Jewish atheism refers to atheism as practiced by people who are ethnically, and to some extent culturally, Jewish. Because Jewishness encompasses ethnic as well as religious components, the term "Jewish atheism" does not necessarily imply a contradiction. Based on Jewish law's emphasis on matrilineal descent, even religiously conservative Orthodox Jewish authorities would accept an atheist born to a Jewish mother as fully Jewish.
Organized Jewish life 
There has been a phenomenon of atheistic and secular Jewish organizations, mostly in the past century, from the Jewish socialist Bund in early twentieth-century Poland to the modern Society for Humanistic Judaism in the United States. Many Jewish atheists feel comfortable within any of the three major non-Orthodox Jewish denominations (Reform, Conservative, and Reconstructionist). This presents less of a contradiction than might first seem apparent, given Judaism's emphasis on practice over belief, with even mainstream guides to Judaism suggesting that belief in God is not a necessary prerequisite to Jewish observance. However, Orthodox Judaism regards the acceptance of the "Yoke of Heaven" (the sovereignty of the God of Israel in the world and the divine origin of the Torah) as a fundamental obligation for Jews. Even among non-Orthodox Jews, espousing atheism remains problematic outside of the Society for Humanistic Judaism. The Reform movement, for example, has rejected efforts at affiliation by atheistic temples. The presence of atheists in all denominations of modern Judaism, from Secular Humanistic Judaism to Orthodoxy, has been noted.
Jewish theology 
Much recent Jewish theology makes few if any metaphysical claims and is thus compatible with atheism on an ontological level. The founder of Reconstructionist Judaism, Mordechai Kaplan, espoused a naturalistic definition of God, while some post-Holocaust theology has also eschewed a personal God. The Jewish philosopher Howard Wettstein has advanced a non-metaphysical approach to religious commitment, according to which metaphysical theism-atheism is not the issue.  Harold Schulweis, a Conservative rabbi trained in the Reconstructionist tradition, has argued that Jewish theology should move from a focus on God to an emphasis on "godliness." This "predicate theology", while continuing to use theistic language, again makes few metaphysical claims that non-believers would find objectionable.
However, some Jewish atheists remain deeply uncomfortable with the use of any kind of theistic language. For such Jews traditional practice and symbolism can still retain powerful meaning. They may continue to engage in Jewish rituals such as the lighting of Shabbat candles and find meaning in many aspects of Jewish culture and religion. For example, to an atheist Jew, the Menorah might represent the power of the Jewish spirit or stand as a symbol of the fight against assimilation. No mention of a divine force in Jewish history would be accepted literally; the Torah may be viewed as a common mythology of the Jewish people, not a faith document or correct history.
Secular Jewish culture 
Many Jewish atheists would reject even this level of ritualized and symbolic identification, instead embracing a thoroughgoing secularism and basing their Jewishness entirely in ethnicity and secular Jewish culture. Possibilities for secular Jewishness include an identification with Jewish history and peoplehood, immersion in Jewish literature (including such non-religious Jewish authors as Philip Roth and Amos Oz), the consumption of Jewish food and an attachment to Jewish languages such as Yiddish, Hebrew or Ladino. A high percentage of Israelis identify themselves as secular, rejecting the practice of the Jewish religion (see Religion in Israel). While some non-believers of Jewish ancestry do not consider themselves Jews, preferring to define themselves solely as atheists, Judaism is arguably a culture and tradition that one can easily embrace without religious faith.
Notable people 
A number of well-known Jews throughout history have rejected a belief in God. Some have denied the existence of a traditional deity while continuing to use religious language. In 1656 the seventeenth-century Jewish philosopher Baruch Spinoza was excommunicated by Amsterdam's Sephardic synagogue after advancing a pantheist notion of God that, according to some observers, is both compatible with and paved the way for modern atheism. Deeply influenced by Spinoza, Albert Einstein used theistic language and identified strongly as a Jew, while rejecting the notion of a personal god. The astrophysicist Carl Sagan was born into a Jewish family and was a non-theist.
Karl Marx was born into an ethnically Jewish family but raised as a Lutheran, and is among the most notable and influential atheist thinkers of modern history; he developed dialectical and historical materialism which became the basis for his critique of capitalism and his theories of scientific socialism. Marx became a major influence among other prominent Jewish intellectuals including Moses Hess. In one of his most cited comments on religion he stated: "Religion is the sigh of the oppressed creature, the heart of a heartless world, and the soul of soulless conditions. It is the opium of the people".
Many other famous Jews have wholeheartedly embraced atheism, rejecting religiosity altogether. Sigmund Freud penned The Future of an Illusion, in which he both eschewed religious belief and outlined its origins and prospects. At the same time he urged a Jewish colleague to raise his son within the Jewish religion, arguing that "If you do not let your son grow up as a Jew, you will deprive him of those sources of energy which cannot be replaced by anything else." The anarchist Emma Goldman was born to an Orthodox Jewish family and rejected belief in God, while the Israeli prime minister Golda Meir, when asked if she believed in God, answered "I believe in the Jewish people, and the Jewish people believe in God." More recently, the French Jewish philosopher Jacques Derrida stated somewhat cryptically, "I rightly pass for an atheist". In the world of entertainment, Woody Allen has made a career out of the tension between his Jewishness and religious doubt ("How can I believe in God when just last week I got my tongue caught in the roller of an electric typewriter?").
See also 
- Conversion to Judaism
- Christianity and Judaism
- Jews in apostasy
- Humanistic Judaism
- Schisms among the Jews
- Who is a Jew?
- What Makes a Jew "Jewish"? – Jewish Identity
- See, for example: Daniel Septimus, Must a Jew Believe in God?
- "Reform Jews Reject a Temple Without God", New York Times, June 13, 1994.
- See, for example, Mordechai Kaplan, The Meaning of God in Modern Jewish Religion (New York: Behrman’s Jewish book house, 1937); Richard Rubenstein, After Auschwitz: Radical Theology and Contemporary Judaism (Indianapolis: Bobbs-Merrill, 1966).
- Howard Wettstein, The Significance of Religious Experience (Oxford University Press, 2012)
- See Harold M. Schulweis. Evil and the Morality of God (Cincinnati: Hebrew Union College Press, 1984); For Those Who Can't Believe : Overcoming the Obstacles to Faith (Harper Perennial, 1995).
- An example of an atheist rejecting Jewish identification is cited in "Hipster Antisemitism," Zeek, January 2005
- Christopher Hitchens, ed., The Portable Atheist (Philadelphia: Da Capo Press, 2007), 21.
- "The Religious Non-believer: Einstein and his God", Moment, April 2007.
- Sagan, Carl (February 12, 1986). "Chapter 23". Broca's Brain: Reflections on the Romance of Science. Ballantine Books. p. 330. ISBN 0-345-33689-5.
- David S. Ariel, What Do Jews Believe? (New York: Shocken Books, 1995), 248.
- See Emma Goldman, "The Philosophy of Atheism," in Christopher Hitchens, ed., The Portable Atheist (Philadelphia: Da Capo Press, 2007), 129–33; Golda Meir is quoted by Jonathan Rosen in "So Was It Odd of God?", The New York Times, December 14, 2003.
- Obituary for Jacques Derrida, Chronicle of Higher Education, 10/11/2004
- Woody Allen Quotes – The Quotations Page