. For example, the concept of “dog” may be abstracted from dog phantasms, but its use can involve imagining a dog image or the Latin word for dog. John Duns Scotus emphasizes the necessity of sensory context for intellectual cognition.

However, this need for phantasms is considered temporary. John Duns Scotus believed it is specific to earthly life; in the afterlife, intellect will function without phantasms. Furthermore, in his later works, John Duns Scotus proposed “intuitive cognition,” an intellectual cognition that transcends phantasms, even in this life.

4.2 Intuitive Cognition: Direct Intellectual Grasp

John Duns Scotus contrasted intuitive cognition with abstractive cognition. Abstractive cognition involves universals that may or may not be instantiated. The concept “dog” defines dogness but doesn’t confirm the existence of any dog. Intuitive cognition, conversely, provides “information about how things are right now” (Pasnau [2002]). Sensory cognition is intuitive, as seeing or hearing a dog provides information about a specific, existing dog. John Duns Scotus made a bolder claim for intellectual intuitive cognition, where intellect cognizes a particular, existing thing directly, without phantasms or intelligible species (which are abstractive).

Intellectual intuitive cognition has two objects: external sensible objects and the soul’s own acts. Initially denying intuitive cognition of external objects, John Duns Scotus later affirmed its possibility. He consistently maintained the possibility of intuitive cognition of the soul’s acts (Cross 2014, 43–64). We must have intuitive cognition of external objects because we can intellectually cognize them as existing, forming propositions and syllogisms about them. For example, “This flower is red” requires intellectual cognition of “this flower” as existing. Sensible species of the flower’s shape and color are “promoted” by the agent intellect from material existence in a sense organ to immaterial existence in the intellect, enabling intellectual cognition. The role of sensible species explains why John Duns Scotus denied intuitive intellectual cognition of non-sensible objects like angels in this life.

We also possess intuitive cognition of our mental acts. Abstractive cognition provides a concept of “thinking about John Duns Scotus,” but intuitive cognition allows us to know that we are actually thinking about John Duns Scotus right now. This intuitive self-knowledge transcends sensible species, as intellectual acts are immaterial and not sensed.

4.3 Scotus’s Critique of Skepticism and Illuminationism

John Duns Scotus argued for the human intellect’s capacity for certain knowledge through its natural powers, without divine illumination. He opposed both skepticism, which denies certain knowledge, and illuminationism, which necessitates divine illumination for certainty. His critique is developed in response to Henry of Ghent in Ordinatio 1, d. 3, pars 1, q. 4 (van den Bercken [2016], 114–143).

Henry argued that truth involves relation to an “exemplar,” a mental item corresponding to reality. He distinguished between created exemplars (species abstracted from objects) and uncreated exemplars (divine ideas). Henry contended that created exemplars cannot provide certain knowledge due to the mutability of both the object and the soul. Mutability undermines immutability as a basis for certainty. Furthermore, created exemplars cannot differentiate between reality and dreams, as their content remains the same in both states. Henry concluded that certainty requires divine illumination through uncreated exemplars.

John Duns Scotus countered that if natural powers are as limited as Henry suggests, even divine illumination would fail. To Henry’s first argument, he replied that certainty is not achieved by knowing mutable objects as immutable. To the second, he noted that all mental acts, including illuminated understanding, are mutable, thus failing to provide an immutable foundation for certainty. To the third, he argued that if created exemplars inherently preclude certainty, adding more exemplars won’t solve the problem: “When something incompatible with certainty concurs, certainty cannot be attained” (Ordinatio 1, d. 3, pars 1, q. 4, n. 221).

John Duns Scotus argued that Henry’s arguments lead to skepticism, not illuminationism. He affirmed human capacity for certain knowledge through natural intellect. Certainty is attainable in four areas: First principles are self-evidently true upon intellectual apprehension. Syllogistic deductions from first principles inherit this certainty. Many causal judgments derived from experience are also certain. Our own mental acts possess certainty akin to first principles. Finally, certain propositions about present sense experience, properly vetted by intellect, are also known with certainty.

