CLEMENT (150-215)
Clement of Alexandria was a Christian philosopher and teacher. Along with Origen and Augustine, he was an important figure of the Patristic philosophy that prevailed in the 2nd-8th centuries. Clement believed that philosophy until that day prepared people for religion. In his work Stromata (Mixed Notes), he made a comprehensive review of Christian doctrine.
ORIGENES (185-254)
Origen of Alexandria was a Christian philosopher and teacher. In his book Hexapla, he compared different Greek versions of the Old Testament, and in his book De Principiis, he explained the principles of Christian theology. He thought that the holy book should be interpreted on three different levels; the historical message was the first level, which contained historical information, the moral message was the second level, and the allegorical level (Divine message) was the last level to be followed in the interpretation of the Bible. According to a Platonic and Neo-Platonic interpretation of the Father, Son and Holy Spirit trinity, the Father was the absolute reality, the Son God was the savior shepherd and the highest priest. The Holy Spirit brought spiritual gifts to people. Jesus Christ also worked on the human soul and salvation.
AUGUSTINUS (354-430);
He was born in today's Algeria, and was educated in Carthage and Milan. The Confessions he wrote after accepting Christianity is considered a classic of Christian theology. He served as a priest and bishop in Hippo, Algeria, and was known as Augustine of Hippo.
According to Augustine, who said, "You will not understand unless you believe!", knowing should come after believing. God is a Creator. He created the universe from nothing with his mind and free will. God illuminates all people with his spiritual light.
Love holds everything together and directs it towards God. Those who direct their love to God establish the State of God, those who direct their love to the world establish the World State. We must live as one of God's chosen ones with our free will. God knows exactly how people choose their destiny.
BOETHIUS (480-524)
He was born and lived in Rome. He served as a consul. He was tried for treason. He wrote “On the Consolation of Philosophy” in prison with the help of poetic muses and muses. He translated Aristotle’s books into Latin and wrote a book of logic himself. His book De Trinitate is about the doctrine of the Holy Trinity. He also has a work explaining the mathematical foundations of music. According to Boethius, who tried to reconcile Plato and Aristotle, God is pure form. The concepts we have from birth were formed in our previous lives. The faculty of understanding belonging to the mind is a divine faculty that can grasp the idea.
ERUIGENA (815-877)
Irish theologian philosopher Erigena translated the works of philosophers from ancient Greek to Latin and wrote commentaries. He made a synthesis of Christian theology and neoplatonism. There should be a unity between philosophy and theology. He was also interested in music and medicine, and taught liberal arts.
He divided existence into four categories: uncreated but creating nature (God), created and creating nature (divine ideas), created and non-creating nature (sensory world), uncreated and non-creating nature (return to God).
God is without beginning and cause in time. Due to his otherness, he cannot be described. Positive theology; qualities such as goodness, mercy, truth, wisdom are also attributed to God either symbolically or metaphorically. Negative theology; even if we use the highest levels of human qualities, it is impossible for us to make any description or definition about God.
While man was a divine being, he had to take on the characteristics of the animal level after committing sin. The world was created for man.
ANSELMUS (1033-1109)
Anselm, of Italian origin, took the title of the second Augustine, thinking that in order to understand, one must first believe. He essentially has Platonic views. God is that than which nothing greater can be thought, and by this definition he must exist in reality (Ontological argument). He is considered the “Father of Scholasticism”. The source of knowledge is reason and faith. Freedom is the power of the will to pursue truth for the sake of truth.
ABELARDUS (1079-1142)
Born and living in France, Abelardus wrote on the fields of logic, theology and ethics. Abelardus says that we have an abstraction faculty that we can call our senses and understanding. General concepts are constructed through abstraction. Abstraction is focusing on a certain feature of something and ignoring its other features. According to him, universals are names that have a sign function.
Sin is knowingly and willingly disobeying God's commands. Individual intention is the only criterion of morality. This is incompatible with the common sin doctrine of Christianity. Abelardus was judged for his thoughts that were more advanced compared to his era.
THOMAS AQUINAS (1225-1274)
Italian Thomas Aquinas tried to make a synthesis of Aristotle's thoughts with Christian theology. He deals with all the subjects of theology in Summa Theologica.
God is pure act. There is no movement or change in him. Man is a composite structure consisting of soul and body. The soul is created in the image and likeness of the creator. God is the creator, man is the producer. Being comes into being through participation (methexis). The necessary being remains what it is, it cannot exist in any other way, and that is God.
Thomas Aquinas' "Cosmological Argument of God", also known as the five ways; he is the first mover, the first effective cause, the one who gives necessity to everything, the cause of beings and the cause of the perfections of beings, the final cause and purpose.
Faith is above reason, but reason does not contradict faith. Some truths that come through revelation can only be understood through faith. Reason does not have any object by birth, but the active reason shares in the light of divine reason.
Will naturally directs man towards what is good. In order to live a good life, man must act in accordance with virtue and provide the material needs necessary for a virtuous action.
