Aquinas's Synthesis of Faith and Reason

Jul 31, 2025

Overview

This lecture introduces Thomas Aquinas’s synthesis of faith and reason, his distinctions between types of knowledge, and his five arguments for God’s existence.

Thomas Aquinas: Background and Significance

  • Thomas Aquinas was a 13th-century Italian monk and philosopher.
  • Major works: Summa Contra Gentiles (philosophy) and Summa Theologiae (systematic theology).
  • Aquinas synthesized Christian theology with Aristotle’s philosophy, unlike previous thinkers who favored Plato.
  • His views are central to the question of what it means to be human.

Faith and Reason: Aquinas’s Approach

  • Aquinas argued that faith and reason are not in conflict but are complementary.
  • Early civilizations did not see a problem integrating reason and religious belief.
  • Faith is often seen today as contrary to reason, but Aquinas challenges this.
  • All knowledge requires some foundational beliefs or assumptions.

Two Categories of Knowledge About God

  • Some knowledge (e.g., the Trinity) requires divine revelation and cannot be attained by reason alone.
  • Other knowledge (e.g., God’s existence) can be discovered through human reason.
  • Both types of knowledge are valid and form a taxonomy of how we know things.

Limits of Human Reason

  • Human reason alone could only lead a few people to knowledge about God.
  • Gaining such knowledge through reason would take a long time and require maturity.
  • Human reason is prone to error and cannot fully grasp God’s substance.

The Role of Divine Revelation

  • Divine revelation is necessary for truths that exceed human reason.
  • Theology (the science of God) uses philosophy to clarify its teachings.
  • All reasoning begins with basic assumptions (articles of faith) that are not themselves proven.

Self-Evidence and Proof of God’s Existence

  • Some truths are self-evident in themselves; others can be made evident through argument.
  • Aquinas critiques Anselm’s ontological argument for lacking persuasiveness.
  • Aquinas prefers a posteriori (from experience) arguments based on observable effects.

Aquinas’s Five Ways (Arguments for God’s Existence)

  • Argument from Motion: Everything in motion is moved by something else; there must be a first mover (God).
  • Argument from Causation: Nothing can cause itself; there must be a first cause (God).
  • Argument from Contingency: Not everything can be contingent; there must be a necessary being (God).
  • Argument from Gradation: Degrees of goodness, truth, etc., imply a maximum; this ultimate standard is God.
  • Argument from Design: Natural things act towards ends; this purposeful order suggests an intelligent designer (God).

Key Terms & Definitions

  • Faith — Belief in truths revealed by God, not attainable by reason alone.
  • Reason — Human capacity to think logically and derive knowledge from experience.
  • Divine revelation — Knowledge given by God through scripture or supernatural means.
  • A posteriori — Knowledge or arguments derived from experience or observable effects.
  • Contingency — The quality of depending on something else for existence.
  • Necessary being — A being whose existence is not dependent on anything else; must exist.

Action Items / Next Steps

  • Review Aquinas’s Five Ways in the assigned readings.
  • Consider how Aquinas distinguishes between knowledge gained by faith and by reason.
  • Prepare for discussion on the implications of Aquinas’s arguments for the understanding of humanity.