Plato, The Republic: On Justice – Dialectics and Education

 In The Republic of Plato, the highest form is considered to be the Form of Good, the source of all other Forms that could be known by reason. The central theme of the book is justice, argued with the help of several Platonic theories, including the allegorical myth of the cave, the doctrine of ideas, dialectics, the theory of the soul, and the design of an ideal city.

 His dialectic is a type of knowledge, with an ontological and metaphysical role, which is reached by confronting several positions to overcome opinion (doxa), a shift from the world of appearances (or "sensible") to intellectual knowledge (or " intelligible ”) to the first principles.

 Plato's educational model (paidèia) differentiates the level of education according to the students' skills. According to Socratic principles, in order to do justice, one must know what is good, and this is best known to the philosopher. Plato detailed this concept, highlighting the distinction between the philosopher (who seeks the principles of truth without claiming to possess it) and the sophist (who lets himself be guided by opinion as the only valid parameter of knowledge).