St. Thomas Aquinas: Philosophy, Theology, and Ethics
St. Thomas Aquinas
Early Life and Education
Born in 1225 in Roccasecca Castle, near Naples, Thomas Aquinas was of noble birth and received his education at the monastery of Monte Cassino. In 1244, he joined the Dominican order and moved to Paris the following year to study under St. Albert the Great. He later taught at the universities of Paris and Naples, passing away on March 7, 1272, at the Abbey of Fossanuova while en route to the Council of Lyons. Aquinas was canonized in 1323 and declared a Doctor of the Church in 1567.
Major Works
Among his numerous influential works are On Being and Essence, Summa Against the Gentiles, and Summa Theologica.
Faith and Reason in the Thirteenth Century
During the tenth century, the works of Aristotle exerted a profound influence on Western thought, largely due to the translations produced by the School of Translators of Toledo. The Muslim philosopher Averroes further translated and commented on Aristotle’s works, and his interpretations gained prominence at the University of Paris. However, certain Aristotelian doctrines clashed with Christian beliefs, such as the denial of creation ex nihilo and the immortality of the soul. To avoid accusations of heresy, some scholars proposed the theory of two truths, suggesting that reason and faith could lead to different, even contradictory, conclusions. While this theory was ultimately flawed, it highlighted the challenge of reconciling reason and faith when they appeared to conflict.
Faith and Reason in St. Thomas Aquinas’s Philosophy
For St. Thomas Aquinas, philosophy and theology represent distinct forms of knowledge. Philosophy employs reason to investigate the natural order, while theology relies on the truths of faith revealed by God, belonging to the supernatural order. Aquinas maintained that reason is not subordinate to faith but rather autonomous and free to draw its own conclusions within its domain, such as natural science and astronomy, without interference from faith.
Truths of Faith
Aquinas believed that certain truths of faith, such as the Holy Trinity, the Incarnation, and the Eucharist, are inaccessible to reason and lie beyond human comprehension. These mysteries cannot be proven or disproven through rational inquiry. However, he acknowledged that other truths of faith, including the existence of God, creation, and the immortality of the soul, can be understood through philosophical reasoning. Despite their accessibility to reason, God chose to reveal these truths to ensure their clarity and universal understanding.
Relationship Between Faith and Reason
St. Thomas asserted that there can be no contradiction between reason and faith, as the truths discovered through reason cannot contradict the revelations of God, who is the source of all truth. If a conflict arises between a truth of faith and a truth of reason, it indicates an error in reasoning, and faith takes precedence, as divine revelation cannot be mistaken. Faith illuminates reason, guiding it towards truths that are otherwise unattainable or clarifying existing knowledge. Conversely, reason can aid in understanding revealed truths, demonstrating that faith is not absurd and resolving any challenges raised against it.
Theory of Knowledge
St. Thomas Aquinas’s theory of knowledge is rooted in Aristotle’s concept of dual understanding, with the following key principles:
- Sensitive Knowledge: According to Aristotle, knowledge of individual objects, acquired through the senses, is the foundation of all human knowledge. It provides the raw materials for developing intellectual knowledge.
- Intellectual Knowledge: This higher form of knowledge is achieved through a mental process called abstraction, which operates as follows:
- When an object is perceived by the senses, an image is formed in the imagination or fantasy. This image represents the individuality of the object, its particular characteristics.
- The intellect then acts upon this image, dematerializing it and extracting its universal form.
- This understanding is then conveyed to the patient intellect, which grasps the universal concept.
- The universal concept, once understood, is modeled after the singular object, which, when illuminated by the intellect, is known in a more perfect and universal way, enabling logical reasoning.
Three Degrees of Human-Specific Knowledge
Aristotle identified three levels of human knowledge:
- Experience: This involves familiarity with a specific type of thing, an immediate and concrete understanding that can be applied to particular instances. It cannot be taught or transmitted but can only be acquired through direct encounter.
- Engineering (Art): This refers to practical know-how, such as the art of healing. It provides a general understanding of things and can be taught or discussed universally, but its application remains specific to individual cases.
- Wisdom: This is the knowledge of first principles and causes, enabling scientific understanding (episteme). These first principles are grasped through intellectual intuition, the work of the intellect or nous.
Metaphysics
St. Thomas Aquinas’s metaphysics shares several elements with Aristotle’s, including concepts like substance, accident, matter, form, act, and potency. However, there are also notable differences.
Types of Beings
Aquinas distinguishes between two types of beings: material or corporeal beings, which are perceptible through the senses, and spiritual or immaterial beings, which are not. For material beings, their essence encompasses not only their form, as Aristotle argued, but also their matter. It is possible to conceive of a being without its matter, except for spiritual beings like angels and demons, which are pure forms.
Essence and Existence
Furthermore, Aquinas differentiates between a being’s essence (what it is) and its existence (the fact that it is) in all beings except God. Essence exists potentially, but existence, or the act of being, is what actualizes the essence. It can be said that existence is to essence as act is to potency. For instance, the essence of a watch is to tell time, but this essence does not produce the actual watch; the existence of the watch is what brings its essence into reality.
