Thomas Aquinas
Thomas Aquinas (c. 1225–1274) was an Italian Dominican friar, theologian, and philosopher whose synthesis of Christian doctrine with Aristotelian philosophy became the cornerstone of Latin medieval thought. Born into a minor noble family near Aquino, he received his early education at Monte Cassino and the University of Naples, where he first encountered Aristotle. Against his family’s wishes, he joined the Dominican Order and studied under Albertus Magnus in Paris and Cologne, absorbing and deepening the new Aristotelian currents entering Western Europe. Aquinas served as master of theology at the University of Paris and later taught in various Italian centers, composing an extraordinary corpus that includes the Summa Theologiae, the Summa contra Gentiles, and major commentaries on Aristotle. His work integrates metaphysics, theology, ethics, and political theory into a systematic whole, marked by a careful distinction between nature and grace, reason and revelation. He formulated influential accounts of analogy, act and potency, natural law, and the relationship between faith and reason. Although some of his positions were contested shortly after his death, he was canonized in 1323 and later declared a Doctor of the Church. Thomism, the tradition inspired by his thought, continues to shape Catholic theology and contemporary philosophy.
At a Glance
- Born
- c. 1225(approx.) — Roccasecca, near Aquino, Kingdom of Sicily
- Died
- 1274-03-07 — Fossanova Abbey, near Terracina, Papal StatesCause: Illness (after head injury from accident while traveling to the Second Council of Lyon)
- Floruit
- c. 1245–1274Period of Thomas Aquinas’s main teaching and writing activity in Paris and Italy.
- Active In
- Kingdom of Sicily (Italy), Kingdom of France, Papal States, Holy Roman Empire
- Interests
- MetaphysicsPhilosophy of religionTheologyEthicsNatural lawEpistemologyPhilosophical anthropologyPolitical philosophy
Thomas Aquinas articulates a comprehensive synthesis in which human reason and divine revelation, nature and grace, are distinct yet fundamentally ordered toward the same ultimate end: the knowledge and love of God. Grounded in a metaphysics of act and potency, and of real distinction between essence and existence in creatures, he holds that all finite beings participate analogically in God, who alone is ipsum esse subsistens (subsistent being itself). From this ontology he derives a natural law ethic, according to which objective moral norms flow from the rational creature’s participation in the eternal law and are directed to beatitude. Philosophy, using natural reason, can demonstrate certain truths about God, the soul, and morality, while theology—rooted in revelation—completes and elevates this knowledge, guiding humans to the supernatural end of the beatific vision.
Summa Theologiae
Composed: c. 1265–1273
Summa contra Gentiles
Composed: c. 1259–1265
Commentaria in Metaphysicam Aristotelis
Composed: c. 1268–1272
Sententia libri Ethicorum
Composed: c. 1269–1272
De ente et essentia
Composed: c. 1252–1256
Quaestiones disputatae de veritate
Composed: c. 1256–1259
Quaestiones disputatae de anima
Composed: c. 1265–1266
De regno ad regem Cypri
Composed: c. 1265–1267
Compendium theologiae
Composed: c. 1265–1273
Catena aurea in quatuor Evangelia
Composed: c. 1262–1264
The existence of God and other like truths about God, which can be known by natural reason, are not articles of faith but preambles to the articles.— Summa Theologiae, I, q. 2, a. 2, ad 1
Here Aquinas distinguishes between what reason can know about God and what is known only by revelation, clarifying the relationship between philosophy and theology.
Law is nothing else than an ordinance of reason for the common good, made by him who has care of the community, and promulgated.— Summa Theologiae, I–II, q. 90, a. 4
A classic definition of law that underpins his theory of natural law and political authority, emphasizing rational ordering to the common good.
Happiness is nothing else than the enjoyment of the highest good.— Summa Theologiae, I–II, q. 3, a. 2
Part of his analysis of human beatitude, where he argues that true happiness consists only in the vision of God, not in any created good.
Grace does not destroy nature but perfects it.— Summa Theologiae, I, q. 1, a. 8, ad 2 (paraphrasing the principle: gratia non tollit naturam, sed perficit)
A programmatic statement of his view that the supernatural order elevates and fulfills human nature rather than negating it.
All that is received is received according to the mode of the receiver.— Summa Theologiae, I, q. 75, a. 5, ad 4 (echoing a common scholastic principle)
Expresses Aquinas’s epistemological and metaphysical conviction that knowledge and causality are conditioned by the capacities of the subject.
Formative Monastic and University Years (c. 1230–1244)
As an oblate at Monte Cassino and a student at the University of Naples, Thomas encountered the liturgical, Augustinian, and monastic tradition alongside newly translated works of Aristotle and Arab commentators, forming the dual heritage—patristic and Aristotelian—that structured his later synthesis.
Dominican Novitiate and Apprenticeship under Albertus Magnus (1244–1252)
After entering the Dominicans, Thomas studied in Paris and Cologne under Albertus Magnus, where he mastered the full range of Aristotelian philosophy and began his early commentaries and disputed questions, refining his method of rigorous quaestiones and systematic exposition.
First Paris Regency and Early Systematic Works (1252–1259)
During his first period as master at Paris, Thomas produced Scriptural commentaries, disputed questions on truth and the soul, and the Summa contra Gentiles, consolidating his view of the harmony between faith and reason and developing his metaphysical framework of act and potency, essence and existence.
Italian Teaching and Composition of the Summa Theologiae (1265–1272)
Teaching in Dominican studia in Rome and central Italy, Thomas undertook his most ambitious project, the Summa Theologiae, while also writing important works on law, virtues, and the sacraments, achieving a mature synthesis of theology, metaphysics, and moral philosophy oriented toward the beatific vision.
Final Paris Regency and Mystical Silence (1272–1274)
Returning to academic conflict in Paris over mendicant orders and Aristotelianism, Thomas defended his positions in controversial questions, then, after a reported mystical experience in 1273, largely ceased writing, leaving some works, including parts of the Summa Theologiae, unfinished at his death.
