The minor characters, in this case Egeon and the Duke, set up the framework of the play. Egeon, at the behest of the Duke, describes his adventures and relates his life story. This provides the history of The Comedy of Errors, and helps the audience keep track of the confusion which unfolds during the play.
There are several themes that Shakespeare uses which are only loosely related to the actual comedy. The conflicts between bondage and liberty, law and sympathy, death and rebirth all form a very serious undertones within the play. There is also the serious effect time. Shakespeare requires that all the action culminate at five o'clock, with that being the time of Egeon's execution, Antipholus of Syracuse's meeting with the merchant, and the moment when Angelo must pay the Second Merchant his money.
There are also several threats within the play. The comedy opens with Egeon unwittingly breaking the law, for which he is sentenced to death. Some theaters have actually set up gallows on stage for the entire performance in order to continually remind the audience that although this is a comedy, there is always the threat of death hanging over the performance. In addition to this very real threat, there is also the threat that the play will end prematurely. At various times the characters are dangerously close to revealing the entire plot and ending the play. These occur when Antipholus has the chance to ransom his father at the beginning, and also when both Dromios are on opposite sides of the door at Adriana's house.
The play does not end prematurely, and for the simple reason that the characters are meant to learn something. For instance, the Duke claims that he is sympathetic, but that his duty is to uphold the law at all costs, which is why he sentences Egeon to die. However, the audience must remember that Egeon's death is contingent upon a thousand mark ransom. Thus, the Duke also stands to gain potential profit by sentencing Egeon to death. His pardon of Egeon at the end of the play is supposed to indicate that he has not only learned to pardon, but has overcome his selfishness by having him turn down the ransom which Antipholus offers.
The play also hinges on coincidence. When Antipholus of Syracuse arrives, the merchant pays him a thousand marks and simultaneously warns him that a Syracusan was arrested that very day. Antipholus of Syracuse therefore has the chance to immediately ransom Egeon, and be reunited with his father. But it turns out that he is too self-absorbed throughout the entire beginning, preferring instead to walk alone through the street. This actually relates to the title, since Error comes from the Latin to ³wander." Thus the play is really about wandering, and characters trying to find their true identities.
Another theme which crops up throughout the play is in the phrase, ³drop of water." Antipholus first uses the phrase to describe himself, since he views himself as a drop of water which is trying to find another drop in the vast ocean of mankind. In this case he is referring to his search for his lost brother and father. Later, Adriana uses almost identical language when referring to her husband, and compares their separation to that of separating water. Thus the phrase stands for a joining of two people, and implies an intimate bond.
The issue of primogeniture is one which Shakespeare plays with as well. this mostly appears at the end of the play when the two Dromios remain on stage. In England the eldest son always has priority, but since they are twins it is impossible to know who is eldest. Thus, the two servants decide to enter through the door together, rather than fight over who is elder. However, this issue has real historical implications. The story of Jacob and Esau, in which Jacob cheats his brother Esau out of the inheritance, is one every Christian would have known at the time. Also, there is the story of Romulus and Remus, the founders of Rome, in which one twin kills the other. Thus, although in a comic setting, the use of twins in The Comedy of Errors is not necessarily inherently humorous.
A further theme that is constantly appearing in the play is that of bondage versus liberty. Starting in the first scene, where Egeon is bound and sentenced, the concept of binding people is made manifest. It continues with Adriana, who asks her sister why men have more liberty than their wives. This culminates in the end scenes where Antipholus of Ephesus and Dromio are bound, and where Adriana demands that the Officer bind up Antipholus of Syracuse. However, the ending of the play shows a change to liberty when the Duke orders Egeon set free, and all the characters end up at liberty.
This is further played up in a humorous context by the two Dromios, who themselves are called bondsmen. Thus, when Dromio of Ephesus is bound, he turns and comments on the fact that he is now literally bound to his master.
There are two subtle concepts relating to the various beliefs about twins and sons which exist in the play. Twins used to be viewed as two separate paths which could be taken, of as a set of alternate paths. Sons were often considered to be extensions of their fathers. Thus, in the play this emerges through an analysis of the events which Egeon relates. After the shipwreck where Egeon is separated from his children, he himself becomes a split man. Where he was previously married, he is made a bachelor by the wreck. Since his sons are meant to take after him, we see that one son is married while another is still a bachelor. At the end of the play, when Egeon is reunited with his wife Emilia, both his sons also end up married (or almost, in the case of Luciana and Antipholus of Syracuse).
The gold chain must be commented on, since it represents the only object which has any significance within the play. The chain is a symbol of a negative sign of possession. It is first promised to Adriana, then to the Courtesan, neither of whom receives it. Antipholus and Angelo are both arrested because of the fact that they no longer have the chain, since it was incorrectly given to Antipholus of Syracuse. The chain also functions as a sign of money, because it hold the ability to produce pardon. Its value is enough to pardon Egeon, and Antipholus of Ephesus could also have been pardoned immediately if he had had the chain.