Aristotle, Aquinas, and the Soul: A Philosophical Examination
1. Aristotelianism. With the collapse of the Western Roman Empire, Greek philosophy and science—also prohibited in the Eastern Roman Empire—were lost. Teachers migrated to Syria and then the Islamic world, carrying important works to open schools and pass on this knowledge. Thus, Greek culture met the great Muslim civilization, which became the heir to Greek science and philosophy. Works were translated from Greek into Syriac, from Syriac into Persian, and from Persian into Arabic. In the Western Roman Empire, only copyists remained, copying works aligned with Christianity. Aristotle was largely lost, except for his logic, preserved primarily by Boethius. However, those who emigrated preserved knowledge of Aristotle, and Muslims also acquired this knowledge. Muslim culture flourished in Spain, particularly in Cordoba, during the Golden Age of Islam (12th century). Two important figures in Cordoba were Maimonides (a Jewish philosopher who incorporated Aristotelian ideas into Jewish tradition) and Averroes (a leading expert on Aristotle’s works in the Islamic world). Another important figure was Ibn Arabi in Murcia (a leading figure in Sufism, the mystical stream within Islam). By the 13th century, Islam was far ahead of Christianity, prompting Christian theologians to rediscover Aristotle, largely through Averroes.
This rediscovery took two paths: using copies translated from Greek into Syriac, Persian, and Arabic, then translating from Arabic into Latin (an unreliable source), or seeking direct translations from Greek into Latin. This rediscovery of Aristotle revealed several dogmas incompatible with Christian dogma:
- The Conception of God: For Aristotle, God was a being knowable only to itself, with no knowledge of or power over the world. For Christians, God was omnipresent and omnipotent, requiring a correction of Aristotle’s concept of God.
- The Conception of Matter and the Cosmos: Aristotle believed matter was eternal, while Christians believed God created the world, making eternal matter incompatible with Christian belief.
- The Mortality of the Soul: Aristotle believed the human soul was mortal and not created by God, with only creative intelligence being immortal. Christianity, however, believes in the immortality of the soul and life after death, requiring an individual soul created by God.
- The Double Truth: Averroes integrated Aristotelian ideas into Islam, proposing the doctrine of double truth: an idea can be expressed religiously or philosophically (religion using myth, philosophy using abstract language). Averroes considered the philosophical interpretation superior. This concept, known as Latin Averroism (with Siger of Brabant as a key figure), was condemned by the Church.
Despite these problems, Thomas Aquinas created a Christian theology based on Aristotelian philosophy (replacing Plato, which had been the basis of Christian theology until the 13th century).
2. Anthropology
Thomas Aquinas, like Aristotle, believed man is a material substance (body) and form (mind), but disagreed on the mortality of the soul and the universality of the intellect.
2.1. Immortality of the Soul
Aristotle believed the soul depended on the body, and vice versa; thus, with death, all but creative intellect perished. Aquinas, however, maintained the Christian dogma of life after death and the survival of the soul. He amended Aristotelian anthropology, stating the human soul was created by God and could only be destroyed by God’s will—a contradiction, as what is born must die. Aquinas argued the soul-body relationship was one of knowledge and temporary; the soul continues to exist after the body dies. He based his defense of the immortality of the soul on three ideas:
- A material soul would be limited to objects of the same composition. Since the soul can perceive beyond material objects, it is not material and not limited.
- A mortal soul could not know itself, but the soul does know itself.
- The desire for immortality: all living beings seek to avoid death. This natural tendency, Aquinas argued, was set by God, implying a real desire shared by humans and animals. The difference, he said, is that animals are not aware of their existence or death in the abstract, while humans are. Animals rely on instinct to survive, but if animals had immortal souls, there would need to be a paradise for them.
2.2. Individuality of the Soul
Aristotle distinguished between passive intellect (forming concepts, judgments, and reasoning) and creative intellect (observing and unaffected), which seemed individual. Averroes argued for a universal passive intellect, contradicting the Christian idea of individual reward or punishment after death. Aquinas modified Averroes’ arguments:
- Creative Intellect: If this intellect were universal and always the same, its actions would be independent of the individual. Aquinas argued it is individual and not unique.
- Passive Intellect: If the intellect were universal and unique, individuals could only think concepts previously thought, and all would be equally intelligent, eliminating individual differences. Therefore, the intellect must be individual.