1. Introduction
Thomas Aquinas (c. 1225–1274) is widely regarded as the most systematic and influential thinker of Latin medieval Christianity. A Dominican friar working in the High Middle Ages, he brought together patristic theology, especially Augustine, with the newly translated corpus of Aristotle and with Islamic and Jewish philosophy, producing what later tradition calls Thomism. His synthesis has shaped subsequent discussions of metaphysics, theology, ethics, and law in both religious and secular contexts.
Aquinas’s thought is usually situated within Scholasticism, the university-based intellectual tradition that employed rigorous argument, precise distinctions, and close attention to authorities. Proponents of his enduring relevance point to his integrated vision of faith and reason, his account of being, essence, and existence, and his theories of natural law and virtue as providing a coherent framework for understanding reality, morality, and political life. Critics and alternative traditions, however, have questioned his reliance on Aristotelian categories, his hierarchical cosmology, and his assumptions about revelation and ecclesial authority.
His major works, including the Summa Theologiae and Summa contra Gentiles, along with extensive commentaries on Aristotle and the Bible, attempt a comprehensive ordering of knowledge around the ultimate end of human beings: the beatific vision of God. Some interpreters emphasize the metaphysical core of this project, centered on God as ipsum esse subsistens (subsistent being itself); others stress its practical orientation toward moral formation, law, and the common good.
Modern scholarship approaches Aquinas from multiple angles: as a systematic theologian, a metaphysician of act and potency, a theorist of natural law, and a historical figure in the political and institutional conflicts of the thirteenth-century universities. This entry traces his life and context, outlines his principal doctrines and methods, and surveys the diverse ways in which his ideas have been received, developed, and contested.
2. Life and Historical Context
2.1 Family Background and Early Environment
Thomas was born c. 1225 at Roccasecca, a castle held by the counts of Aquino in the Kingdom of Sicily. His noble family was entangled in the complex politics of the Hohenstaufen monarchy. Proximity to Monte Cassino, the leading Benedictine abbey, placed Thomas within an older monastic and Augustinian culture even as the emerging universities were transforming intellectual life.
2.2 The Thirteenth-Century Church and Empire
Aquinas’s lifetime coincided with intense conflict between the papacy and the Holy Roman Emperor, especially Frederick II. Historians argue that this context shaped the tension in his work between ecclesial authority and temporal power. While some scholars see his political writings as indirectly reflecting papal positions, others maintain that his theoretical account of law and the common good transcends immediate polemics.
2.3 The Rise of Universities and Mendicant Orders
The thirteenth century saw the consolidation of universities such as Paris and Naples and the rise of mendicant orders (Dominicans and Franciscans). Aquinas joined the Dominicans, an order dedicated to preaching and study, and spent much of his life within their studia and in university faculties. Debates over the status of mendicants in the university and in urban life formed the institutional backdrop for his teaching career.
2.4 The Aristotelian Turn
During Aquinas’s formative years, a large body of Aristotle’s works, accompanied by Arabic and Jewish commentaries, became available in Latin. Their reception provoked both enthusiasm and anxiety, especially because of perceived tensions with Christian doctrine on the soul, creation, and providence. Aquinas’s project to appropriate Latin Aristotelianism within Christian theology must be understood against this backdrop of translation, controversy, and ecclesiastical regulation.
2.5 Intellectual and Ecclesiastical Events
Aquinas’s activity intersected with major ecclesiastical events: the condemnation of certain Aristotelian theses at Paris (1210, 1215, 1231), the disputes over mendicant privileges, and preparations for the Second Council of Lyon, during whose journey he died in 1274. Later condemnations of 1277, though posthumous, indicate how closely his ideas were tied to the broader contest over the place of philosophy in theology. Scholars differ on how far these events influenced the development of his positions versus simply affecting their reception.
3. Education, Dominican Vocation, and Early Influences
3.1 Monte Cassino and Naples
As a child, Thomas was placed as an oblate at Monte Cassino, where he received a monastic education grounded in Scripture, the Church Fathers, and the Rule of Benedict. This period is often cited as the source of his liturgical sensitivity and Augustinian themes. Around his early teens he continued studies at the newly founded University of Naples, where he encountered Aristotelian logic and natural philosophy through translations and commentaries then circulating in southern Italy.
At Naples, Thomas appears to have met members of the Dominican Order and possibly first read works of Aristotle in the versions promoted by translators associated with Frederick II’s court. Historians debate the exact curriculum, but most agree that this urban, university setting introduced him to the tensions between traditional monastic learning and the new scholastic culture.
3.2 Entrance into the Dominicans
In 1244 Thomas entered the Dominicans in Naples, against his family’s wishes. Hagiographical sources recount his relatives’ attempts to remove him from the order; historians treat some details cautiously but agree that significant family resistance occurred, reflecting wider social suspicion toward mendicant poverty and mobility among the nobility.
The Dominican vocation shaped Aquinas’s orientation toward study as a service to preaching and pastoral care. Later interpreters emphasize that his systematic works were composed within a pedagogical and homiletic mission, not as purely academic exercises.
3.3 Apprenticeship under Albertus Magnus
Transferred to Paris and then Cologne, Thomas studied under Albertus Magnus, one of the foremost interpreters of Aristotle. Albert’s broad interest in natural science and philosophy influenced Thomas’s openness to integrating non-Christian sources. Some scholars portray Albert as decisive for Thomas’s metaphysics of form and matter; others view Thomas as moving beyond Albert in articulating the real distinction between essence and existence.
3.4 Early Intellectual Milieu
During these years, Thomas engaged with a wide array of authorities: Augustine, Pseudo-Dionysius, Boethius, Islamic thinkers such as Avicenna and Averroes, and Jewish authors like Maimonides. His earliest independent writings, including De ente et essentia, emerge from this context of disputed questions and commentary.
Interpretations diverge over which influence was primary. Augustinian-oriented scholars stress the continuing dominance of patristic themes; Aristotelian-oriented readers highlight his methodological and conceptual indebtedness to Aristotle and Avicenna. Many contemporary commentators see Aquinas’s originality precisely in his ability to hold these strands together without reducing one to the other.