Limited Nature of Existence
Existence is limited in nature. Each being exists according to its own essence. The existence of a stone differs from that of a human, for example. In this way, all beings, including immaterial ones, are composed of essence and existence. The only exception is God, whose essence is identical to his existence. God is the only necessary being; all other beings are contingent, meaning their existence is not inherent in their essence. They receive their existence from God, the only necessary being.
The Five Ways to Prove the Existence of God
Structure of the Five Ways
These are the arguments employed by Aquinas to demonstrate the rationality of belief in God, showing that faith is reasonable because God’s existence can be proven through reason. They utilize a posteriori arguments, starting from observed reality to infer its cause, ultimately concluding that this cause is God. The five ways share a similar structure:
- Begin with a natural phenomenon observable through the senses and describe it in metaphysical terms (e.g., the movement of material beings as a transition from potency to act).
- Apply the principle of causality, which states that every phenomenon or reality has a cause. This principle takes different forms depending on the phenomenon under consideration (e.g., the cause of all movement is a mover).
- Reject the possibility of an infinite chain of causes, as this would imply no first cause and therefore no subsequent causes (e.g., a train cannot have an infinite number of cars without a locomotive).
- Conclude that each chain of causes must have a first cause (e.g., an unmoved mover, an uncaused cause). This first cause, upon examination, is identified as the Supreme Being or God.
The Five Ways
- Argument from Motion: There are things in the world that move. But nothing can move itself; everything that moves is moved by something else. This means that for a being to actualize its potential for motion, it requires the intervention of another being already in a state of actuality. To avoid an infinite regress of movers, there must be an unmoved mover, a being that is not moved by anything else but sets other things in motion. This unmoved mover is God.
- Argument from Efficient Causality: In the sensible world, there is an order of efficient causes, where every action that transforms something is itself caused by something else. Nothing can be the efficient cause of itself, as it would have to exist prior to itself. An infinite series of causes is also impossible, as without a first cause, there would be no subsequent causes. Therefore, there must be a first efficient cause, the cause of all other causes. This uncaused cause is God.
- Argument from Contingency: Contingent beings are those that do not have to exist; they could have not existed. We observe that things can exist or not exist, meaning they are contingent. There was a time when nothing existed. But now, many beings exist. For something to begin to exist, it requires the action of an existing cause. Since an infinite series of contingent causes is impossible, there must be a first necessary being, a being that exists necessarily and is not contingent. This necessary being is God.
- Argument from Gradation of Perfection: We find various virtues or positive qualities (goodness, nobility, beauty, truth, etc.) in material things. Some things possess these qualities to a greater degree than others. To have a quality to a greater or lesser extent implies a comparison to a maximum degree of that quality. Therefore, there must be something that is supremely good, noble, beautiful, truthful, etc., a supremely perfect being, from which all other beings derive their qualities by participation. This supremely perfect being is God.
- Argument from Design (Teleological Argument): There are things that lack intelligence or knowledge but still act towards an end or purpose. They do not operate randomly but intentionally, in a way that is suited to their nature. Since they lack knowledge, there must be an intelligent being that directs them towards their end. This intelligent being is God, who guides all things towards their purpose.
Ethics in St. Thomas Aquinas
Eternal Law and Natural Law (Moral)
St. Thomas Aquinas believed in a divine order of the universe, according to which God governs all created things. This is what he called eternal law. The participation of nature in this eternal law is the natural law, which guides each being towards its proper end in the world. These natural laws, or laws of physics, are always fulfilled by all beings. However, they do not govern human behavior in the same way they govern other natural beings. For irrational beings, natural law determines their behavior passively and necessarily; they cannot escape its dictates. In humans, natural law takes the form of the natural moral law, which consists of fundamental precepts that humans must follow to act rightly and achieve their ultimate end, which, according to Aquinas, is the direct contemplation of God. However, because humans are free, they can choose to obey or disobey the natural law; they can do good or evil.
Knowledge of Natural Moral Law
Aquinas believed that we can discern what is good and what is bad because knowledge of the principles of the natural moral law is grounded in the essence of human nature. Therefore, its content is clear, universal (the same for all), immutable (not bound by time or place), and accessible to all human beings.
Basic Precepts of the Natural Moral Law
The precepts of the natural moral law are its fundamental commands. The first precept is to do good and avoid evil. From this first precept, other precepts can be derived rationally, based on the essential tendencies of human nature:
- Self-preservation: Like all substances, humans tend to preserve their own being. This means that any action that harms oneself or others is morally wrong.
- Procreation and Care for Offspring: Similar to other animals, humans have a natural inclination to reproduce and care for their young.
- Pursuit of Truth and Social Life: As rational and social beings, humans are naturally inclined to seek knowledge and live in community.
The Virtues
Aquinas believed that knowledge of the moral law is not sufficient for humans to consistently do good. Moral virtues, which are acquired habits developed through the repetition of good actions, are also necessary.
Positive Law
For Aquinas, the essential tendency of human nature to live in society necessitates the establishment of general rules to organize social life justly. These rules constitute human positive law. Positive law cannot contradict natural law but should be an extension of it. Morality and law both aim at justice, and therefore they are ultimately in harmony.