History of Philosophy

Philosophy of The Middle Ages

Philosophy of the 12th–13th Centuries

The 12th century gave rise to the philosophies of Peter Abelard and the mystics. Peter Abelard (1079—1142), a French philosopher, is remembered both for the originality of his philosophical views and the controversial nature of his character. Abelard's philosophy addressed several topics of importance in the philosophy of his time:

• In the debate over universals, Abelard was a conceptualist.
• On the relation between faith and reason, Abelard took a position of strict rationalism. Anything that is an object of faith must be rationally proven. One cannot believe in something one does not understand; for him, faith was the acceptance of knowledge that had been comprehended.
• Concerning the attributes of God, Abelard asserted that God’s three main attributes were power, wisdom, and goodness, which he identified with the persons of the Trinity. All these attributes manifest in creation: God creates because He is powerful, wise, and good.
• Abelard denied the uniqueness of Christian ethics, asserting that the Christian moral code was nothing more than the articulation of natural law. God implanted moral law within the fabric of creation, and this law is expressed in religion. Thus, Christian morality is merely a particular expression of universal morality.
• Abelard believed that God had created the best possible world, but original sin introduced evil into it. Unlike Augustine, who regarded original sin as a universal characteristic of humanity, Abelard—being a conceptualist in the debate on universals—could not agree that original sin was an inherent feature of humankind. He held that Adam and Eve, through their sin, only spread evil to their descendants in the sense that they provided a bad example, which others learned to follow.

The 12th century also saw the rise of another significant philosophical trend: mysticism. The mystical tradition of Western Christianity was rooted in the spiritual legacy of Saint Benedict of Nursia (c.480—547), who established the first monastic rule in the West. A group of thinkers in the 12th century sought to interpret the principles of spiritual life described by Saint Benedict, thereby laying the foundation for medieval philosophical mysticism.

• The founder of medieval philosophical mysticism was Bernard of Clairvaux (1091—1153), a prominent figure in medieval culture. He began his reflections with the 12 degrees of humility described by Saint Benedict in his monastic rule: always remembering the fear of God; renunciation of one’s desires; obedience to superiors; enduring difficulties with dignity in obedience; humbly confessing one’s sins; being content with the least and worst; being convinced of one’s own unworthiness; refraining from any action forbidden by monastic rules; practicing silence and refraining from unnecessary speech; abstaining from laughter; speaking without levity, criticism, or pride; and expressing humility not only in heart but in behavior. Bernard interpreted these steps as preparation for spiritual life. By humbling oneself, a Christian becomes aware of their own spiritual poverty, and in this light, recognizes the poverty of others. This understanding of others engenders not condemnation, but compassion. Compassion is the purification of the heart, which is essential for knowing God. Bernard emphasized that God cannot be known through reason; one can only experience a mystical encounter with Him.
• Hugh of Saint-Victor (1096—1141) asked whether humans could know God through reason. He believed that God had created the world and humanity in such a way that humans cannot know God by reason alone, but neither is knowledge of God possible without reason. If God could be known purely through reason, everyone would believe in Him, since everyone possesses reason, and faith would not be a spiritual achievement. Conversely, if God could be known without reason, religion would devolve into irrational superstition. Therefore, knowing God is the result of both reason and faith in Revelation. Hugh developed a philosophical theory of knowledge, which he saw as progressing through three stages: perception (where one perceives both internal and external experiences), reason (where one seeks answers to questions like “what?”, “why?”, and “for what purpose?”), and intellect (where one penetrates the deeper meanings). The third level of knowledge requires illumination from divine light and deep faith. To achieve illumination, one must prepare the soul through moral refinement. While God created all people capable of intellectual contemplation, original sin limited this capacity. Now, intellectual contemplation can only be attained through strenuous spiritual and moral effort. Hugh led the Abbey of Saint-Victor in Paris, and under his direction, the school there became one of the most prominent educational centers of 12th-century Europe. Thanks to Hugh and his followers, the Saint-Victor school grew into a beacon of European education, and Paris gained a reputation for scholarship that it maintains to this day. The tradition of the Saint-Victor school continued with the establishment of the Sorbonne.
• The next major figure of the school was Richard of Saint-Victor (c.1110—1173). Richard built upon Hugh's ideas. If the main faculties of the soul are will and reason, then both must participate in the process of knowing. For truth to be known, the will must first attain moral perfection, after which reason can proceed with the task of knowledge. Contemplation of truth progresses through three stages. The first is the illumination of the intellect, enabling it to see beyond the limits of reason. The second is a further illumination, raising the intellect to a level beyond ordinary contemplation. The third is the ultimate illumination, where the intellect encounters God directly, an experience that defies any expression in words. According to Richard, while the mystic must prepare for illumination, the encounter itself is a gift from God, bestowed according to His will, not the mystic’s merits.
• After Richard, the Saint-Victor school did not produce original thinkers. The succeeding generations expanded upon the teachings of their predecessors and focused on improving the system of education. This school remained the leading educational center of 12th-century Europe, with its graduates spreading across the continent to develop educational systems in various countries.

