Philosophical Views on the Soul: Plato, Aristotle, Descartes

Philosophical Views on the Soul

Plato established a dualism between the sensible world and the world of ideas, which results in a dualism between body and soul in anthropology. For Plato, man is a spiritual and eternal soul locked within a body. The authentic and genuine self of man is the soul, destined for wisdom. Body and soul are two heterogeneous realities. The body is of a material nature and belongs to the world of the senses, while the soul is spiritual and belongs to the intelligible world. The soul's natural place is the intelligible world, not close to the body.

For Plato, the soul has three distinct parts:

• The rational soul: Immortal, intelligent, and of divine nature. It is the most noble and high, as its business is to know intellectually and lead the other two parts towards the realization of good and justice, accounting for the virtue of prudence.
• The irascible part: Contains value and will, and is easily led. It accounts for the virtue of fortitude.
• The concupiscible part: Difficult to guide, it represents desire and extravagant sensitive passion. Its virtue is temperance.

Aristotle's Perspective

Aristotle believed that man is a substance, consisting of matter and form. The body works as matter, and the soul as form. Man is a substantial union. The soul, unlike in Plato's view, does not have pre-existence but exists only with the body. The soul is a substance; the only substance is man, composed of body and soul. The soul is to the body what the function is to the organ (e.g., vision to the eye).

The soul, defined as the vital principle, is present in all living things. Man has a rational soul, animals have a sensitive soul, and plants have a vegetative soul.

• Vegetative soul: Present in plants.
• Sensitive soul: Present in animals.
• Rational soul: Present in men.

Each kind of soul is characterized by its specific functions. The human soul, being the highest, has rational functions in addition to the functions of a sensitive soul and those of the vegetative soul.

Descartes' Philosophy

Descartes considered man, the subject of knowledge, understanding, and reason, as the foundation of his entire philosophy. Descartes advocated a dualism in man, who is a composite of two substances: the thinking substance (res cogitans) and the extended substance (res extensa). According to Descartes, these are two different, independent substances, and the soul can exist without the body, meaning the death of the body does not entail the death of the soul.

This position of Descartes, where body and soul are separate substances, has important consequences: firstly, the assertion of the immortality of the soul, and secondly, the affirmation of human freedom. The soul, as a thinking substance, is excluded from the mechanism and the needs of the body.

However, despite conceiving body and soul as two separate substances, Descartes was aware of the real interaction between them in men. The relationship between the soul and body is exerted by the pineal gland in the brain, but Descartes confessed ignorance of its complete mechanism.