5. Ethics and Moral Psychology in Scotist Thought

5.1 The Natural Law in Scotist Ethics

For John Duns Scotus, natural law in the strict sense encompasses only moral propositions that are per se notae ex terminis (self-evident from their terms) and their deductive consequences (Ordinatio 3, d. 37, q. un.). Per se notae ex terminis implies analyticity and necessity, truths that even God cannot falsify. Thus, natural law in this strict sense is independent of God’s will. Even if John Duns Scotus is considered a divine-command theorist in some respects, his theory is not absolute; some moral truths are necessary and immutable, even for God.

These necessary moral truths are primarily found in the first tablet of the Decalogue (Ten Commandments), focusing on duties to God: You shall have no other gods before me, You shall not take the name of the Lord your God in vain, and Remember the Sabbath day to keep it holy. These commandments, concerning God’s nature and proper treatment, are considered part of the strict natural law. John Duns Scotus argues that “If God exists, then he is to be loved as God, and nothing else is to be worshiped as God, and no irreverence is to be done to him” is per se nota ex terminis. Given God’s definition, love, worship, and reverence are necessarily due to God.

However, even within the first tablet, commandments like the Sabbath day are not strictly natural law. “God is to be worshiped on Saturday” is neither self-evident nor analytic, and is no longer true for Christians who worship on Sunday. Even “God is to be worshiped at some time or other” lacks self-evidence. The closest analytic proposition is “God is not to be hated,” as God, by definition, is most worthy of love. This leaves only negative propositions in the strict natural law: prohibitions against hating God, worshiping other gods, or showing irreverence to God. The rest of the Decalogue, including the second tablet (duties to others), belongs to natural law in a weaker sense. These propositions are “highly consonant” with strict natural law but are not per se notae ex terminis or deductively derived from them. Crucially, these weaker natural law propositions are contingent and depend entirely on God’s will.

John Duns Scotus posits that God, being omniscient, is aware of all contingent propositions. God determines the truth values of these propositions. For example, “Unicorns exist” is contingent; its truth is determined by God’s will. Similarly, contingent moral propositions are determined by God’s will. For any such proposition L, God can will L to be true, making it part of the moral law, or will its contradictory, not-L. God’s choice is unqualifiedly free, without a fully adequate reason beyond God’s will itself. If there were a determining reason beyond God’s will, the propositions would be necessary, not contingent. God’s will is the ultimate explanation.

This parallels the contingency of creation. The existence of elephants but not unicorns is attributed to God’s will, a free act without external constraint. Similarly, the moral law, such as the obligation to honor parents but not cousins, is determined by God’s free will, without further explanation. God could have willed differently, but the existing moral order reflects God’s actual will.

(Recent critiques of this voluntaristic interpretation of John Duns Scotus’s moral law include Borland and Hillman 2017 and Ward 2019.)

5.2 Will, Freedom, and Morality in Scotist Ethics

John Duns Scotus consciously presented his understanding of freedom as an alternative to Aquinas’s. Aquinas rooted freedom in the will being intellectual appetite, distinct from sense appetite. Intellectual appetite is directed towards objects presented by intellect (universals), while sense appetite is directed towards objects presented by senses (particulars). Sense appetite is not free because senses present only particular objects. Intellectual appetite, dealing with universals encompassing multiple particulars, is free, offering various options. For example, the universal “goodness” includes many particular goods, providing the will with choices.

John Duns Scotus argued that mere intellectual appetite is insufficient for the kind of freedom essential for morality. He emphasized freedom at the moment of choice, not just across time. Aquinas’s view, suggesting different options over time, doesn’t capture the simultaneous availability of choices at the moment of decision. John Duns Scotus insisted that true freedom requires the ability to choose otherwise at the very moment of choosing.