By the 12th century, the works of Aristotle were little known to European scholars. Yet, among Arab philosophers, interest in Aristotle was immense. In the 13th century, through the influence of Spanish Arabs and Jews, Aristotle's works reached Catholic universities, sparking a wave of enthusiasm among European philosophers. From this point on, Aristotle's philosophy became the foundation of Western European philosophical discourse. Aristotle’s influence grew so dominant that in many texts of the time, he was referred to simply as "The Philosopher," with no need to specify his name—everyone understood that Aristotle was meant. However, his ideas required interpretation. The question of how exactly Aristotle should be understood became the central theme of philosophical debates of the era. These discussions were so lively that the 13th century is considered the golden age of scholasticism.

In Western European scholasticism, Aristotelianism developed within three main schools: Latin Averroism, the Dominican school, and the Franciscan school. Along with Aristotle’s texts, commentaries on his works by Arab thinkers, especially Averroes, were also introduced to Europe. While Aristotle himself became an unassailable authority for 13th-century European philosophy, his Arab commentators, particularly Averroes, were received with more ambivalence. Latin Averroism was a movement within 13th-century European philosophy whose followers interpreted Aristotle’s thought in light of Averroes. The University of Paris became the major center of medieval Averroism, with Siger of Brabant (1235/1240—1284) as its leading figure.

A central concern in Siger's reflections was his proof of God's existence. He held that the existence of God was an indisputable fact, one that could not be doubted. Everything that exists, he argued, has a cause; thus, there must be a cause for all things. Siger called this the "ens causans tantum non causatum" (a being that causes but is not caused). This, he identified as God, the cause of all that exists but who requires no cause for Himself. Moreover, Siger formulated several theses that largely echoed Averroes:

• The intellect of all people is one and the same; every individual, in the process of learning, partakes in the universal human intellect.
• There is no individual knowledge; when a person seems to know something, they are in fact merely receiving knowledge from the universal intellect.
• Humans do not have free will; they choose and desire out of necessity.
• Everything that occurs on Earth is subject to celestial bodies; in this, Siger justified astrology.
• The world is eternal: if God is pure act, that is, an absolutely unchanging essence, and at the same time is the Creator, He must always be the Creator.
• Humanity has always existed, and there was never a first human.
• If the soul is the form of the body, and form ceases to exist when the substance is destroyed, then the soul dies at the moment of bodily death.
• If the soul is mortal, it will not suffer in hell.
• Free will is only a passive capacity in humans, enabling them to perceive necessity rather than actively making decisions.
• God does not know or concern Himself with individual things; He only produces His thoughts, which are general universals.
• God knows nothing distinct from Himself.
• The world is governed not by Divine Providence but by necessity.
• God cannot bestow immortality upon a mortal thing.

