Plato’s Philosophy: Ideas, Knowledge, and Reality

Posted on Feb 12, 2025 in Philosophy and ethics

Plato created a new philosophy that advocates for anthropological dualism (between soul and body). It also addresses important issues of epistemology, ontology, ethics, and politics. He was influenced by other philosophers of the time:

  • Socrates: This influence can be divided into two points:
    • The first is to obtain a definition of virtues and behaviors, for which Plato would create a neologism: the idea.
    • The second aspect received from Socrates was the importance of morality, known as Socratic intellectualism.
  • The Pythagoreans: They transferred to him their interest in mathematics.
  • Heraclitus: His conception of movement (all is in constant change) prompted Plato to create the theory of ideas.
  • Parmenides: Plato’s influence can be seen in the importance of reason as a means of understanding reality and the Platonic division of the world into two realms: the sensible and the intelligible.
  • Zeno of Elea: A pupil of Parmenides, he transmitted the importance of the dialectic of rational discussion as the best instrument for refining concepts and obtaining a more complete conclusion.

Plato’s Theory of Ideas and Ontology

Plato’s theory of reality (ontology), or theory of ideas, conceives of ideas as the true self—that is, absolute truths, eternal, immutable, and independent of the phenomenal world. Plato believes that there are two worlds:

  • The Intelligible World: It is composed of intelligible ideas, archetypes of the material things of the sensitive nature, which are the true reality but are invisible and can only be seen through intelligence. These are also hierarchical: the first is the idea of good that illuminates all the others and gives intelligibility to noetic objects, then the abstract ideas (justice, beauty, etc.), followed by numbers, and finally the ideas of sensible objects.
  • The Sensible World: It is subject to generation, is only a copy of the intelligible, and is perceived by the senses.

Plato’s Epistemology

Plato’s epistemology (philosophy of knowledge) is well represented in the Myth of the Line or the Myth of the Cave, which distinguishes four degrees of knowledge:

  • Eikasia (Imagination): The knowledge of the sensible world’s images (shadows in the cave).
  • Pistis (Belief): Knowledge of the sensible world’s objects. These kinds of knowledge are sensible and provide opinion or doxa (knowledge of things of the visible world is changing).
  • Dianoia (Discursive Thought): Knowledge of mathematical entities.
  • Dianosis (Science/Dialectic): Knowledge of ideas, dialectic. These two provide intellectual knowledge and knowing, or episteme.

The Myth of the Cave

The Myth of the Cave is a metaphor for how mankind, and therefore us, are faced with a situation of deception. The story says that we are chained hand and foot, with our necks facing shadows (images of the sensible world) projected by the fire (the Sun) and emitted by some figures (objects of the sensible world) carried by men who walk. Since we were kids, all these slaves think they are seeing reality, as they have not seen anything else in their lives, but they are only seeing shadows.

Then someone (a philosopher) frees them from their delusion, disrupting their schemes, greatly bothering them, and causing them great pain for change. It is here, and only here, when the slave sees the figures casting shadows, that he could see and realize that those shadows were not reality. Now, thinking that the figures are, recognizing that reality and has been deceived all this time. When he exits the cave and sees the light of the sun, it takes some getting used to, but gradually he begins to see shadows and reflections, and then the figures that project them. He then realizes that the figures of the cave were not real but representations of reality. He is now in a state of disappointment and discovery, with a thirst for knowledge running inside him.

But not satisfied, the slave will now want to go to disabuse the other slaves who are chained in the cave. They will not believe what he says, nor will they be pleased to try to free them because they are necessarily very comfortable in that situation and do not want change. They even try to kill him.