On Purim we are bidden to get so thoroughly drunk on wine or other intoxicants that we are unable to distinguish between good and evil:
Rava said: one is obligated to become inebriated on Purim until he does not know (ad delo yada) the difference between "Cursed is Haman" and "Blessed is Mordechai".
While halakhists dispute the question of whether this is meant literally and whether it is halakhically required or even advisable, the notion of drinking oneself into oblivion on Purim is certainly part of the Jewish tradition, and is widely observed. The Lubavitcher Rebbe explains this unusual religious rite as follows:
Nothing created by G-d has a negative purpose… On Purim we are required to elevate our understanding to the point that we perceive no essential distinction between Mordechai and Haman. For the ultimate goal in the creation of Haman is that he become a force for good, like Mordechai… Self-transcendence is the goal of our drinking on Purim. The state which transcends the limits of reason is related to the concept of transforming evil to good. From an intellectual perspective, good and evil have clearly defined boundaries… However, the infinity of G-d's essence (and likewise, the infinite potential of our souls) is not bounded by these limitations. At this level, "darkness is like light" (Psalm 139:12).
This interpretation sees the distinction between good and evil as a function of the human perspective, rather than an absolute truth; the infinity of God's essence and the infinite potential of the human soul are "beyond good and evil", as Friedrich Nietzsche titled one of his books.
The question of whether, in an ultimate sense, God is "good", or whether he is the "all-encompassing" author of good and bad alike, has vexed religious people from the beginning of time. Some religions have a clear cut answer to the question. Jews do not, most of the year. But some Kabbalistic and Hasidic sources indicate that we do have a clear cut view on the matter twice a year: both on Yom Kippur, when we are delirious from fasting, and on Purim, when we are thoroughly drunk with alcohol, we realize that the distinction between good and evil is an illusion, and all is one with the One, God himself, the ultimate Good. That is how our sins become virtues when we repent on the Day of Atonement, and that is why we are bidden to confuse Mordechai and Haman on Purim, as suggested by the Lubavitcher Rebbe. Atonement is "at-one-ment", a realization that all is one. And Purim, the very day devoted to the triumph of Israel over the ultimate evil, Amalek, is also the day on which we are bidden to drown the distinction between Israel and Amalek, between Mordechai the Jew and Haman the Amalekite, in alcohol.
While this notion is first explicitly attested in Hasidic sources, it would seem to be much older. The statement that one is obligated to become inebriated on Purim until he does not know the difference between 'Cursed is Haman' and 'Blessed is Mordechai'" is attributed in the Talmud to the fourth-century Babylonian amora (sage) Rava. Rava himself seems to have believed that blurring the distinction between good and evil is a desideratum, and that the Ultimate is One. This can be seen as a polemic against the prevailing Zoroastrian religion in Talmudic Babylonia, which was dualistic. Zoroastrians believe that power is divided between the good god, Ahura Mazda, and the evil god, Ahriman, and it is the task of mankind to help the good god prevail over the evil one. The notion that good and evil are illusions because God is one is an apt Jewish response.
Rabbi Abraham Isaac Hakohen Kook likewise believed that this perspective is the true one. In his view, not only is the distinction between good and evil a mere human intellectual construct, but the very sense we have that God and creation are separate from one another is a limited human perspective. The absolute truth is that God and creation are one; Existence is one; there is nothing but God. The challenge of life is to try to adopt the Purim/Yom Kippur perspective all year round without resorting to a delirium induced by alcohol or fasting. Rav Kook refers to this process as teshuvah – returning to the ultimate Oneness from which we feel differentiated:
Teshuvah predated the world, and it is thus the foundation of the world. A person's life is actually perfected when it unfolds continuously in accordance with its own nature. And since nature in its own right has neither insight nor ability to distinguish, sin is inevitable in this sense, and "there is no righteous man on earth who does good and does not sin" (Ecclesiastes 7:20). However, suppressing the essential nature of life in order to make a person sinless is the greatest sin of all: "and he shall atone for him [the Naziritie, who abstains from the pleasure of wine] for his sin against his soul" (Numbers 6:11). It is teshuvah that corrects this problem and restores the world and the person's life to their origin by uncovering the life's sublime foundation, the world of freedom. And that is why the Lord is called E-lohim Hayyim, Life God [literally: "the Living God"].