Siger’s teachings were in stark opposition to Catholic doctrine, and they also contradicted the ideas of Aristotle himself. Averroes had interpreted Aristotle with considerable freedom, and Siger had distanced himself even further from pure Aristotelian thought. Siger’s views were declared heretical, marking the end of Latin Averroism. Nevertheless, interest in Aristotelianism did not wane, and other schools continued to develop it.

The Dominican school was represented by monks of the Order of Saint Dominic, who fostered some of the most influential philosophers of the High Middle Ages, whose impact is still felt today. Among them was Albert the Great (1193—1280), known for his vast knowledge, earning him the title Doctor Universalis. His views can be summarized in the following key points:

• The relationship between philosophy and theology: There are profound differences between these fields of knowledge. Theology is based on revelation, has a practical goal—to lead people to holiness—and studies God as the object of spiritual experience. Philosophy, on the other hand, is based on reason, has a theoretical goal—to increase knowledge—and studies God solely as the highest being in itself.
• The relationship between faith and knowledge: Faith precedes knowledge because a person can only know what they believe in.
• The principles of being: The existence of a substance is determined by two principles—matter and form. In his interpretation of these principles, Albert followed Aristotle.
• The knowledge of God: The human mind cannot comprehend what God is, but it can know the fact of His existence. Everything in the world stands in a relationship of super- and subordination, where the cause is superior to its effect, and the effect is subordinate to its cause. If the cause is more perfect than the effect, then tracing the chain of causes will eventually lead to the most perfect being, which is superior to all that exists. This cause is the first being, from which everything else derives.
• God is reason: If God is the Creator of the world, then He produces the forms of things in the world. From this argument, Albert characterized God as the "

intellectus universaliter agens (the universally active intellect). He is universal because He produces all forms, and active because He is the creator of these forms.

• God is absolute will: Will has three meanings: it is the rational desire for something one lacks but wishes to possess; it is the satisfaction from the good one already has; and it is the force of spirit driving one to action. God cannot be will in the first sense, but He can be in the second and third.
• God is absolute power: Albert derived this attribute from the fact that God created the world. If He was able to create it, then He must be absolute power.
• The human soul: Not only God but also man possesses reason, will, and power. While God possesses these attributes in absolute perfection, in man they are imperfect. These three human attributes are unique in that no physical organ in the human body produces them. This implies they are not located in the material aspect of the human being. The aspect of a person that contains reason, will, and power, Albert called the soul.

In these reflections, Albert the Great reconciled the philosophical teachings of Aristotle with the theological doctrines of Christianity, striving to create a harmonious synthesis between faith and reason. While remaining faithful to the principles of Christian theology, Albert also acknowledged the immense intellectual legacy of Aristotle and sought to integrate it into the framework of medieval scholastic thought. Thus, Aristotelianism, as interpreted by the Dominican school, became a vital force in shaping the intellectual landscape of medieval Europe and laid the foundation for further philosophical and theological development in the centuries to come.

The philosophy of Albert the Great represents the first large-scale and successful attempt to expound Christian doctrine in the language of Aristotle’s philosophy. Albert’s disciple was St. Thomas Aquinas (1225—1274), the greatest thinker of the High Middle Ages. Thomas articulated several important ideas:

• Truth: Thomas opposed the Latin Averroists, who believed in two truths: a philosophical truth accessible only to intellectuals, and a religious truth, a simplified version of the philosophical one intended for the masses. Thomas argued that since the world has one Creator, truth must also be one. The difference between truths is not in their content but in the method of understanding. Thomas distinguished between natural and supernatural truths. He called natural those aspects of truth that can be known through nature, while supernatural truth is that which is revealed in Revelation. Yet their content remains unified.
• Metaphysics: Thomas adopted Aristotle’s metaphysical doctrines concerning substance, form and matter, actuality and potentiality, essence and existence, and developed them by adapting them to the philosophy of his time. For this reason, alongside Aristotle, Thomas can be regarded as a founder of classical metaphysics.
• Theory of Knowledge: Knowledge is possible because the subject and object of knowledge, in a certain sense, acquire the same form—that is, the knowing subject takes on the form of the object. The intellect understands only what it receives from the senses; thus, sensory knowledge is primary. There are no innate or a priori ideas; all knowledge that a person can have is derived solely from experience. According to Thomas, knowledge is realized in several stages:

✵ Senses (sensus), which perceive empirical data,

✵ Active intellect (intellectus agens), which receives data from the senses, processes them, and forms general concepts,

✵ Passive intellect (intellectus possibilis), which retains the concepts formed by the active intellect and applies them to subsequent objects of the same class.

• Theology: There are three ways to know God:

✵ Direct knowledge, which will only become accessible to a person after death when they meet God;

✵ Knowledge through faith, that is, knowing God through revelation;

✵ Knowledge through reason, to which Thomas devoted the most attention. Human reason can know the fact of God’s existence—that is, that God is—but can only partially know His attributes.

• Thomas formulated five proofs of God’s existence (quinque viae):

✵ The argument from motion: Since everything that moves has a cause for its movement, there

must be a first cause of all movement, which initiates motion but remains unmoved. This unmoved mover is God.

• The argument from causality: Everything that exists has a cause for its existence. The chain of causes cannot be infinite, so there must be a first cause of all being. This first cause is God.
• The argument from contingency: All things that exist can either exist or not exist, meaning they are contingent. For contingent things to exist, there must be a necessary being that is the source of their existence. This necessary being is God.
• The argument from degrees of perfection: Every entity has varying degrees of perfection. Therefore, there must be something that possesses the highest degree of perfection. The most perfect being is God.
• The argument from the governance of the world: The universe operates according to laws and order, not randomness. Therefore, there must be a purpose behind this order, which guides everything toward its end. This purpose is God.
• The relationship between essence and existence in God: Thomas made a clear distinction between essence and existence in all created beings. Everything that exists has some essence, but essence can be conceived apart from existence. Only in God are essence and existence inseparably united, because God's essence is His existence.
• Anthropology: In his views on human nature, Thomas followed Aristotle and Albert. He claimed that the defining characteristics of humans are intellect and will, but humans do not possess a physical organ containing these attributes. Therefore, intellect and will must belong to the non-corporeal part of humans—the soul.
• Ethics: Thomas based his ethics on Aristotle’s fundamental thesis that all beings strive for perfection. Humans are no exception; they too seek perfection. The highest perfection is God. Thus, to strive for perfection means to strive for God, who is the ultimate goal of all existence. Approaching God makes a person happy. Therefore, in the ethical context, perfection and happiness are synonymous. Perfection is achieved through adherence to Divine Law, which manifests in conscience and natural law. The goal of moral action is the attainment of virtue. Thomas divided virtues into two groups:

✵ Moral or cardinal virtues, which he adopted from Plato (wisdom, justice, courage, and temperance),

✵ Theological virtues (faith, hope, and charity).

In this grand synthesis of Aristotelian philosophy and Christian doctrine, Thomas Aquinas built a system of thought that would profoundly shape the course of medieval and subsequent philosophy, providing a lasting foundation for both metaphysical inquiry and theological reflection.

Another significant philosophical movement of the 13th century was the Franciscan school, consisting of philosophers and theologians who belonged to the monasteries of the Order of St. Francis. The roots of this school trace back to the Franciscan traditions of the 12th century.