This led to John Duns Scotus’s doctrine of the two affections of the will: affectio commodi (affection for advantage) and affectio iustitiae (affection for justice) (Ordinatio 2, d. 6, q. 2; 2, d. 39, q. 2; 3, d. 17, q. un.; and 3, d. 26, q. un.). Affectio commodi aligns with intellectual appetite, which John Duns Scotus distinguished as only part of the will, unlike Aquinas who equated intellectual appetite with the entire will. John Duns Scotus argued intellectual appetite alone cannot ensure genuine freedom. While acknowledging intellectual appetite’s role in pursuing happiness, he believed the will must encompass more for true freedom, namely affectio iustitiae.

Aquinas defined morality in terms of human happiness (eudaimonism). Our natural inclination towards happiness shapes moral norms. The will, as intellectual appetite, is naturally directed towards happiness. Good choices are those aligned with the ultimate end of happiness. John Duns Scotus, rejecting eudaimonism, argued that morality is not fundamentally tied to human flourishing. He believed libertarian freedom is essential for morality, which he found lacking in Aquinas’s eudaimonistic framework. John Duns Scotus rejected the notion that moral norms are intrinsically linked to human nature and happiness. God’s commands are not necessitated by human nature or conducive to happiness. Actions commanded are not essential for happiness, and forbidden actions are not incompatible with it. If the will were solely affectio commodi, directed only towards happiness, moral choice would be impossible, as moral law is not determined by happiness. John Duns Scotus thus relegated happiness to affectio commodi and assigned the properly moral dimension to affectio iustitiae.

Bibliography

Primary texts in Latin

Cuestiones Cuodlibetales. In Obras del Doctor Sutil, Juan Duns Escoto. Ed. Felix Alluntis. Madrid: Biblioteca de Autores Cristianos, 1963.
Opera Omnia. (“The Wadding edition”) Lyon, 1639; reprinted Hildesheim: Georg Olms Verlagsbuchhandlung, 1968. This is the best source for material not yet available in the critical editions. It does include some material now known to be inauthentic, and it prints as Book 1 of the Reportatio what is actually the Additiones magnae compiled and edited by Scotus’s student and secretary, William of Alnwick.
Opera Omnia. (“The Vatican edition”) Civitas Vaticana: Typis Polyglottis Vaticanis, 1950–2013. The Ordinatio (vol. I–XIV) and Lectura (vol. XVI–21).
Opera Philosophica. St. Bonaventure, NY: The Franciscan Institute, 1997–2006. The question-commentaries on Porphyry’s Isagoge and Aristotle’s Categories (vol. I), on Peri hermeneias and Sophistical Refutations, along with the Theoremata (vol. II), the Quaestiones super libros Metaphysicorum Aristotelis (vols. III–IV), and the Quaetiones super Secundum et Tertium de Anima (vol. V).
Notabilia Scoti super Metaphysicam: una testimonianza ritrovata dell’insegnamento di Duns Scoto sulla Metafisica, Giorgio Pini (ed.), Archivum Franciscanum Historicum, 89 (1996): 137–180.

