Lucilius has apparently been demanding an account of Seneca’s days. Seneca says that a person should not do anything that would not be acceptable in public, arguing that it is pointless to conceal things from other people when God sees all. After giving a short summary of his day, which was divided between reading, relaxing, and physical exercise, Seneca changes the subject to drunkenness. Zeno, the founder of the Stoic school, attempted to prove that drunkenness was wrong through a syllogism: No person who is drunk is trusted with a secret, the good man is trusted with secrets, and therefore the good man will not get drunk. Seneca points out that sleep could be proved immoral using this same formula.

Rather than logical proofs, Seneca gives historical examples of those whose drunkenness led to bad results or public mockery. He stresses that this is the right way to prove the dangers of excessive drinking.

Seneca says that he is staying at a house that once belonged to the Roman general Scipio Africanus. Seneca believes Scipio is in heaven not because of the important victories he won but because of his self-restraint and sense of duty.