A Book By Any Other Cover
Don't judge a book by its cover. Or by the costume it wears. If we didn't know better, we might think Purim was a frivolous holiday. It is not as strict as Shabbat or the major holidays, so live music, driving and texting (not at the same time please) are permitted. Plus, we do many things that we usually don't do on Jewish holidays. Everyone dresses in ridiculous costumes, we boo, make noise and cheer in synagogue, and have lavish feasts in which alcohol consumption is usually encouraged. We put on special sitcoms/roasts called Purim shpiels and deliver ersatz words of Torah, called Purim Torah. But frivolity is only the outer sense of the holiday; the inner sense is far more profound.
If we didn't know better, we might think that the the Scroll of Esther (Megillat Esther) is just a light-hearted piece of melodramatic fluff, with a beautiful heroine, a dastardly villain, a courageous hero and a silly king. It has plenty of slapstick, unlikely coincidences and the villain's undoing is truly theatric and enjoyable. Almost every time that Haman is mentioned, he is called "the enemy of the Jews" and every time Mordecai is mentioned, he is called "The Jew", as if to say that they are one-dimensional set pieces. But, the megilla may be trying - and maybe too hard - to seem like it's nothing serious. Underneath its light-hearted exterior may be more than meets the eye. Animal Farm was not just a cute book about talking pigs either, right?
If we didn't know better, we might think that the custom of dressing up in costume on Purim is just a silly custom that Jews developed. We might think that they just wanted to take their minds off the relentless anti-semitism of their day or were mimicking passion plays and other kinds of medieval theatre. But just as dressing up hides the identity of the one in costume, so too the custom of dressing up may have deeper roots and meanings as well.
Dressing up in costume has never been just for children. Of course, children enjoy it and children's Purim carnival and costume parade are ubiquitous elements of an American Purim. But adults have always dressed up as well. In Venetian balls, masks in particular created a high drama, in which everyone tried to guess who was who. In the American milieu, Halloween costumes are often used to create an alternative identity, one that is not responsible for its actions and is freed from inhibitions. What happens on Halloween stays in Halloween. Lastly, people may go in costume because they are not happy with who they are and are ashamed of their true identities.
They are hiding themselves. None of these are good Jewish reasons for getting dressed up. But adults have always dressed up on Purim as well and I have catalogued eight to ten other Jewish (and source-based) reasons why we dress up on Purim. I will share one with you.
Esther was just a young suburban Jewish girl raised by her uncle, when she is suddenly catapulted to fame and fortune by being selected as the Queen of Persia. Who would have thought that she could do that? But - even after becoming queen - Esther continues in disguise, for she does not reveal her Jewish identity. Haman apparently doesn't know, because he is completely blindsided by her revelation that she is Jewish at the intimate banquet he attends with the king and queen. Moreover, Esther was 'hidden' from Haman in other ways - he never tries to recruit her as an ally and he never seems to identify her as a threat or rival. Who would have thought that the beauty queen virgin bride chosen by Achashverosh might actually have been smart enough and shrewd enough to outwit him all along?
Esther is perhaps underestimated by Mordechai as well. When she is first taken to the palace, he seems to feel that he needs to check up on her every day and that she should do exactly as he commanded her. But there comes a time when she not only stops taking his orders, but starts telling HIM what has to be done. Who would have thought that his little niece Esther could have concocted the plan that would save the Jews? She may even have been underestimated by the great Rabbis of her age, who did not want to include her book (the scroll of Esther) among the holy books of the Jewish canon or her holiday among the special days of Israel. But she does not let the matter rest. After Mordecai has already tried and failed to gain full acceptance for Purim (Esther 9:20), she instructs them "kitvuni l'dorot", "write me (i.e. my book) for all generations." And they accede to her request, for Esther is one of our holy books.
In other words, Esther was a surprise heroine. No one even saw her coming! Not Achashverosh, not Haman, not even Mordecai and the Rabbis. More than that, she was an unlikely heroine. The sweet little girl that everyone liked turned out to be so much more than she appeared. Her true value was hidden - disguised - until the time when it was meant to be revealed.
This idea is mentioned as a general principle in Pirkei Avot (Ethics of the Fathers 4:20). Regarding where one may find wisdom, "Rebbe said: Do not look at the container, but what is in it: there may be a new container with fine old wine and a fine old container that does not even have [immature] wine in it." Though Rebbe is suggesting that you should not assume that an old and venerable person is automatically wise or that a young 'un lacks wisdom, his point is broadly applicable to the assumptions we make about other people. We sometimes think we know a lot about someone based on their appearance, their sex, their age, their job or their ethnicity. But people surprise us all the time. The fine, educated, cultured Germans perpetrated the worst atrocities of the 20th century without even messing up their hair. And the hobo down the street can sometimes be more kind, honest and friendly than the upscale urbanites who walk by him. The non-practicing Jew who doesn't even know what Purim is may be nurturing a nascent spirituality that is looking for a path to break out, while the yeshiva boy may be struggling to believe in God. Sometimes, a great teacher comes across as bland and uninspiring, but the innocent conviction of a five year-old can pierce the hearts of humans and angels.
So, perhaps we dress up in costume on Purim not for ourselves, but for others. By changing our look, we remind others that they should break down their assumptions about us and see us in a new light. It is an opportunity to see a person with different eyes, to find wisdom, courage and religiosity in people where we hadn't thought to look. Whatever the costume is, it should remind us that with a quick wardrobe change, everything can seem different. Perhaps we have made assumptions about others that need to be revisited.
There are two important caveats to this. One, we should choose carefully how we present ourselves. When a woman dresses the part of a slut or man the part of a pimp, what are they saying about themselves or their values? When people act out their new roles - especially if there is also alcohol involved -- how do they behave? Surely, they are saying "oh this is all in good fun. It's just a joke." And maybe it is. But if we are asking people to think differently about us, this is not what we want them to think. I thought that girl was really nice, but from now on I will just think of her as a sexual object. I thought that guy was sensitive and charming, but now I see that he has a meaner side to his personality. We want to reveal what is good about us, not what is ugly. When a usually buttoned-down Rabbi dresses in an outrageous costume once a year, he may be seeking to be more funny and approachable to his students. But he does not want them to think that he is an idiot or someone who we thought we could respect, but now we have to wonder.
The second caveat is that we should look for the good in other's costumes. We are not here to 'judge' whether or not a costume is good or not, but to celebrate the opportunity to see a new side of our friends. In theory, then, all the girls should dress as Esther and all the boys as Mordechai. In theory, all of us should dress as a Jewish hero or heroine. A scholar, a leader, a savior, a pioneer, a teacher. Our choices should reflect our values. In practice, we don't do this and opt for the creativity and fun of choosing celebrities or fictional characters. So, all we are left with is the principle of the matter, which we can at least carry with us into Purim. Not everyone is just what they appear. Perhaps there is more in all of us than Haman would have thought. A freilichen Purim!
 According to this theory, dressing up derives from the original Purim shpiels, which were actual plays, with full costumes.
 Of course, it was a very relevant piece of information, since he had just announced his plans to kill all Jews. He becomes transformed instantaneously into someone trying to kill the queen as well, which leads shortly thereafter to his execution.
 Talmud, Megilla 7a. The Rabbis felt that no more books should be added to the canon and that they days of prophecy or divine inspiration had ceased. (Maharatz Chayot) But Esther apparently convinced them using sophisticated Halachic arguments and the content of the book that it was deserving of being canonized.