Answer: To acknowledge and answer criticism of a thesis
Step-by-step explanation:
A proper argumentative essay presents counterclaims, meaning the arguments someone on the opposite side of the issue might say, in order to explain why the essay´s position is still the correct one.
The purpose is to persuade the reader that the counterclaim has already been considered, and it has been found to be inadequate or fallacious. If done properly, it provides the opportunity to adress the reader's possible doubts before they are finished reading.