Comparison of Plato and Aristotle’s Philosophies
Anthropology
Plato advocates a radical dualism: man is composed of two entirely different entities, soul and body. The union between them is merely accidental and unnatural. The body is a prison for the soul, an obstacle to knowledge. The soul would be better off without it. This negative conception of the body was adopted by Christianity and defended by figures like St. Teresa of Jesus and San Juan de la Cruz, who expressed a desire to leave the body to unite with God, viewing life as a difficult stay in an unpleasant inn.
In contrast, Aristotle argues for a substantial union between body and soul. If one is missing, there is no human being. The body is the matter, and the soul is the form. If the body dies, the soul ceases to exist. Aristotle denies the immortality of the individual soul, a concept Plato defended.
Regarding the soul’s meaning in Greek philosophy (as a principle of life and knowledge), Plato primarily viewed it as a principle of knowledge, while Aristotle considered it primarily as a principle of life. Aristotle distinguishes three types of souls: vegetative, sensitive, and intellective. Humans possess an intellectual soul that encompasses the functions of the sensitive soul of an animal (sensation, movement) and the vegetative soul of a plant (nutrition, growth).
Ethics
Aristotle opposes the intellectualism of Socrates and Plato. According to Aristotle, being good is not solely about knowing what is good, but about developing habits based on actions deemed appropriate by reason. Virtue depends not only on knowledge but also on the love and repetition of virtuous acts, forming habits.
Aristotle also opposes Plato’s idea of an absolute and unique good. He believes each being has its own good. For humans, it is self-realization through reason. This self-realization cannot be universally defined; each individual, based on their nature and circumstances, must choose what suits them best, acting with prudence and wisdom, seeking the middle ground between extremes.
Politics
Plato’s ideal form of government is aristocracy, or the rule of the best, who are the wisest philosophers. However, aristocracy can degenerate into timocracy, then oligarchy, democracy, and finally tyranny. Plato’s political philosophy aims to establish mechanisms (education of rulers, communism of property) to prevent this degeneration.
Aristotle believes there isn’t one valid form of government. The key is that the government pursues the common good, which can be achieved through monarchy, aristocracy, or politeya (republic or constitutional government). He rejects their degenerate forms: tyranny, oligarchy, and democracy, where the focus shifts from the common good to the benefit of one, a few, or the many, respectively.
Knowledge in Aristotle
Unlike Plato, who believed knowledge is recollection, Aristotle argues that there is nothing in the understanding that wasn’t first perceived through the senses. There are different levels of knowledge:
- Sensation: The lowest level, common to all animals. Some animals also have memory and imagination.
- Experience: Rational coordination of sensations, a precursor to science and art.
- Imagination: Allows mental reproduction of objects, enabling understanding and science.
- Understanding: The highest level of knowledge, enabling thought and judgment.
Aristotle distinguishes two principles in intellectual operation: active intellect (agent) and passive intellect (patient). The active intellect is immortal and eternal, abstracting forms from images received by the passive intellect, which are then formed into universal concepts of science. The active intellect is immortal and eternal, while the passive intellect is corruptible and mortal.
Aristotle divides the soul into rational and irrational parts. His later work contradicts his earlier theories, suggesting the soul is of the same nature as the body and is created when it enters the body.