Tolstoy first read the philosophical dialogues of Plato, who lived from 427 B.C.E. to 347 B.C.E., in French translation as a young man. He returned to them when he learned to read Greek in the period just before writing Anna Karenina. Plato's dialogues showcase Plato's teacher, Socrates, often even presenting him in an almost beatific light. They usually also show Socrates in action—or rather in dialogue with his pupils. Using what has come to be known as the "Socratic method," Socrates does not come out and tell them the truth, but rather involves his pupils in the process. He asks a series of leading questions, designed to lead to the truth indirectly. Scholars have felt that Tolstoy engages in a similar process in his novels.
The two works that Tolstoy singles out, the Symposium and the Phaedo, are about love and death, respectively. These are two topics at the heart of Anna Karenina. In the Symposium, friends discuss different forms of love at a gathering that features drink and food. The dialogue culminates with Socrates advancing the notion that there is, in addition to physical love, a love of the soul. (He does not necessarily exclude physical love but suggests that under the right circumstances lovers may move from physical love to something higher.) Tolstoy pays direct tribute to the Symposium in Anna Karenina. Chapters 10 and 11 of Part One (pp. 33-43) are a remake of Plato's Symposium featuring Oblonsky and Levin, eating and drinking while discussing love. Oblonsky argues that there's nothing he can do about his sexual appetites and what's wrong with indulging in pleasure anyway? Levin takes a different line, arguing that love can be clear and pure. He even cites the Symposium to back it up (p. 42).
In the Phaedo, Plato meditates on death and the immortality of the soul. In this dialogue, Socrates and his friends gather together one last time in his prison cell. Socrates was tried and condemned to death by the Athenian state. (The parallels between what happened to him and what happened to Jesus were certainly not lost on Tolstoy.) The dialogue reenacts what takes place between him and his friends in his final hours as Socrates takes the poison hemlock that kills him. Socrates faces death with equanimity as he argues for the immortality of the soul. Facing death is a major concern of all of Tolstoy's writings and Anna Karenina is no exception. Part Eight shows Levin struggling to achieve a Socratic acceptance of his own mortality. Tolstoy pays tribute to Plato the philosopher by having a peasant with the same name—Platon is the Russian form of this name—serve as an example to Levin of what it means to love God and live for the soul. (p. 794)