Plato's Republic explores the nature of justice. Socrates, through dialogues with various interlocutors, investigates different definitions of justice, ultimately arguing that a just life is superior to an unjust one, both in terms of individual well-being and societal harmony. The discussion extends to ideal forms of government, education, and the soul's composition, utilizing metaphors like the allegory of the cave to illustrate philosophical concepts. Key themes include the importance of reason, the pursuit of knowledge, and the ideal state's structure, with significant attention paid to the role of philosophy and the limitations of art and poetry. The text also examines the cyclical nature of political systems and the corresponding characteristics of individuals within those systems.

Plato's Meno primarily explores the question of whether virtue can be taught. Socrates and Meno engage in a discussion that examines various definitions of virtue, ultimately concluding that it is neither innate nor learned but rather a divinely bestowed gift. The text also introduces Plato's theory of reminiscence, suggesting that learning is a process of recollecting pre-existing knowledge from a past life. Finally, a substantial section analyzes Plato's theory of Forms, comparing it to the philosophical approaches of later thinkers.

Plato's Apology is a transcription of Socrates' defense speech at his trial in Athens. Socrates recounts accusations leveled against him, including impiety and corrupting the youth. He defends himself by explaining his philosophical method of questioning those believed wise, revealing their lack of true knowledge. Ultimately, Socrates accepts his death sentence with calm dignity, asserting his commitment to philosophical inquiry and belief in divine guidance. The text explores themes of truth, justice, and the examined life.