What happens
Ajax and Thersites trade insults, with Ajax repeatedly beating Thersites while the fool responds with cutting mockery. Achilles and Patroclus arrive, and Thersites continues his barrage, reducing the hierarchy of command to absurdity: Agamemnon commands Achilles, Achilles commands him, he knows Patroclus, and Patroclus is a fool. Achilles finds the proclamation amusing but learns that Ajax will fight Hector tomorrow by lottery, not by direct challenge.
Why it matters
The scene establishes Thersites as the play's truth-teller through calculated dysfunction. His refusal to be silenced by Ajax's fists reveals how violence cannot suppress speech—each blow prompts fiercer insults. When Achilles arrives, Thersites pivots seamlessly from physical antagonist to verbal one, and his reduction of the command structure ('Agamemnon commands Achilles; Achilles is my lord; I am Patroclus' knower; and Patroclus is a fool') operates as devastating social critique wrapped in apparent nonsense. The chain of command, supposedly absolute, collapses into circular absurdity. Achilles laughs, which suggests either his confidence in his own position or his recognition that hierarchy itself is a game.
Thersites' language does what Ulysses' grand speeches about degree accomplish through different means: both expose the fragility of order. But where Ulysses argues theoretically for the necessity of rank, Thersites demonstrates its actual function—a mechanism for fools to command fools, each pretending authority while serving appetite. The scene's humor comes from Ajax's impotence: he can beat Thersites but cannot shut him up, cannot make him respect rank, cannot turn violence into obedience. That Achilles doesn't fight Hector by choice but by lottery strips further dignity from the heroic encounter. The lottery is order without meaning, chance masquerading as necessity.