Plato and Aristotle: Metaphysics and Epistemology

Plato's Theory of Ideas and Metaphysics

In his Theory of Ideas, Plato addresses the metaphysical question by stating that the truth is permanent, consisting of ideas or prototypes of reality.

Characteristics of Ideas

The characteristics of ideas are that they are unique, perfect, eternal, and unchanging.

The Duality of Reality

Plato describes a duality of reality consisting of:

• The World of Ideas: True and perfect, representing our heritage.
• The World of Things: The sensible world, which is temporary, limited, and imperfect.

The intellect perceives immutable ideas that are real, immaterial, intelligible, inimitable, eternal, infinite, and spiritual (supersensible and superempirical). In contrast, things belong to "the becoming" and are mutable, false, sensitive, material, limited, temporal, and empirical.

Epistemology and the Soul

Regarding the epistemological question of whether knowledge originates in the senses or the intellect, Plato accepts innate knowledge. He believed in the immortality of the soul and, consequently, in innate intelligence.

For Plato, the theory of knowledge is reminiscence (anamnesis or recordar). According to Plato, our soul knows all ideas and knowledge; however, when it leaves the body and moves to another, it forgets what it knew before. Nevertheless, what our senses perceive as real objects serves as a spur for us to remember. Thus, to know is to remember what the soul had already lived or known in the World of Ideas.

Aristotle: The Stagirite and the Lyceum

Aristotle (383–322 BC), a Stagirite-Macedonian, wrote a book on metaphysics, causes, and the principles of scientific reality. As a philosopher, he was perhaps the most complete, conducting extensive research. He taught Alexander the Great (who was wise in medicine), and both benefited from the relationship. Having lived as a child in a scientific environment (his father was a senior physician), Aristotle saw his culture expanded by Alexander. Alexander provided him with significant funds for research and assigned slaves to act as collectors, allowing Aristotle to classify the realms of nature. His method was to leave no issue without study. When Alexander died, Aristotle went to Chalcis. Aristotle did not miss Athens and founded his own school, the Lyceum. Aristotle of Stagira was known as a great reader and a professor of the best rhetoric. The Lyceum was the school of the wandering Peripatetics, named for those who walked through the gardens.

Aristotle died a year after Alexander in Chalcis, leaving behind a critical theory of ideas.

Aristotle's Epistemological Theories

Aristotle denies innate ideas. He posits that knowledge is progressive: sensitive knowledge leads to intellectual knowledge. The senses capture a sensible base, which then becomes a concrete and private image. Through a process of abstraction and generalization, the intellect transforms this into an idea, which is abstract and universal.

His approach is empirical; in this way, Aristotle brings sensationalism (a primitive form of empiricism) into dialogue with rationalism.

Scientific Observations

In science, he studied concepts such as inertia, carts, and refraction. He believed the subject receives information from the disordered senses, and the individual then commands and gives it meaning.

Metaphysical Theory

His metaphysical theory was influenced by:

• Parmenides: The concept that being and non-being is not a static or permanent reality, yet remains immutable.
• Heraclitus: The concept of Becoming, where reality is always changing.