• Saint Bonaventure (1221—1274), who studied in Paris, embraced the teachings of the School of St. Victor. Bonaventure focused on the study of spiritual contemplation and its classification into stages. He held that knowledge begins with experience, and there is no other source of understanding. Contemplation consists of three stages: the contemplation of material bodies, the contemplation of one’s own spiritual essence, and the contemplation of God Himself. At first, the mystic contemplates God through His creation; afterward, he plunges into his own soul, where he contemplates the Image of God imprinted therein. Only then can he ascend to the contemplation of God. At this level, the mystic enters into ecstasy—a state in which the senses and intellect are suspended, and the spirit transcends both being and non-being, knowledge and ignorance, attaining an absolutely supernatural knowledge. Continuing the mystical tradition of the School of St. Victor, Bonaventure asserted that it is possible to contemplate God not only after death but also in earthly life. However, this becomes only partially possible through mystical experience.
• Roger Bacon (c. 1214—1292) expressed skepticism toward rational speculations, arguing that theories formed solely through logical constructions are uncertain and unconvincing. For Bacon, experience was the highest and most perfect source of knowledge. To gain knowledge of natural processes, Bacon employed experimentation. He also understood that the systematization of experimental results required mathematics. Bacon used mathematical calculations to plan experiments and describe their outcomes. His focus was more on the practical application of his empirical theory than its theoretical description; he conducted numerous experiments, described them, and compared their results. Experience, for Bacon, was valuable not only in natural science but also in spiritual life. Like Bonaventure, he was a mystic. Bacon was convinced that contemplation plays only a small role in spiritual life; spirituality is realized through mystical experience. There is little point in talking much about God—one must have the living experience of encountering Him. Thus, the core category of Roger Bacon’s philosophy is experience, which he considered the principal method for acquiring both natural and mystical knowledge.
• John Duns Scotus (c. 1266—1308) was the greatest thinker of the Franciscan school and, at the same time, the main opponent of Thomas Aquinas.

✵ Like Aristotle and Aquinas, Duns Scotus believed that knowledge begins with sensory experience. However, Scotus held that experience alone is insufficient for the formation of knowledge. There must be internal faculties in humans that enable the perception and processing of experiential data. He called this faculty intellect. However, they serve different functions: experience reveals material things, while the intellect strives to reach immaterial principles. Yet there are elements of intellect that a person never perceives through experience, but which nonetheless determine the course of cognition, such as the laws of logic.

✵ Aquinas held that the principles present in the material world are also present in God. For instance, if the things of the world are good and they were created by God, then God Himself is good. Scotus, on the other hand, argued that the words people use to describe material things are ambiguous and, therefore, cannot be used to describe God without the risk of error. In this way, Duns Scotus initiated a discussion about the role of language in knowledge and the structure of the world—a question that would later become central in the philosophy of language.

✵ Like every medieval philosopher, Scotus could not ignore the problem of universals. Like Aristotle and Aquinas, he believed that universals exist in reality, but he interpreted them in his own way. He emphasized individual things. Universals are primarily present in things, not outside them. The human mind extracts them from things, forming general concepts.

✵ A key aspect of Duns Scotus's philosophy is his doctrine of the will. Here, he opposed Aquinas. For Aquinas, reason is the primary faculty of a person, while the will is secondary, since a person cannot desire something they do not know. Scotus, drawing on Augustine and Anselm, held that God endowed humanity with free will. If the will is free, this means that nothing, not even reason, can limit it. The will is primary in the process of cognition, for a person will not engage in knowing something that does not interest them. At any given moment, the senses perceive vast amounts of information, but a person focuses only on what interests them—on what their will inclines toward. The will is not only the defining feature of a person but also of God. God does whatever He wills; He is not bound by any laws.

✵ The foundational axiom of Duns Scotus’s ethics is love. A person is called to love God—this is a self-evident truth for the philosopher and forms the basis of all further reasoning. Since God acts solely according to His will, the foundation of ethics lies primarily in God’s will. God established the laws He desired, and because He chose to establish such laws for humanity, they are the best for humanity. In respecting human free will, God does not compel people to follow His laws. According to Scotus, moral laws cannot be justified by reason, as they stem not from reason but from God's will.