4. Academic Career in Paris and Italy
4.1 First Paris Regency (1256–1259)
After advanced study and work as a baccalaureus on Peter Lombard’s Sentences, Aquinas attained the rank of Master of Theology at the University of Paris in 1256. As a regent master in the Dominican chair, he lectured on Scripture, held public disputations, and produced early systematic works. This period coincided with controversy over the place of mendicant friars in the university. Aquinas contributed to these debates, defending mendicant teaching rights within the framework of ecclesial hierarchy and the common good of learning.
4.2 Italian Period (c. 1259–1268)
Summoned back to Italy, Aquinas taught in Dominican studia in Orvieto, Rome, Viterbo, and other centers. Here he served both as a teacher of friars and as a papal theologian in various capacities. During this time he began the Summa Theologiae and worked on the Catena aurea and other major projects, tailoring his pedagogy to a broader clerical audience beyond the university milieu.
Scholars debate the degree to which Roman curial concerns influenced his focus on law, virtues, and pastoral issues during these years. Some interpret the Summa as designed primarily as a training manual for preachers; others view it as an ambitious reordering of the entire theological curriculum.
4.3 Second Paris Regency (1268–1272)
Aquinas returned to Paris amid renewed disputes about the role of Aristotle and about Latin Averroism, particularly doctrines on the eternity of the world and the unity of the intellect. As regent master, he engaged directly with these issues in works such as De unitate intellectus contra Averroistas. His Aristotelian commentaries from this period, including on the Metaphysics and Nicomachean Ethics, reflect close engagement with philosophical teaching in the arts faculty.
Contemporary historians view this regency as a moment of heightened philosophical self-consciousness, in which Aquinas clarified his positions on the autonomy of natural reason while insisting on its subordination to revealed theology.
4.4 Final Italian Years and Last Journey
In 1272 Aquinas accepted a position to organize a new studium generale for the Dominicans in Naples. There he continued teaching and writing until the mystical experience of late 1273, after which he largely ceased dictation. In early 1274 he set out for the Second Council of Lyon at papal request but fell ill and died en route at Fossanova Abbey.
Biographers debate how far the reported mystical episode altered his thinking or simply his willingness to write. The unfinished state of the Summa Theologiae and some commentaries has led to ongoing scholarly speculation about how he might have further developed or revised his doctrines had he lived longer.
5. Major Works and Literary Corpus
5.1 Genres and Aims
Aquinas’s corpus spans multiple literary forms typical of scholastic production:
| Genre | Examples | Primary Setting/Use |
|---|---|---|
| Scriptural commentaries | Commentaries on John, Matthew, Paul | Theology curriculum, preaching support |
| Sentences commentaries | Scriptum super Sententiis | Required academic exercise at Paris |
| Disputed questions | De veritate, De anima, De malo | Public theological disputations |
| Quaestio-style summae | Summa Theologiae, Summa contra Gentiles | Systematic teaching and reference |
| Aristotelian commentaries | In Metaphysicam, In Ethicam | Engagement with arts faculty philosophy |
| Short treatises and opúscula | De ente et essentia, De regno | Responses to specific problems or patrons |
Scholars emphasize that these forms were shaped by institutional needs: university courses, Dominican instruction, and pastoral requirements.
5.2 Systematic Works
The Summa Theologiae (c. 1265–1273) is Aquinas’s best-known work, planned in three main parts (with the third incomplete). It addresses God, creation, human acts, virtues, law, Christ, and the sacraments in a highly structured sequence of questions and articles. Interpreters differ over its primary function—handbook for beginners, synthesis of prior work, or comprehensive reordering of theology—but agree on its centrality for understanding his mature thought.
The Summa contra Gentiles (c. 1259–1265) is more argumentative and apologetic, structured to establish, defend, and distinguish truths accessible to reason from those known only by revelation. Its exact audience—Muslim scholars, skeptical intellectuals, or Christian students—remains debated.
5.3 Disputed Questions and Treatises
Works like Quaestiones disputatae de veritate and de anima record highly formalized public debates, often delving more deeply into specific topics than the Summae. The short treatise De ente et essentia is central for his metaphysics of being, while De regno (with partially disputed authorship) addresses kingship and political order.
5.4 Commentaries
Aquinas’s extensive biblical commentaries and Aristotelian commentaries are increasingly regarded as essential for interpreting his system. Some modern scholars highlight them as more historically sensitive to source texts; others see them as vehicles for inserting his own positions within an authoritative framework.
Questions of authorship surround a small number of works, and textual criticism continues to refine the corpus and chronology, affecting interpretations of his intellectual development.
6. Philosophical Method and Scholastic Style
6.1 The Quaestio Format
A defining feature of Aquinas’s method is the scholastic question (quaestio disputata) structure, refined in works like the Summa Theologiae:
- Statement of the question
- Objections (arguments against the position he will adopt)
- Sed contra: a brief counter-statement grounded in authority
- Respondeo: a systematic solution, often introducing distinctions
- Replies to each objection
This format aims to present opposing views fairly and integrate them, where possible, into a more comprehensive resolution. Some modern interpreters highlight its dialogical and pedagogical nature; others criticize it as overly schematic or constrained by deference to authority.
6.2 Use of Authorities and Reason
Aquinas distinguishes philosophical arguments (from natural reason) from theological arguments (from revelation and Church teaching). In philosophical contexts, he appeals to Aristotle, Avicenna, and others, often reworking their positions. In theology, he gives special weight to Scripture and the Fathers, particularly Augustine.
He also distinguishes demonstration (strict proof) from probable argument and argument from authority. While insisting that ultimate truths of faith rest on revelation, he defends the use of rational arguments as “preambles” and clarifications. Some commentators see this as an early articulation of disciplinary differentiation; critics suggest it still subordinates philosophy too tightly to theology.
