The Human Soul: Thomas Aquinas

The Human Soul: Insights from Thomas Aquinas and Aristotle

Aristotle's ideas were reintroduced to Western Europe after the 'dark ages' through Islamic philosophers in the 10th-11th centuries.
His concept of 'hylemorphism' presents the soul not as a separate entity but as intimately bound to the body.
This posed challenges for Christian philosopher-theologians, particularly Thomas Aquinas, as they sought to reconcile Aristotelian philosophy with Church doctrines.

Hylemorphism: A philosophical theory that posits all entities as composed of matter (hyle) and form (morphe).
In Aristotle's view, the soul is described as 'the act of a body.'
Aquinas interprets Aristotle's ideas to argue for a distinction for the intellect, identifying the intellectual soul as 'subsistent'—capable of existing independently and experiencing incorruptibility.

Objection 1: It seems that the soul is a body.
- Argument: The soul is the principle that moves the body; thus, it must also be a body.
- Claim: A mover must itself be moved or be the cause of eternal, unchanging movement (citing Aristotle's Physics).
Aquinas's Response:
- The soul is defined as the first principle of life in living beings (souled); the living body is different from the essentially living (the soul).
- Key Point: Not every principle of life is a soul; examples include the processes of sight managed by an eye.
- Conclusion: The soul, as the act of a body (similar to heat as the act of calefaction), cannot be merely a body despite involving a body in its operation.

Objection 1: The human soul is not subsistent, as it does not refer to a particular thing directly.
Objection 2: Only that which subsists operates; the soul does not perform operations independently.
Objection 3: The soul cannot operate apart from the body.
Aquinas's Response:
- The soul must be both incorporeal and subsistent, serving as the principle of intellectual operation.
- Example used: A sick person's inability to perceive sweetness demonstrates how an impaired organ restricts perception.
- The intellect must be other than a body and takes on knowledge of forms rather than individual instances.

Arguments Against:
- Man shares genus with other animals; one might assume all animal souls are subsistent.
- The operations of sensitive faculties are thought to reflect intellectual operations, thus implying subsistence.
Aquinas's Response:
- Human souls are subsistent due to unique introspective abilities and functions that animals lack.
- Sensitive faculties function alongside body changes, proving they do not operate independently and thus are not subsistent.

Argument: References to the internal man suggest that the soul constitutes the essence of a person.
Aquinas's Response:
- The assertion that the soul is man isn't entirely accurate.
- Man comprises both soul and body; thus, the operations attributed to man are not solely due to the soul.

Aquinas's View: The soul does not contain matter; it is entirely the form of a body.
- A form cannot be a composite of matter since that would introduce potentiality, conflicting with the nature of a form, which is pure act.

Objection: Given man’s earthy origins, one might conclude the human soul is analogous to that of animals and hence corruptible.
Aquinas's Comparison:
- Denies that corruption applies to the soul, explaining that incorruptibility stems from the nature of subsistent forms versus non-subsistent forms (brute souls).
- Conclusion: The human soul is incorruptible because its essence is independently derived from material corruption, in stark contrast to animal souls.

Aquinas effectively navigates between Aristotelian and Christian principles around the nature and function of the soul in humans.
His philosophy highlights a clear distinction between the workings of intellectual operations in humans as subsistent and the sensitivity in animals as not substantiated by the same reason. This aligns with Christian theological views regarding the unique nature of humanity in relation to the divine.