Plato’s Theory of Ideas and Ancient Greek Philosophers
Plato’s Theory of Ideas
In his view of reality, Plato distinguishes between two worlds: that of Ideas, which is the truly real, and the sensible, which is composed of things that the senses show us, which are copies of Ideas. Ideas are therefore the true reality, and their features are like the being of Parmenides: eternal (always existed), unchanged (no change), and intangible (no material component). You could say that they are the models from which the Demiurge constructs the world of sense, that is, imitating Ideas.
These two worlds are composed of entities with different characteristics: while Ideas are unique, eternal, immutable, and intangible, things are sensitive, multi-perishable, changeable, and material. Given these characteristics, we can explain the infinite variety of people that exist in reality. There are sensible people, and we know them as such because they are copies, imitations of the Idea of a person, a human being, which is unique and unchanging. The Idea gives things their being, essence, and the possibility of knowing them.
Moreover, in the world of Ideas, there is a hierarchy: at its lowest level, consisting of mathematical Ideas, passing through Ideas of beauty and justice, this order culminates in the Idea of Good. Plato’s Idea of Good is compared to the sun in the world, which gives life to material things. Therefore, it is the ultimate principle of reality and the basis of knowledge.
Knowledge
Plato is against the Sophists because they defend a knowledge of appearances. So when we want to know what things are, we need to apply a method that leads us through slight dialectic (which is the promotion path that leads man from knowledge of the sensible world to real-world knowledge of Ideas), the knowledge of Ideas.
Thales
Only after making mistakes and correcting them can we make progress. The ideas are in themselves, regardless of the personality, character, race, or faith of their proponents. He was able to predict the solar eclipse.
Formal sciences use concepts or conceptual constructs as referents. Their goal of study is arguments and theories, and their research methods are analytical-deductive demonstration (analyzed from the universal to the particular).
Empirical science concerns observable events, starts from events, and tries to explain them, to establish theories and generate predictions. Its subject is the material world, nature, the historical world, social and cultural development; its method is comprehension and experimentation.
The Myth of the Cave
The Myth of the Cave is the most famous of Plato’s myths, which explains his theory of Ideas, his epistemological theory, and his anthropological theory. It places us in a cave where there are prisoners who all their lives have been forced to look at some shadows caused by a fire and some moving objects. In this first metaphor, the author identifies the prisoners chained to the human soul, which is tied to an earthly body and belongs to the world of things, and is therefore imperfect and sensitive, whose skills are mere shadows of reality.
In the myth, Plato wondered what would happen if one of the prisoners were to stand and be able to see the fire and the real objects, saying he would feel pain and would realize that what he saw before were only shadows of reality. And if you rise to the surface, something similar would happen. This release is one that allows human beings to rid the world of sense and achieve the ideal world, which is perfect, eternal, and unchanging, and which can be accessed only through the soul and reason.
In the aspect of knowledge, the myth identifies the cave as the world of things. In it, there are imitations of the water (the world of Ideas), but they are imperfect and misleading: the shadows on the wall are imitations of the shadows of objects on the surface, fire is the imitation of the sun. Against this background, prisoners can only know what they see, that is, they can only see shadows on the wall, and they identify them with reality. So when one is released and is capable of seeing the fire and other elements of the cave, he would be closer to true knowledge. However, this knowledge would not be complete but would be what Plato called Doxa, or opinion. If the prisoner is forced to ascend to the surface, there he may observe and watch the outside world, the world of Ideas, he would gradually see the objects that compose it: first the shadows, later objects reflected in water, then objects themselves, the night sky, and finally, the sun, which is identified with the supreme Idea of Good. The knowledge gained here would be true knowledge, that which Plato calls Episteme.
Anaxagoras
- The sun is made up of land and is an incandescent metal sphere.
- He explained eclipses and the phases of the moon.
Aristotle
- The Earth is the center of a sphere, where the stars are fixed.
- “The Earth is fixed and immobile.”
- The sun and moon and five planets visible from Earth describe a circular motion in their own areas.
- Each sphere is inside another, and all within the celestial sphere.
Xenophanes
Rejection of traditional knowledge.
Philosophers: Thales, Anaximander, Anaximenes
They come from Miletus, are Milesians. The three proposed a monistic explanation: the arche of the universe comes from a primordial substance from which everything arises, Thales and Anaximenes proposed water and air respectively. Anaximander proposed that the principle is a substance called apeiron (indeterminate, infinity). Heraclitus proposed fire as a primary element, being in constant transformation because it obeys a law or measure. The Pythagoreans founded the school of Pythagoras.
The Sophists are the group of thinkers who flourished in the second half of the 5th century BC, which has two main features: their teaching included humanistic disciplines (rhetoric, politics, law, morality, etc.) and they were the first teaching professionals with an education project well defined. They paid special attention to the institutions and rules that govern life, these were called “nomos” (law, custom) contrasting “nomos” to “physis”, the rules are the result of a convention of nature. They defended cultural relativism; there is no absolute truth, but truth is relative to who knows it.
Parmenides
He wrote a religious poem. He makes a number of invocations to win the favor of an unidentified goddess in order to gain access to true knowledge. Parmenides presents his doctrine: the claim of being and rejection of change. Being is one, and the affirmation of multiplicity that implies becoming, and becoming himself, are nothing more than wishful thinking. There are two ways to access knowledge: the way of truth and the path of opinion.
Zeno
- Greek Philosopher
- Uses logic to prove that being is one and not multiple
- Movement exists only in the illusory world of the senses
- Stoic philosophy (Zeno the Stoic)
- Life led by reason (free from passion, dignity, and self-respect)
- Taught philosophy in Athens concentrating on the system of metaphysics
- The Eleatic paradox shows that an object in motion is actually at rest
Anaximenes
- Air: parent, to which all other things can be reduced
- Movement separates but does not give rise to elements
- Tried to discover the ultimate nature of reality
- Cosmos = holding a sun and moon lest they fall to Earth
- Improved and enhanced sundials
- Thought that the Earth was flat and there is nothing under it
- Arche (apeiron): what is before air
- Transformed by rarefaction and condensation