6.3 Distinctions and Conceptual Analysis
Aquinas’s method relies heavily on precise distinctions—for example between essence and existence, substance and accident, act and potency. He frequently introduces “formal,” “virtual,” or “real” distinctions to explain complex relations.
Supporters regard this as a powerful analytical tool that allows nuanced positions between simple affirmation and denial. Others argue that the proliferation of distinctions can obscure underlying assumptions and make his texts difficult to interpret.
6.4 Disputation and Pedagogy
Public disputations, reflected in the Quaestiones disputatae, formed a central part of his teaching. There he addresses objections raised by students and colleagues, including non-Christian and heterodox views. Some modern scholars interpret this as fostering a culture of disciplined intellectual disagreement; others note that the framework still presupposes institutional limits set by ecclesiastical authority.
7. Metaphysics: Being, Essence, and Existence
7.1 Act, Potency, and the Structure of Beings
Aquinas adopts and develops the Aristotelian distinction between act (actus) and potency (potentia) to explain change and composition. Every finite being is a composite of potentials and their actualization, whether in terms of matter and form or other metaphysical principles. This structure allows him to affirm both the stability of substances and the reality of becoming.
Interpreters differ on the extent to which this framework is purely Aristotelian or significantly reshaped by Neoplatonic participation themes.
7.2 Essence and Existence
In De ente et essentia and the Summa Theologiae, Aquinas argues for a real composition in creatures between essence (what a thing is) and existence (that it is). Created essences are capacities to receive existence; only in God are essence and existence identical.
Proponents of this “existential Thomism” (e.g., Étienne Gilson) see this as Aquinas’s most original metaphysical move, grounding a dynamic view of being as act of existence (actus essendi). Other interpreters, influenced by analytic metaphysics, sometimes treat the distinction more modestly, as a way of speaking about modality or dependence rather than a separate ontological component.
7.3 Participation and the Analogy of Being
Finite beings participate in being and goodness, which are fully realized only in God. This leads to the doctrine of the analogy of being (analogia entis): terms like “being” or “good” are neither univocal nor purely equivocal between God and creatures but predicated according to ordered likenesses.
“Because we cannot know what God is, but only what He is not, we have no means for considering how God is, but rather how He is not.”
— Thomas Aquinas, Summa Theologiae I, q. 3, prologue (paraphrased from Latin)
Some scholars emphasize the apophatic (negative) thrust of this view; others stress that analogy still yields genuine, if limited, knowledge of God. Critics, especially later nominalists, question whether analogical predication secures clear meaning.
7.4 Substance, Accidents, and Causality
Aquinas maintains a classical account of substance and accident, integrating it with a robust notion of primary and secondary causes. God is the primary cause who gives being and efficacy to created causes, which truly operate as secondary causes within their own order. Discussions of divine causality, concurrence, and providence in his metaphysics underlie later debates about freedom, determinism, and the autonomy of nature, with varying interpretations about how strongly God’s causality conditions created action.
8. Theology of God: Attributes, Trinity, and Creation
8.1 Knowledge of God and Divine Simplicity
Aquinas holds that some truths about God—such as existence and certain attributes—are accessible to natural reason, while the inner life of God (Trinity, Incarnation) is known only by revelation. He begins theology with divine simplicity, arguing that God is not composed of parts, form and matter, or essence and existence. From simplicity he derives attributes like infinity, immutability, and eternity.
Supporters see this as securing God’s absolute transcendence; critics argue it risks making God seem impersonal or incompatible with relational language.
8.2 Divine Attributes and Analogy
Using the analogy of being, Aquinas affirms that predicates such as “wise,” “good,” or “just” apply to God as pure act of being, though in a way proportionally different from creatures. He distinguishes between attributes of essence (e.g., goodness) and relations (e.g., paternity) that will ground Trinitarian distinctions.
Interpretive debates concern whether Aquinas’s metaphysical attributes dominate his understanding of the biblical God or whether they function as rational clarifications of scriptural revelation.
8.3 Trinity
In Summa Theologiae I, qq. 27–43, Aquinas treats the Trinity through the procession of Word and Love, using psychological analogies: the Son proceeds as Word from the Father’s intellect; the Spirit proceeds as Love from the will of Father and Son.
Some scholars praise this as an elegant synthesis of patristic theology and philosophical psychology. Others, particularly modern trinitarian theologians, question its adequacy as a model of interpersonal communion, suggesting it may over-intellectualize divine life.
8.4 Creation, Conservation, and Providence
Aquinas asserts creation ex nihilo as a truth of faith, while allowing that reason cannot demonstrate the temporal beginning of the world, only its dependence on God as cause of being. He holds that God not only creates but also conserves creatures in existence and cooperates with their actions as primary cause.
His doctrine of providence maintains that all events fall under divine governance, yet creatures act according to their own natures and freedom. Debates persist about how to interpret this concurrence: some emphasize strong divine premotion, others a looser permission allowing for creaturely autonomy.
9. Human Nature and Knowledge
9.1 Soul–Body Unity
Aquinas defines the human as a rational animal, a single substance composed of soul as substantial form and body as matter. The rational soul is immaterial and subsistent yet naturally ordained to inform a body. This position aims to mediate between dualism and materialism.
Supporters regard his hylomorphic account as a powerful alternative to both; critics contend that the subsistence of the soul introduces a dualistic tension, especially regarding personal identity after death.
9.2 Powers of the Soul
He distinguishes vegetative, sensitive, and intellective powers, integrated within one soul. Sensitive faculties (sensation, imagination, appetite) mediate between bodily conditions and intellectual activity. This layered psychology informs his ethics, where passions are neither purely irrational nor wholly under reason’s control.
Some modern commentators appreciate this as a forerunner of holistic accounts of the person; others find the faculty psychology too rigid by contemporary cognitive standards.
9.3 Theory of Knowledge
Aquinas adopts an abstractionist epistemology. All human knowledge begins in the senses: external senses receive forms, the imagination retains phantasms, and the agent intellect abstracts intelligible species from these, which are then received by the possible intellect.