ROGERUS BACO (1214-1292)
An English scientist and philosopher, Baco (Roger Bacon), addresses scientific method, experimental research, mathematics, natural sciences and metaphysics in his famous work "Opus Majus". He emphasized the need to increase the accuracy of scientific knowledge and defended experimental methods and observation. The most fundamental science is mathematics. He criticized the dogmatic approach of the church and advocated the need for a balance between science and theology. The belief of many people that something is true should be met with skepticism. The opinion of the majority cannot be a guide on the path to wisdom. He is considered the pioneer of the modern scientific method. He worked in the fields of chemistry and optics. Rogerus Baco's ideal of Christianity is a society of people united around faith and governed by a single person.
BONAVENTURA (1221-1274)
Giovanni Fidenza Bonaventura, a Franciscan priest born in Italy, is known for his Christian theology and mysticism. The Journey to God is his most famous work. Reaching God is possible not with the mind but with the heart and spiritual experience. The human being is a combination of body and soul. The soul's purpose is to reach the most perfect good in order to ensure its own happiness.
Bonaventura's theory of four lights is as follows: external light illuminates arts and crafts, lower light activates sense perception, inner light illuminates mental truths, and the fourth light illuminates higher truths.
Knowledge of objects is obtained by the mind in an abstract way. In order to fill the tabula rasa (table on which nothing is written), the soul abstracts the intelligible contents of sensible objects. In this way, the mind reaches universals and first principles. There are four divine virtues that will provide divine enlightenment: supreme honesty (justice), stability of being (steadfastness), practical wisdom (most important, prudence) and purity (temperance). God strengthened the soul through these four virtues.
ALBERTUS MAGNUS (1200-1280)
Born in Germany, Albertus Magnus tried to combine Aristotle's philosophy with Christian theology, and made extensive research on plants, minerals and animals in natural sciences. According to Magnus, active intellects are derived from the intellect of God. Passive intellect accepts knowledge. Speaking about God as the first being is metaphysics, while speaking about God known through faith is theology.
SIGERUS DE BRABANT (1240-1282)
Born in what is today Belgium, Sigerus de Brabant worked to combine Aristotelian philosophy with Christian theology. In his thoughts, he examined the relationship between natural intellect and theological belief. He argued that philosophical reasoning should support theology.
Contingent events are not the product of necessary causes. God knows that He is the remote cause of all things, but He does not know future contingent events.
The conclusion reached by reason, “Man is not a created being,” must certainly be rejected outright by faith.
BOETHIUS DACUS (1200s)
The birth and death dates of the Danish Dacus are unknown. He blended Aristotle's ethical thoughts with Christian theology.
According to him, the proposition that the world was created by a will cannot be explained by science. Science must be shaped in the context of rational principles. Propositions related to natural philosophy and propositions that fall within the scope of faith will be true even if they contradict each other as long as they remain in their own fields.
IOHANNES DUNS SCOTUS (1265-1307)
The Scottish Franciscan philosopher had an Aristotelian understanding of knowledge. Our knowledge is obtained through first principles, deductions from them, our sense experiences and our own actions (sensing, imagining, understanding).
Existing things must have been produced by something else. From here we arrive at the existence of a first efficient cause, which is God. Duns Scotus believed that this proof was a posteriori (after experience, derived from experience), a synthetic judgment.
GUILLELMUS DE OCKHAM (1285-1347)
This English philosopher and theologian studied at the University of Paris and became a member of the Franciscan Order. According to his principle known as the Sword of Ockham, unnecessary assumptions should be avoided and the simplest explanation should be preferred. He argues that general concepts only exist in the mind and do not have an independent existence in the real world, in other words, he has a Nominalist approach. These concepts explain things and point to them.
God's will is over everything, but we cannot directly experience God's effects on earth, it is only possible to reach some information about Him by using some of His divine attributes.
NICOLAUS CUSANUS (1401-1464)
The first book of German philosopher, mathematician and philosopher Cusanus' work "De Docta Ignorantia" is about God, the second book is about the universe that emerged with God's self-disclosure, and the third book is about Jesus and theology. According to Cusanus, man is a microcosm. Man, created in the image of God (imago Dei), contains both matter, organic and animal life, and rationality. Man must be aware that he knows nothing. God is an entity that cannot be grasped by our minds. We know something positive about Him as the Creator, and through these, we can open the door to God.
Cusanus was interested in mathematical and astronomical studies. In particular, the theories he developed on the concept of infinity, the infinity of the circle, and its properties are considered an important step in the development of mathematical thought.
FRANCISCO SUAREZ (1548-1617)
Spanish scholastic philosopher and theologian Francisco Suarez provides a comprehensive analysis of theological and philosophical debates in his book De Controversiis. He examines many metaphysical and philosophical concepts in detail in his book Metaphysical Disputations. God is the only being whose essence is to exist. God, who produces and creates, is not produced or created.
Natural law is established by will in the nature that God has placed in man. It imposes responsibility on man. Natural law and rational nature are identical. It is the duty of the will to ensure that man progresses and moves towards a certain goal. Human will has a share of the divine will.