The Soul: Aristotle and Aquinas

The theory is detailed in Aristotle's work, De Anima.
Aristotle utilizes a familiar distinction between matter and form to explore the essence of the soul.
In the opening of De Anima (II.1), he proposes a framework involving three types of substances:
- Matter (Potentiality): This represents the potential aspect of substance, the underlying substance which has the capacity to develop into something else.
- Form (Actuality): This signifies the actualized state, the defining essence of a substance that provides it with its specific characteristics.
- The Compound of Matter & Form: This combination results in a complete substance, where matter and form operated together.
Classification of living beings based on their souls:
- Animals: Possess a sensitive soul, allowing for motion, sensation, and reproduction.
- Plants: Have a vegetative soul, which supports growth and reproduction.
- Humans: Are characterized by their rational soul, enabling thought, sensation, and reflective capabilities.

Thomas Aquinas advances and integrates Aristotle's theories within a Christian context.
Aquinas posits that the human soul is natural and shares fundamental aspects with Aristotle's views.
Key Aspects of Aquinas's theory:
- Aquinas concurs with Aristotle that the soul serves as the fundamental principle of life; it is what animates and provides essence to a human being.
- He defines the soul as the substantial form of a human being, meaning the soul is what fundamentally makes a human a human.
- The soul is characterized as separable and incorruptible, indicating that it does not disintegrate or cease to exist, emphasizing its eternal and unchanging nature.