He insists that humans have no innate concepts and no direct intellectual intuition of material things or of God in this life. Lines of interpretation diverge over how to understand the status of intelligible species—whether as psychological intermediaries, representational contents, or structural conditions for cognition.
9.4 Self-Knowledge and Knowledge of God
Humans know their own soul indirectly, by reflecting on their acts, rather than by an immediate intuition. Knowledge of God in this life is analogical and discursive, based on reasoning from creatures to their cause and on accepting revelation by faith.
“We cannot know what God is, but only what He is not, and how other beings stand in relation to Him.”
— Thomas Aquinas, Summa contra Gentiles I, c. 30 (paraphrased)
Some scholars emphasize the humility of this epistemology; others argue that it restricts philosophical theology more than is necessary or coherent.
10. Ethics, Virtue, and the Beatific Vision
10.1 Human End and Happiness
In the Summa Theologiae I–II, Aquinas argues that all human actions are ordered toward an ultimate end (finis), which he identifies with happiness (beatitudo). After evaluating various candidates—wealth, pleasure, honor, contemplation—he concludes that perfect happiness consists only in the beatific vision, the direct intuitive knowledge of God’s essence in the next life.
Supporters find in this a theologically grounded perfection of Aristotelian eudaimonism; critics question whether it sufficiently values temporal goods or allows for plural conceptions of flourishing.
10.2 Virtue Theory
Aquinas develops a rich account of virtues as stable habits. He distinguishes:
| Type of Virtue | Examples | Source/Orientation |
|---|---|---|
| Intellectual virtues | wisdom, understanding | perfect reason itself |
| Moral virtues | prudence, justice, temperance, fortitude | ordered passions and actions |
| Theological virtues | faith, hope, charity | infused by God, oriented to God |
He integrates Aristotelian moral virtues with specifically Christian theological virtues. Some interpreters emphasize the continuity with classical virtue ethics; others underscore the transformation introduced by grace and charity.
10.3 Passions, Habits, and Freedom
Aquinas treats passions as natural movements of the sensitive appetite, which can be rightly ordered by reason and virtue. He rejects the view that moral perfection requires suppression of emotion; rather, well-formed passions support virtuous action.
On free choice, he holds that the will necessarily seeks happiness but is free regarding particular means, under the guidance of reason. Debates persist about how his account of freedom relates to his views on divine causality and predestination.
10.4 Grace and Merit
Ethics in Aquinas is inseparable from grace. Natural virtues can lead to limited flourishing, but supernatural beatitude requires infused virtues and divine help. He articulates a doctrine of merit whereby actions done in grace, empowered by God yet truly human, can be rewarded with increased grace and glory.
Critics worry that this framework may appear transactional; defenders argue that it expresses participatory friendship with God.
10.5 The Beatific Vision
In Summa Theologiae I, q. 12 and elsewhere, Aquinas maintains that the beatific vision is an immediate, unmediated intuition of God’s essence, granted by a created “light of glory.” It fulfills the deepest natural desire of the intellect for truth, yet surpasses natural capacity.
Some modern theologians highlight the contemplative orientation of this account; others raise questions about its compatibility with more relational or historical understandings of salvation.
11. Law, Politics, and the Common Good
11.1 Fourfold Scheme of Law
Aquinas’s political and legal thought centers on a fourfold division of law (Summa Theologiae I–II, qq. 90–97):
| Type of Law | Description |
|---|---|
| Eternal Law | God’s rational governance of all creation |
| Natural Law | Rational creature’s participation in eternal law |
| Human (Positive) Law | Concrete determinations by human authorities |
| Divine Law | Special revelation ordering to supernatural end |
This structure allows him to link cosmic order, moral norms, and civil legislation. Proponents regard this as foundational for natural law theories; critics claim it presupposes a teleological metaphysics not widely shared today.
“Law is nothing else than an ordinance of reason for the common good, made by him who has care of the community, and promulgated.”
— Thomas Aquinas, Summa Theologiae I–II, q. 90, a. 4
11.2 Natural Law and Moral Principles
Natural law consists of general precepts knowable by reason (e.g., pursue good, avoid evil; preserve life; live in society). Aquinas allows for cultural variation in specific applications while maintaining universal moral structure.
Some interpreters emphasize its flexibility and compatibility with plural legal systems; others criticize its reliance on controversial claims about human nature and purposes.
11.3 Political Authority and Regimes
In Summa Theologiae and the treatise De regno (authorship partly disputed), Aquinas describes political authority as natural and necessary for achieving the common good. He views kingship as the best form when ordered toward the common good, but warns against tyranny and permits, under conditions, resistance or deposition.
Debates among scholars focus on whether Aquinas is fundamentally monarchist, mixed-constitutionalist, or offers a more general account adaptable to various regimes. Modern political theorists also discuss his distinction between spiritual and temporal powers and its implications for church–state relations.
11.4 Property, Justice, and War
Aquinas defends private property as reasonable for social order while insisting that in cases of extreme need, use of goods can revert to common. His treatment of justice includes both commutative (between individuals) and distributive (within the community) aspects.
On war, he articulates criteria often cited as classical just war doctrine: legitimate authority, just cause, and right intention. While some regard this as a humane constraint on violence, others question its adequacy in the face of modern warfare and power asymmetries.
12. Faith, Reason, and the Preambles of Faith
12.1 Distinguishing Faith and Reason
Aquinas distinguishes philosophical knowledge gained by natural reason from theological faith based on divine revelation. Both originate in God and, he argues, cannot ultimately contradict. Apparent conflicts stem from human error in interpretation.
He identifies truths about God and morality that are in principle knowable by reason (e.g., God’s existence, some attributes, basic ethical norms) and others accessible only through revelation (e.g., Trinity, Incarnation, specific sacramental economy).
12.2 Preambles of Faith
The “preambles of faith” (praeambula fidei) are truths that can be demonstrated philosophically yet are also taught by revelation, such as the existence of God and the natural immortality of the soul.
“The existence of God and other like truths about God, which can be known by natural reason, are not articles of faith but preambles to the articles.”