This foundation of life in its own nature is perfection, the ultimate Good. The limited sense of good, as opposed to sin, that guides the sober person in his moral compass, is an illusion.
A similar idea is found in the Chinese classic Tao Te Ching. The Chinese refer to "the foundation of life in its own nature" as the Tao, the Way, and followers of the Tao seek to "do teshuvah" in Rav Kook's sense, to follow the Way back to their natural state, the way they were meant to be, as part of the One. They do so by means of what is called wu-wei, non-action. By "not doing" they accomplish the ultimate goal of mankind and all of creation, to become once again part of the undifferentiated One:
Take emptiness to the limit; maintain tranquility in the center… Things come forth in great numbers; each one returns to its root. This is called tranquility. "Tranquility" – This means to return to your fate. To return to your fate is to be constant; to know the constant is to be wise… To know the constant is to be all-encompassing; to be all-encompassing is to be impartial; to be impartial is to be kingly; to be kingly is to be like heaven; to be like heaven is to be one with the Tao… .
In terms of morality, the ideal is a return to a childlike state in which no difference between good and bad, or beautiful and ugly, is perceived:
It is only when everyone in the world recognizes the beautiful as beautiful that ugliness comes into being. It is only when everyone knows the good that the bad comes to be. For truly, "Being and Non-being grow out of one another; difficult and easy complete one another; long and short form one another; high and low determine one another; tone and voice give harmony to one another; front and back give sequence to one another". Therefore the sage dwells in non-action and practices the wordless teaching.
The only reason some things are considered ugly or bad is because other things are considered beautiful and good. Non-action and wordless teaching can bring us back to the world of the child, to whom these concepts are foreign:
By not elevating the worthy, you bring it about that people will not compete. By not valuing goods that are hard to obtain, you bring it about that people will not act like thieves… Constantly cause the people to be without knowledge and without desires.
The childlike state that precedes the distinction between opposites, referred to in this last passage as being "without knowledge", is identical to the state of intoxication we are bidden to reach on Purim (ad delo yada, "until he does not know"). This is the message of Purim. The highest good is not Mordechai as opposed to Haman; the highest good is an undifferentiated One, the foundation of the world and life in its true nature. If we can find a way to bring the childlike lack of differentiation we feel on Purim into our everyday lives, we can overcome life's obstacles and live our lives naturally, as part of the ultimate Existence, the One.
Moshe Benovitz is professor of Talmud and Rabbinics at the Schechter Institute of Jewish Studies in Jerusalem. He is the author of Kol Nidre: Studies in the Development of Rabbinic Votive Institutions (Atlanta 1998) and several volumes of comprehensive critical commentary on sections of the Talmud, as well as numerous scholarly articles on various aspects of Talmudic scholarship and rabbinic history, including oaths and vows, liturgy, and Jewish festivals.
 Talmud Bavli, Megillah 7b.
 See David Golinkin, "To Drink or not to Drink", http://www.schechter.edu/insightIsrael.aspx?ID=28.
 Summary of Likutei Sichos 7, Vayikra 3 in http://livingjewish.net/chassidus-page/a-mitzvah-to-drink.
 See Tiqqunei Zohar 21 (42b); Shifra Epstein, “The ‘Drinking Banquet’ (Trink-Siyde): A Hassidic Event for Purim”, Poetics Today 15 (1994), pp. 135-136, and sources mentioned there.
 Talmud Bavli, Yoma 86b, in the name of Resh Laqish.
 See the Oxford English Dictionary, s.v. "atonement", and references cited there.
 Of course, this derivation is only true of the English word; the Hebrew word kippur is derived from a root that indicates covering up. However, in essence, covering up a stain or blemish is also a way of reintegrating it with the whole.
 A.I. Kook, Shemonah Qevatsim 1:787-789.
 A.I. Kook, Orot Hateshuvah 5:6*.
 Tao Te Ching 16. The translations are based on that of Robert G. Henricks, Te Tao Ching, New York 1989, with modifications based on other translations.
 Tao Te Ching, 2.
 Tao Te Ching, 3.