KING: How well he's read, to reason against reading!
DUMAINE: Proceeded well, to stop all good proceeding!
LONGAVILLE: He weeds the corn, and still lets grow the weeding
Berowne will use rhetoric later to justify other contradictory conclusions--for example, when he reasons that the courtship of the Princess and her ladies does not violate their oath (see IV.iii.286-362).
When Costard, the fool, is caught courting Jaquenetta by Don Armado, he tries to reason his way out of the punishment by arguing that Jaquenetta is not a wench but a damsel, not a damsel but a virgin, and finally not a virgin but a maid. The King, however, informs him that these classifications all fall under the same decree and punishes him anyway. The defeat of Costard's reasoning and his punishment for courting Jaquenetta warn the King and lords to avoid duplicitous rhetoric and scheming women. Unfortunately, they choose not to heed this warning, and so become entangled in similar situations again.