Logic – Overview

In order to understand well just about anything that Saint Thomas Aquinas writes in his philosophy or theology, one should become familiar with the Aristotelian tradition in logic and philosophy, especially as that tradition was handed on to the thinkers of the Middle Ages.

I. Logic and the Seven Liberal Arts

• Boethius and Early Medieval Logic
• The Art of Logic and the Science of Reason

II. Simple Apprehension – The Intellect’s First Act of Abstracting from Sense Experience

• Words, Concepts, Things
• Forming Definitions
• Porphyrian Tree
• The Problem of Universals
• Form or Species
• What the Meaning of “IS” is
• Predicaments – The Ten Categories: Substance and Nine Accidents
• First and Second Intentions

III. Judgment: The Intellect’s Second Act of Composing and Dividing

• Propositions and Judgments
• Truth and Falsity
• First Principles
• Types of Propositions
  • Quality
  • Quantity
  • Square of Opposition

IV. Reasoning – The Intellect’s Third Act of Demonstrating

• Categorical Syllogism
• The Perfect Syllogism – the First Figure
• Hypothetical Syllogism
• Demonstration and Scientia
• Logical Relations Reflect Reality

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Updated January 18, 2025