Plato’s dialogues are classified into early, middle, and late periods—with the works in each period having distinct characteristics that set them apart from the works in the other periods.

Early Plato, Elenchus, and The Apology

The early dialogues, including The Apology, written soon after Socrates’s death, provide the nearest portrayal of what Socrates’s philosophy might have been. In these dialogues, Plato focuses almost exclusively on ethical questions, using the Socratic method of elenchus. In a typical early dialogue, Socrates asks his interlocutor for a definition of some virtue (piety, courage, etc.); once the definition is offered, he shows that the definition is inconsistent with other beliefs that the interlocutor holds. The interlocutor refines his definition, and Socrates shows that the new version is still inconsistent with other beliefs. This cycle of revisions and rebuttals is intended to continue until a satisfactory definition is reached, but this never actually happens in any of the dialogues. With the exception of a few key doctrines, no idea ever emerges from elenchus still looking tenable. A typical early dialogue ends in a state of aporia—intellectual gridlock, where all existing beliefs on the topic have been rebutted, but progress seems impossible. The interlocutors know what they thought before was wrong, but they are not told what to believe instead.

These dialogues should not be considered failures. According to Socrates, the goal of elenchus is not to reach definitions. He claimed that engaging in philosophic dialectic is crucial to human well-being—rendering people both happier and more virtuous. He believed this so strongly that, by some accounts, he chose to be executed rather than give up the practice. Though in the early dialogues Plato utilizes Socratic methods, he does not accept everything taught to him by Socrates. He explores many of these views critically, laying them out but not necessarily endorsing them.

In The Apology there is only one appearance of another speaker other than Socrates, Meletus (24b – 28a), and it is the only instance of the elenchus. Importantly, however, The Apology marks an interesting point in Plato’s works because it represents an instance in which Socrates refers to Plato as his student by name. While most of the dialogues in Plato’s other works are usually told by a third or fourth party who heard from a friend or acquaintance about a dialogue of Socrates’ at which another friend was present, The Apology presents Socrates’ words verbatim, without any framing devices to distance the narration. Plato in this case makes a particular effort to point out that he was actually present at Socrates’ defense. The purpose here might be to lend the retelling a certain authenticity: the author was present at the trial, and has copied down Socrates’ speech word for word. It would be important for Plato to be able to claim such authority, as he wishes to acquit Socrates posthumously as much as possible. 

Middle Plato, Socrates, and the Theory of Forms

In the middle period, Plato develops a distinct voice and philosophical outlook. The figure of Socrates becomes more of a mouthpiece for Plato’s own views. He relies less on the method of elenchus and presents his dialogues as conversation between a teacher and his students rather than as debate between a philosopher and his opponents. Instead of aporia, interlocutors arrive at positive conclusions. Ideas hinted at in the early dialogues, such as the theory of Forms, emerge as full-fledged doctrines. Plato’s interests broaden beyond ethics into epistemology and metaphysics. He draws on his theory of Forms and the idea of the soul to explore old questions about how to live, the nature and role of love, and the nature of the physical world.

The Republic is paradigmatic of the shift from the early to middle periods. Book I adhers to the structure of a typical early dialogue. Some speculate that it originally stood on its own as a dialogue dating from the early period (in which case it would have been called Thrasymachus). Plato has Socrates use the method of elenchus in an attempt to pry out a definition of justice, and the result is aporia. Instead of leaving off there, Socrates picks up the question in Book II. He hashes out a detailed positive theory of justice over the course of nine more books. In these books, rather than employing the elenchus, Socrates mostly lectures, pausing intermittently to respond to objections raised by his students, Plato’s two brothers. In Book VII, Socrates warns against elenchus. He declares that philosophical dialectic is dangerous in the wrong hands and should only be taught to the right people and only then when they are old enough to use it properly. He warns that those without the proper respect for truth would use the method in order to argue against everything instead of using it to seek out what is right. This discussion might explain what motivated Plato’s shift in methods of inquiry and what motivated him to found the Academy.

Late Plato and Socrates’ Views on Death

The later dialogues are extremely difficult and controversial. They contain Plato’s most complex philosophical and logical views, and there is little agreement over what trends and themes define this period. One work among this later group is worth mentioning in relation to The Apology, Plato’s Phaedo, a more mature work that deals primarily with questions of the immortality of the soul. An early work, The Apology centers more around Socrates’ philosophical opinions, which, as he so persistently claims, are agnostic regarding any factual questions. In the later Phaedo, however, we see Socrates claiming to have positive knowledge of what happens after death. As for The Apology, Socrates concludes in typical manner, acknowledging that he does not, and cannot, know for certain what awaits him after death.