The "sound argument" of the title refers to the cold logic that sacrificing one individual (Historia) is a necessary evil to save the nation.
: The episode highlights the growing instability of Eren, who has grown cold and detached, alarming his closest friends, Mikasa and Armin. 10 : A Sound Argument
: A small-scale display of the Wall Titans' power to deter world invasion. The "sound argument" of the title refers to
If you are referring to the episode " A Sound Argument " (Season 4, Episode 10), it is a story centered on the heavy burden of duty and the erosion of hope. who has grown cold and detached