Plato’s Key Concepts: Intelligence, Justice, and the Worlds
Plato’s Key Philosophical Concepts
Intelligence (Nous, Noesis): Human power that captures the essences that are the real, immutable reality. Faced with appearance, which is the view, intelligence reaches the truth. Science and discursive thought are the two degrees of expertise of intelligence. Intelligence (nous) is, for Plato, the immortal human soul: the rational soul.
Justice in Plato’s Philosophy
Justice: Virtue consists in the hierarchical, orderly, and harmonious arrangement of the three parts of the soul in man and the three types of citizens in the polis. Justice is the virtue of a structured harmony, reached when each part properly belongs. Thus, we can speak of a human being as just when the rational soul is wise, the irascible soul is strong, and the concupiscible soul is moderate. Similarly, a state is just when rulers, warriors, and producers are respectively wise, courageous, and moderate.
The Intelligible World
Intelligible World, Essence, Being, Idea: Reality subsistent, independent of sensible things, intangible, immutable, and eternal, which is captured with intelligence. Eidos is usually translated as form or idea and designates the true reality, being (to on), the essence (ousia), compared to sensible things, which are mere appearances of ideas that serve as a model. The ideas are the subject of science and have the following characteristics: they are unique (compared to the multiplicity of the sensible), perfect, immutable, and only intelligible. The ideas or essence as a whole constitute the intelligible world. These realities, which are authentic selves, have an important character in that they are independent of both the subject who thinks of them (because they are not mere mental contents) and the objects that are its essence (the sensible things that mimic them).
The Sensible World
Sensible World, Generation: Reality multiple, changing, and imperfect, as it is the object of perception. Sensible things are or mimic the ideas, which are the models to which the sensible must conform. This plurality changes forms and creates a seemingly sensible world, whose knowledge is limited and whose opinion cannot be transcended without the intervention of intelligence. Its degree is, therefore, lower than the intelligible world, which serves as a model and is the genuine reality.
Opinion and Knowledge
Opinion: Knowledge sensitive aims at constant becoming in its own physical world. Faced with the reality of the real and eternal intelligible essences, captured by intelligence, opinion does not reach the imperfect knowledge of the apparent reality and changing world of sense. Belief and imagination are the two degrees of knowledge characteristic of opinion.
Discursive Thought Explained
Discursive Thought: Levels of knowledge, an introductory science itself, which is higher than opinion (in that it aims to intelligible realities) but lower than science (in terms of assumptions that cannot be justified). Discursive thought can progress from severe premises. It uses scenarios, leaving these intact for not being able to account for them.
Prudence is based on knowledge of the truth and the idea of good under the rational soul itself. Wisdom consists in properly governing both their lives and the city. As the pilot in a ship or the winged charioteer must know where to go and the best way to reach their destination, prudence is the virtue of knowing in each case the most convenient point to the good of one’s own life and the direction of the city.