— Thomas Aquinas, Summa Theologiae I, q. 2, a. 2, ad 1
Supporters see this distinction as allowing cooperation between philosophy and theology while preserving their autonomy. Critics, especially some later fideists, hold that it overestimates human reason; others, conversely, claim it unnecessarily restricts rational inquiry.
12.3 Demonstrations of God’s Existence
In Summa Theologiae I, q. 2, a. 3, Aquinas presents the Five Ways, arguments from motion, causality, contingency, degrees of perfection, and order in the world to a first cause or ultimate end. He treats these as philosophical arguments accessible to unaided reason.
Interpretations of the Five Ways vary widely: some read them as strict metaphysical proofs; others as probabilistic pointers. Contemporary analytic philosophers debate their soundness under modern scientific assumptions, while historians emphasize their embedding in a broader Aristotelian metaphysics.
12.4 The Rationality of Faith
For Aquinas, faith (fides) is an assent to revealed truth moved by God’s grace and grounded in the authority of God speaking. Reason can show that believing is not irrational by demonstrating signs of credibility (miracles, continuity of doctrine, Church expansion), but it cannot compel faith.
Some modern thinkers find in this a sophisticated account of rational trust; critics question whether his model sufficiently acknowledges religious pluralism or the autonomy of critical historical inquiry.
13. Reception, Condemnations, and Canonization
13.1 Immediate Reception and Controversies
After Aquinas’s death in 1274, his ideas quickly became the subject of controversy. In 1277, the Bishop of Paris, Étienne Tempier, condemned 219 propositions, some overlapping with or associated by opponents with Thomistic positions (e.g., on the eternity of the world as philosophically conceivable, or on the unity of substantial form). Aquinas himself was not named, and scholars debate which condemned theses genuinely reflect his views.
Reactions among contemporaries were mixed: some Dominicans promoted his works vigorously; certain Franciscans, influenced by Bonaventure and later Duns Scotus, criticized his metaphysics and theology of grace.
13.2 Institutionalization and Canonization
Despite early resistance, Aquinas’s reputation grew. The Dominican Order strongly championed him, and his teaching was gradually integrated into university curricula. In 1323, Pope John XXII canonized him, recognizing his sanctity and doctrinal importance. In 1567, Pius V declared him a Doctor of the Church, solidifying his standing as a normative theologian in Roman Catholicism.
Some historians interpret these developments as part of broader efforts to standardize doctrine, especially in the context of late medieval controversies and later the Reformation. Others caution against viewing Thomism as fully dominant, noting the persistent influence of alternative schools.
13.3 Late Medieval and Early Modern Assessments
In the later Middle Ages, Thomism coexisted and competed with Scotism, Ockhamism, and humanist currents. Thomists debated internal issues such as grace and predestination (e.g., the Bañezian–Molinist controversies), showing that “Thomism” itself was not monolithic.
Reformers like Luther and Calvin engaged selectively with Aquinas, often critically, though some of his philosophical categories persisted in Protestant scholasticism. Early modern philosophers such as Descartes and Leibniz appropriated or reworked elements of his metaphysics, while also rejecting key premises.
13.4 Modern Evaluations of the Condemnations
Modern scholarship reassesses the 1277 condemnations and their impact. Some argue that the condemnations curtailed Thomist Aristotelianism and opened space for alternative scientific and philosophical developments. Others contend that Aquinas’s positions remained influential and that the condemnations were more limited in practical effect.
Debate continues about whether Aquinas should be seen primarily as a victim of institutional suspicion or as one voice among many in a plural scholastic landscape.
14. Thomism, Neo-Thomism, and Modern Interpretations
14.1 Thomist Schools
From the fourteenth century onward, Thomism developed into various schools, often centered in Dominican institutions and universities in Spain, Italy, and elsewhere. Commentators such as Cajetan and John of St. Thomas systematized, refined, and occasionally modified Aquinas’s positions.
These commentators became major sources for early modern philosophy and theology, though some modern scholars argue that their interpretations sometimes diverge significantly from Aquinas’s own texts.
14.2 Neo-Thomism and the 19th–20th Centuries
In 1879, Pope Leo XIII’s encyclical Aeterni Patris called for a “return to St Thomas,” sparking Neo-Thomism. Figures such as Jacques Maritain, Étienne Gilson, and Garrigou-Lagrange advanced distinct readings:
| Strand of Neo-Thomism | Emphasis |
|---|---|
| Existential Thomism | Primacy of act of existence (esse) |
| Transcendental Thomism | Dialogue with Kant, subjectivity (e.g., Rahner, Maréchal) |
| Strict/Manualist Thomism | Doctrinal clarity, scholastic commentaries |
Supporters see Neo-Thomism as providing a robust metaphysical and ethical foundation in modernity; critics object that it sometimes fossilized Aquinas into rigid systems or under-engaged with contemporary science and pluralism.
14.3 Post–Vatican II and Contemporary Readings
After the Second Vatican Council, Thomism was no longer mandated in Catholic seminaries, leading to diversification. New interpretations emerged:
- Historical Thomism: situating Aquinas strictly within his 13th‑century context.
- Analytic Thomism: engaging with analytic philosophy on metaphysics, action theory, and philosophy of mind (e.g., Geach, Anscombe, Haldane, Stump).
- Radical Orthodoxy and ressourcement approaches: using Aquinas to critique modern secular reason.
Some theologians critique aspects of Thomism as insufficiently attentive to history, narrative, or liberation concerns, while others find in his metaphysics and ethics resources for ecological and social thought.
14.4 Ecumenical and Philosophical Appropriations
Non-Catholic thinkers, including some Protestants and Eastern Orthodox theologians, selectively adopt Thomistic ideas on natural law, virtue, and participation. In secular philosophy, Aquinas is discussed in connection with natural theology, virtue ethics, and theories of law and rights.
Debate persists over whether “Thomism” names a unified tradition or a family of often divergent interpretations grounded in Aquinas’s texts but shaped by later concerns.
