Thomistic Philosophy: Key Principles and Concepts
Knowledge and Faith
Reason and faith can lead to conflicting conclusions. Common truths serve as preambles to faith, accessible through both reason and revelation. Understanding is preferable to blind belief. Certain truths, revealed by God, are necessary for salvation or beyond human comprehension. Theology demonstrates that faith is not anti-rational, but supra-rational.
Knowledge Acquisition
According to Aquinas, every being has a way of knowing. Angels, saints, and saved souls possess direct knowledge of God. Humans, as composite beings of body and soul, rely on senses and abstraction (de-individualization and dematerialization) to acquire knowledge.
Ontology
We can conceive of non-existent beings (e.g., a perfect state) and understand their essence. Only in God do essence and existence coincide. God is being, existing in itself. Creatures have being because God grants it. God’s existence is inherent in its essence, unlike creatures.
Creation, Participation, and Analogy
God created the world through a free act of will, without diminishing its fullness. Creatures participate in being. Imperfect creatures partake in perfection without possessing it fully. This raises the question of the relationship between God’s being and that of creatures. Aquinas rejects two solutions:
- Platonism: Only God possesses true being; creatures are mere appearances.
- Pantheism: If God is the only true being, then everything is God, eliminating the distinction between God and creatures.
Aquinas proposes the analogy of being: God’s being and that of creatures are similar in some ways and different in others.
Anthropology
Aquinas adopts Aristotle’s theory but grants the soul the capacity for salvation. The human soul is immortal. Humans are a composite of body and soul, forming a single reality in substantial union. Soul and body maintain a degree of independence. The soul, being immortal, can exist independently after death. The soul has three functions: vegetative, sensitive, and intellectual. The object of human knowledge is truth, which is ultimately one with God.
Ethics
Aquinas’s ethics draws from Aristotle, the Church Fathers, and St. Augustine. God is the cause, origin, lawgiver, and judge of all. Moral acts are judged by their conformity to God’s will. While Aristotle equates morality’s end with happiness, Aquinas defines true happiness as beatitude: the vision, contemplation, and enjoyment of God in the afterlife. Morality is the rational creature’s movement towards God. Achieving this requires grace, which complements, not negates, human nature. Aquinas distinguishes between eternal law (God’s plan for governing), natural law (creatures’ participation in eternal law), revealed divine law, and human positive law. State law should be an extension of natural law.
Politics
Humans are social beings, needing society for survival and fulfillment. Society is natural, not artificial. The state, the natural form of society, is necessary for social organization and governance. The state’s purpose is the common good, peace, and prosperity. Since these ends are subordinate to the Church’s aim (salvation), the State is subordinate to the Church. Monarchy, mirroring God’s rule and the mind’s rule over the body, is the best form of government. Tyranny is the worst, as it represents the greatest abuse of power.
Philosophy of Nature
Aquinas’s philosophy of nature is Aristotelian.
Philosophy of Religion: Five Ways
Aquinas offers five ways to demonstrate God’s existence:
- Motion: Everything that moves is moved by something else. There must be a first mover, unmoved itself, which initiates all motion. This unmoved mover is God.
- Efficient Causality: Everything exists because of a cause. There must be an uncaused first cause, which is God.
- Contingent Beings: Creatures are not necessary. There must be an absolutely necessary being, existing by itself, which is God.
- Degrees of Perfection: Varying degrees of perfection imply an absolute perfection, a standard for comparison. This perfect being is God.
- Teleology: Non-intelligent beings exhibit ordered behavior, suggesting an intelligent organizer. This supreme intelligence is God.