This study will examine the purposes and effects of Dogberry, Verges, and the Watch in Shakespeare's comedy Much Ado About Nothing. It is important to keep in mind that the play is a comedy, because the purposes and effects of these bumbling characters all focus on keeping the play a comedy. At the same time, they help avoid having an evil plot happen which would be too heavy a weight for the light foundation of the play to hold up.
These characters serve two main purposes and create two main effects. First, on the level of ideas, their very stupid self-deception serves as contrast to the more subtle self-deception of the other characters. This is especially true of the two couples linked by romance and misunderstanding. Second, on the level of the structure of the play, these characters are used by Shakespeare to blunder into discovering the plot before it could be completely carried out. This keeps the play a comedy and lets the audience know that the play is not about to become a tragedy, which it would have become if that plot had actually been carried out. The audience would not be able to relax and enjoy the comedy if it feared that at any moment it was about to turn into a bloody tragedy.
At the same time, if the officials (Dogberry, etc.) were effective, they would have stopped Don John's plot too soon, and some of the play's most comic complications would not have taken place. They serve the purpose of keeping the plot going (by not stopping Don John's plans too soon), and then they serve the purpose of bringing Don John's plans to an end before the comedy is turned into a tragedy.
It is a light comedy, then, and the main purpose and effect of these clownish characters is to keep it light, both with respect to ideas and plot. Don John is the evil character whose jealousy and desire for revenge threaten the love of the couples, the well-being and lives of his political and military foes, and the very nature and s...