15. Legacy and Historical Significance
15.1 Influence on Theology and Philosophy
Aquinas’s integration of Aristotelian philosophy with Christian doctrine has had lasting impact on Christian theology, particularly within Roman Catholicism, where his work often serves as a reference point for doctrinal formulations. In philosophy, his metaphysics of being, participation, and primary and secondary causes continues to inform discussions of causality, existence, and theism.
Many virtue ethicists draw on his moral psychology and account of character; legal theorists engage his notion of natural law; and philosophers of religion revisit his arguments for God’s existence and doctrine of analogy.
15.2 Institutional and Educational Legacy
His works became staples in university and seminary curricula for centuries. Manuals and commentaries derived from his texts structured Catholic education well into the twentieth century. Even where explicit Thomist formation has waned, the categories he helped consolidate—such as substance and accident, nature and grace, faith and reason—remain embedded in theological and philosophical discourse.
15.3 Cross-Tradition and Secular Reception
Beyond Catholicism, Aquinas has influenced Protestant scholasticism, some strands of Orthodox theology, and secular natural law theory. Modern courts and political theorists occasionally reference Thomistic ideas about the common good and justice, often mediated through later natural law traditions.
At the same time, critics from Enlightenment, existentialist, and postmodern perspectives have challenged the universality of his metaphysical assumptions and the hierarchical, teleological worldview they express.
15.4 Ongoing Debates About His Relevance
Current scholarship is divided on how to assess Aquinas’s contemporary significance:
- Some regard him as a perennial philosopher whose synthesis offers enduring insights for metaphysics, ethics, and public reason.
- Others view him primarily as a historically important medieval theologian whose framework must be significantly reinterpreted or bracketed in modern contexts.
Nevertheless, his corpus remains a central point of reference in discussions about the relationship between reason and revelation, the grounding of moral norms, the nature of law and political authority, and the philosophical articulation of classical theism.
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@online{philopedia_thomas_aquinas,
title = {Thomas Aquinas},
author = {Philopedia},
year = {2025},
url = {https://philopedia.com/philosophers/thomas-aquinas/},
urldate = {December 10, 2025}
}Note: This entry was last updated on 2025-12-08. For the most current version, always check the online entry.
Study Guide
intermediateThe biography is conceptually dense and assumes some familiarity with medieval thought and basic metaphysics, but it is structured and explanatory enough for motivated readers who are not specialists.
- Basic outline of medieval European history (Church, papacy, Holy Roman Empire) — Aquinas’s life and work are tightly linked to thirteenth‑century conflicts between popes and emperors, the rise of universities, and new religious orders.
- Introductory understanding of Aristotle (substance, form/matter, causes) — Aquinas’s metaphysics, ethics, and theology presuppose Aristotelian concepts, which he adapts rather than explains from scratch.
- Familiarity with core Christian beliefs (Trinity, creation, grace, salvation) — The biography frequently references Aquinas’s theological positions and church debates that assume knowledge of basic Christian doctrine.
- General idea of what a university and scholastic disputation are — Much of Aquinas’s career took place in medieval universities using the scholastic method, which shapes both his writing style and intellectual goals.
- Aristotle — Helps you see which ideas Aquinas is borrowing and transforming, especially in metaphysics, ethics, and logic.
- Scholasticism — Provides background on the university culture, methods, and genres (commentaries, disputed questions) that frame Aquinas’s work.
- The Natural Law Tradition — Clarifies the broader history of natural law theory so you can situate Aquinas’s account of law and moral norms within a longer trajectory.
- 1
Get oriented to Aquinas’s life, context, and why he matters before tackling technical doctrines.
Resource: Sections 1–4: Introduction; Life and Historical Context; Education, Dominican Vocation, and Early Influences; Academic Career in Paris and Italy
⏱ 60–90 minutes
- 2
Survey his writings and how he thinks, to understand the forms and methods in which his ideas appear.
Resource: Sections 5–6: Major Works and Literary Corpus; Philosophical Method and Scholastic Style
⏱ 45–60 minutes
- 3
Study his metaphysics and doctrine of God as the backbone of his system.
Resource: Sections 7–8: Metaphysics: Being, Essence, and Existence; Theology of God: Attributes, Trinity, and Creation
⏱ 90–120 minutes
- 4
Focus on his account of the human person, knowledge, ethics, and ultimate happiness.
Resource: Sections 9–10: Human Nature and Knowledge; Ethics, Virtue, and the Beatific Vision
⏱ 90–120 minutes
- 5
Explore his political and legal theory and his treatment of faith and reason, which connect his metaphysics and ethics to public life and theology.
Resource: Sections 11–12: Law, Politics, and the Common Good; Faith, Reason, and the Preambles of Faith
⏱ 60–90 minutes
- 6
Consolidate your understanding by seeing how Aquinas was received, reinterpreted, and contested, and reflect on his continuing significance.
Resource: Sections 13–15: Reception, Condemnations, and Canonization; Thomism, Neo-Thomism, and Modern Interpretations; Legacy and Historical Significance
⏱ 60–90 minutes
Scholastic Method (quaestio disputata)
A structured format for inquiry that presents a question, articulates objections, cites an authoritative counter‑position, offers a reasoned solution, and replies to each objection.
Why essential: Understanding this method is crucial for reading Aquinas’s works (especially the Summae and disputed questions) and for seeing how he integrates opposing views into a larger synthesis.
Act and Potency (actus et potentia)
A metaphysical pair where ‘act’ is a realized state and ‘potency’ is a real capacity for being otherwise, used to explain change, composition, and the difference between God and creatures.
Why essential: Aquinas’s accounts of change, causality, and divine perfection all presuppose this distinction; it underlies his doctrine of God as pure act and creatures as composites of act and potency.
Essence and Existence (essentia et esse)
In creatures, essence (what a thing is) and existence (that it is) are really distinct and composed; in God they are identical, so God is subsistent being itself (ipsum esse subsistens).
Why essential: This distinction is central to Aquinas’s metaphysics and his understanding of dependence on God; it informs his view of participation, causality, and the difference between Creator and creature.
