In The Merchant of Venice, the theme of appearance and reality is prominent because many of the characters are not what they seem and their actions are sometimes contradictory to their seemingly honest motives. Furthermore, the caskets that hold the secret to a successful marriage to Portia mislead her suitors and they choose poorly.
1. Shylock appears to be willing to loan money to Antonio even though he "hates him for he is a Christian" (I.iii.37). However, the penalty if Antonio cannot repay him is unreasonable and whereas it is not taken literally by the Christians, it is meant literally by Shylock when he demands his "pound of flesh."
2. Antonio appears to be virtuous and generous. He loves his friends and has a good reputation. Yet he treats Shylock very badly simply because he is a Jew which makes him a hypocrite. Shylock reminds the reader that it is Antonio's double standards that have led to this situation. Shylock refers to "the villainy you teach me" in Act III, scene i, line 61 meaning that Christians like Antonio are responsible for the animosity (hatred) between them.
3. Portia's suitors must choose from three caskets of gold, silver and lead if they desire to marry her. Portia is relieved that most of her suitors to date have chosen foolishly as they have been misled by the words which describe the contents of the caskets. Only one has Portia's portrait inside but so far the suitors have not realized that there is a warning contained in the words that read "All that glisters is not gold" (II.vii.65). Only Bassanio will choose wisely and there is still debate as to whether Portia guides his choice (which would be forbidden by her father's will) or whether he makes his own considered choice.
4. Even Jessica fools her father and runs away with his precious ring, selling it and therefore revealing that she has no respect for Shylock.
5. The actions of the characters have been quite selfish and the theme of appearance versus reality has shown these traits but Portia will show great "mercy" and compassion when she disguises herself and helps Antonio avoid what would have been certain death if he had allowed Shylock to take his bond of a "pound of flesh."
Shakespeare then reveals the theme through character development and this helps drive the plot and subplots forward.