Primary texts in English translation

Buckner, Edward, and Jack Zupko (trans., eds.), 2014. Duns Scotus on Time and Existence: The Questions on ‘De Interpretatione’, Washington, DC: Catholic University of America Press.
Bychkov, Oleg B., and Trent Pomplun, 2016. John Duns Scotus: The Report of the Paris Lecture: Reportatio IV-A. St. Bonaventure, NY: The Franciscan Institute. (An English translation and preliminary edition of the Latin text through distinction 10.)
Etzkorn, Girard J., and Allan B. Wolter, OFM, 1997–98. Questions on the Metaphysics of Aristotle by John Duns Scotus. St. Bonaventure, NY: The Franciscan Institute.
Jaczn, A. Vos, H. Veldhuis, A. A. Looman-Graaskamp, E. Dekker, and N. W. Den Bok (trans.), 1994. John Duns Scotus, Contingency and Freedom: Lectura I 39 (New Synthese Historical Library, 42), Dordrecht: Kluwer.
Newton, Lloyd (trans.), 2014. Questions on Aristotle’s Categories, Washington, DC: Catholic University of America Press.
Spade, Paul Vincent, 1994. Five Texts on the Mediaeval Problem of Universals. Indianapolis: Hackett Publishing Company.
van den Bercken, John, 2016. On Being and Cognition: Ordinatio 1.3. New York: Fordham University Press.
Vos, A., H. Veldhuis, E. Dekker, N.W. den Bok and A.J. Beck (eds.), 2003. Duns Scotus on Divine Love: Texts and Commentary on Goodness and Freedom, God and Humans, Aldershot: Ashgate.
Williams, Thomas, 2017. Duns Scotus: Selected Writings on Ethics. Oxford: Oxford University Press.
Wolter, Allan B., OFM, 1987. Duns Scotus: Philosophical Writings. Indianapolis: Hackett Publishing Company.
–––, 2000. A Treatise on Potency and Act. Questions on the Metaphysics of Aristotle Book IX, St. Bonaventure, NY: Franciscan Institute Publications.
–––, 2001. Political and Economic Philosophy, St. Bonaventure, NY: Franciscan Institute Publications.
Wolter, Allan B., OFM, and Felix Alluntis, 1975. John Duns Scotus, God and Creatures. The Quodlibetal Questions. Washington, D.C.: The Catholic University of America Press.
Wolter, Allan B., OFM, and Oleg V. Bychkov, 2004. The Examined Report of the Paris Lecture: Reportatio I-A. St. Bonaventure, NY: The Franciscan Institute. (An English translation and preliminary Latin edition.)

Secondary literature

Borland, Tully, and T. Allan Hillman 2017. “Scotus and God’s Arbitrary Will: A Reassessment,” American Catholic Philosophical Quarterly 91: 399–429.
Cross, Richard, 1999. Duns Scotus, Oxford: Oxford University Press.
–––, 2014. Duns Scotus’s Theory of Cognition, Oxford: Oxford University Press.
–––, 2016. Duns Scotus on God, New York: Routledge.
Frank, William A. and Allan B. Wolter, OFM, 1995. Duns Scotus: Metaphysician, Lafayette, IN: Purdue University Press, 1995.
Hoffmann, Tobias, 2002. Creatura intellecta: Die Ideen und Possibilien bei Duns Scotus mit Ausblick auf Franz von Mayronis, Poncius, und Mastrius, Münster: Aschendorff.
Ingham, Mary Beth, et al. (eds.), 2010–2012. Proceedings of the Quadruple Congress on Duns Scotus, 4 volumes, St. Bonaventure, NY: The Franciscan Institute.
Ingham, Mary Beth, and Mechthild Dreyer, 2004. The Philosophical Vision of John Duns Scotus: An Introduction, Washington, DC: The Catholic University of America Press.
King, Peter, 2002. “Scotus on Metaphysics,” in Williams 2002.
Pasnau, Robert, 2002. “Cognition,” in Williams 2002, 285–311.
Pini, Giorgio, 2002. Categories and Logic in Duns Scotus: An Interpretation of Aristotle’s Categories in the Late Thirteenth Century, Köln: Brill.
Vos, Antonie, 2018. The Theology of John Duns Scotus, Leiden: Brill.
Ward, Thomas M., 2014. John Duns Scotus on Parts, Wholes, and Hylomorphism, Leiden: Brill.
–––, 2019. “A Most Mitigated Friar: Scotus on Natural Law and Divine Freedom,” American Catholic Philosophical Quarterly 93: 385–409.
Williams, Thomas, 1995. “How Scotus Separates Morality from Happiness,” American Catholic Philosophical Quarterly, 69: 425–445. [Preprint available online.]
–––, 1998. “The Unmitigated Scotus,” Archiv für Geschichte der Philosophie, 80: 162–181. [Preprint available online.]
–––, 2000. “A Most Methodical Lover: On Scotus’s Arbitrary Creator,” Journal of the History of Philosophy, 38: 169–202. [Preprint available online.]
–––, 2002. The Cambridge Companion to Duns Scotus, New York: Cambridge University Press.
Wolter, Allan B., OFM, 1990. The Philosophical Theology of John Duns Scotus, Marilyn McCord Adams (ed.), Ithaca, NY: Cornell University Press.

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