Analogy of Being (analogia entis)
The view that terms like ‘being’ and ‘good’ apply to God and creatures neither in exactly the same sense nor in totally different senses, but analogically, according to ordered likeness within greater unlikeness.
Why essential: Analogy explains how we can speak meaningfully yet non‑literally about God, and it structures his approach to theological language and natural theology throughout the biography.
Natural Law (lex naturalis) and Eternal Law (lex aeterna)
Eternal law is God’s rational ordering of the universe; natural law is the participation of rational creatures in this order, expressed in basic moral principles knowable by reason.
Why essential: These concepts ground Aquinas’s ethics, political theory, and definition of law as an ordinance of reason for the common good, making them key to Sections 10–11 and to his broader legacy.
Beatific Vision (visio beatifica)
The direct, intuitive vision of God’s essence granted in the next life, which alone fully satisfies the human desire for happiness.
Why essential: This is the organizing end of Aquinas’s theology and ethics; many elements of his psychology, virtue theory, and grace are intelligible only when seen as ordered to the beatific vision.
Primary and Secondary Causes
God as primary cause gives being and efficacy to created causes, which act as genuine secondary causes within their own order, without competing with divine causality.
Why essential: This framework is vital for grasping Aquinas’s views on providence, freedom, nature, and miracles, and for understanding later debates about determinism and divine action.
Faith and Reason (fides et ratio) and the Preambles of Faith
Faith accepts revealed truths on God’s authority; reason discovers truths accessible to natural inquiry. Preambles of faith are truths (like God’s existence) knowable by reason but also revealed.
Why essential: This conceptual pair structures Aquinas’s place in university theology, his use of Aristotle and non‑Christian sources, and his influence on later discussions of natural theology and public reason.
Aquinas simply repeats Aristotle with a Christian veneer.
While Aquinas adopts many Aristotelian concepts, he significantly reshapes them—for example by insisting on a real distinction between essence and existence, by integrating Neoplatonic participation, and by orienting all philosophy toward the beatific vision.
Source of confusion: Because he often writes in commentary form and uses Aristotelian terminology, it is easy to overlook his critical departures and the theological aims that inform his metaphysics.
Scholastic method is purely authoritarian, just quoting earlier authorities instead of reasoning.
Aquinas relies on authorities but systematically distinguishes demonstrative arguments from arguments from authority, and his quaestio method requires him to present and answer strong objections using reasoned analysis.
Source of confusion: Modern readers can be distracted by the prominence of citations and miss the logical structure of the respondeo and the role of objections in sharpening his own positions.
Aquinas’s ethics leaves no room for emotions; virtue means suppressing passions.
Aquinas holds that passions are natural and can be rightly ordered by reason and virtue; well‑formed emotions actually support virtuous action rather than being enemies of morality.
Source of confusion: The technical language of ‘passions’ and ‘appetites’ and the influence of later moralistic readings can make his more integrated view of emotion easy to miss.
Natural law in Aquinas is a rigid, culture‑blind moral code.
Aquinas distinguishes universal first principles of natural law from their variable applications; he explicitly allows for diversity in human laws and customs so long as they serve the common good and do not contradict basic moral precepts.
Source of confusion: Later natural law traditions sometimes presented simplified moral manuals that are then retrojected onto Aquinas, obscuring his more nuanced account of specification and exception cases (e.g., extreme need and property).
Aquinas’s God is so simple and immutable as to be impersonal and unrelated to the world.
Although Aquinas stresses divine simplicity and immutability, he also affirms God’s knowledge, will, and love, and describes creation and providence as expressions of divine goodness and care.
Source of confusion: The highly metaphysical language around simplicity and pure act can sound abstract and distant, especially when detached from his treatments of Trinity, Incarnation, and providence that connect God to history and relationship.
How did the rise of universities and mendicant orders shape Aquinas’s intellectual development and the genres in which he wrote?
Hints: Look at Sections 2–4 and 5. Consider his roles in Paris and Italian studia, the disputes over mendicants, and the institutional needs that produced commentaries, Sentences lectures, and disputed questions.
In what ways does Aquinas’s distinction between essence and existence influence his understanding of God as ipsum esse subsistens and of creatures as participating in being?
Hints: Use Section 7 on metaphysics and Section 8 on the theology of God. Ask how the real distinction in creatures contrasts with divine simplicity, and how this grounds participation and analogy of being.
How does Aquinas reconcile strong divine providence and primary causality with genuine human freedom and secondary causes?
Hints: Draw on Sections 7.4, 8.4, 9.3, and 10.3. Identify what each kind of cause does, and how Aquinas thinks God’s universal causality operates ‘in’ rather than ‘instead of’ created actions.
Compare Aquinas’s account of happiness and the beatific vision with Aristotle’s ideal of contemplative life. In what respects is Aquinas continuing Aristotelian eudaimonism, and in what respects transforming it?
Hints: Focus on Section 10.1 and 10.5, along with earlier notes on Aristotelian ethics in Sections 3 and 7. Consider the role of grace, supernatural end, and the vision of God versus contemplation of highest created causes.
What is the role of natural law in mediating between eternal law and human positive law in Aquinas’s political theory?
Hints: Use Section 11.1–11.3. Map the fourfold scheme of law, then explain how natural law both grounds and limits human legislation, especially in relation to the common good.
To what extent does Aquinas’s distinction between faith and reason, and his notion of ‘preambles of faith’, provide a viable model for contemporary discussions about religion in public life?
Hints: Refer to Section 12.1–12.4 and Section 14.3–14.4. Ask how his separation and cooperation of disciplines might translate (or fail to translate) into a pluralistic, secular context.
How did later Thomist and Neo‑Thomist movements reshape Aquinas’s thought, and what are some risks and benefits of reading Aquinas through these later schools?
Hints: Look at Section 14.1–14.3 and Section 13.3. Identify key Thomist commentators and Neo‑Thomist strands, then consider where they clarify Aquinas and where they may systematize him in ways that differ from the 13th‑century context.