Search This Blog

Sunday, August 24, 2014

Judaism

Judaism

From Wikipedia, the free encyclopedia

Judaica (clockwise from top): Shabbat candlesticks, handwashing cup, Chumash and Tanakh, Torah pointer, shofar and etrog box

Judaism (from the Latin Iudaismus, derived from the Greek Ἰουδαϊσμός, and ultimately from the Hebrew יהודה, Yehudah, "Judah";[1][2] in Hebrew: יהדות, Yahadut, the distinctive characteristics of the Judean ethnos)[3] is the religion, philosophy and way of life of the Jewish people.[4] Judaism is a monotheistic religion, with the Torah as its foundational text (part of the larger text known as the Tanakh or Hebrew Bible), and supplemental oral tradition represented by later texts such as the Mishnah and the Talmud. Judaism is considered by religious Jews to be the expression of the covenantal relationship God established with the Children of Israel.[5]

Judaism includes a wide corpus of texts, practices, theological positions, and forms of organization. Within Judaism there are a variety of movements, most of which emerged from Rabbinic Judaism, which holds that God revealed his laws and commandments to Moses on Mount Sinai in the form of both the Written and Oral Torah.[6] Historically, this assertion was challenged by various groups such as the Sadducees and Hellenistic Judaism during the Second Temple period; the Karaites and Sabbateans during the early and later medieval period;[7] and among segments of the modern reform movements. Liberal movements in modern times such as Humanistic Judaism may be nontheistic.[8] Today, the largest Jewish religious movements are Orthodox Judaism (Haredi Judaism and Modern Orthodox Judaism), Conservative Judaism and Reform Judaism. Major sources of difference between these groups are their approaches to Jewish law, the authority of the Rabbinic tradition, and the significance of the State of Israel.[9] Orthodox Judaism maintains that the Torah and Jewish law are divine in origin, eternal and unalterable, and that they should be strictly followed. Conservative and Reform Judaism are more liberal, with Conservative Judaism generally promoting a more "traditional" interpretation of Judaism's requirements than Reform Judaism. A typical Reform position is that Jewish law should be viewed as a set of general guidelines rather than as a set of restrictions and obligations whose observance is required of all Jews.[10][11] Historically, special courts enforced Jewish law; today, these courts still exist but the practice of Judaism is mostly voluntary.[12] Authority on theological and legal matters is not vested in any one person or organization, but in the sacred texts and rabbis and scholars who interpret them.[13]

Judaism claims a historical continuity spanning more than 3,000 years. Judaism has its roots as a structured religion in the Middle East during the Bronze Age.[14] Of the major world religions, Judaism is considered one of the oldest monotheistic religions.[15][16] The Hebrews / Israelites were already referred to as "Jews" in later books of the Tanakh such as the Book of Esther, with the term Jews replacing the title "Children of Israel".[17] Judaism's texts, traditions and values strongly influenced later Abrahamic religions, including Christianity, Islam and the Baha'i Faith.[18][19] Many aspects of Judaism have also directly or indirectly influenced secular Western ethics and civil law.[20]

Jews are an ethnoreligious group[21] and include those born Jewish and converts to Judaism. In 2012, the world Jewish population was estimated at about 14 million, or roughly 0.2% of the total world population.[22] About 42% of all Jews reside in Israel and about 42% reside in the United States and Canada, with most of the remainder living in Europe, and other minority groups spread throughout the world in South America, Asia, Africa, and Australia.[23]

Defining character and principles of faith

Defining character

Glass platter inscribed with the Hebrew word zokhreinu - remember us
A 19th-century silver Macedonian Hanukkah menorah

Unlike other ancient Near Eastern gods, the Hebrew God is portrayed as unitary and solitary; consequently, the Hebrew God's principal relationships are not with other gods, but with the world, and more specifically, with the people He created.[24] Judaism thus begins with an ethical monotheism: the belief that God is one, and concerned with the actions of humankind.[25] According to the Tanakh (Hebrew Bible), God promised Abraham to make of his offspring a great nation.[26] Many generations later, he commanded the nation of Israel to love and worship only one God; that is, the Jewish nation is to reciprocate God's concern for the world.[27] He also commanded the Jewish people to love one another; that is, Jews are to imitate God's love for people.[28] These commandments are but two of a large corpus of commandments and laws that constitute this covenant, which is the substance of Judaism.

Thus, although there is an esoteric tradition in Judaism (Kabbalah), Rabbinic scholar Max Kadushin has characterized normative Judaism as "normal mysticism", because it involves everyday personal experiences of God through ways or modes that are common to all Jews.[29] This is played out through the observance of the halakhot and given verbal expression in the Birkat Ha-Mizvot, the short blessings that are spoken every time a positive commandment is to be fulfilled.
The ordinary, familiar, everyday things and occurrences, we have constitute occasions for the experience of God. Such things as one's daily sustenance, the very day itself, are felt as manifestations of God's loving-kindness, calling for the Berakhot. Kedushah, holiness, which is nothing else than the imitation of God, is concerned with daily conduct, with being gracious and merciful, with keeping oneself from defilement by idolatry, adultery, and the shedding of blood. The Birkat Ha-Mitzwot evokes the consciousness of holiness at a rabbinic rite, but the objects employed in the majority of these rites are non-holy and of general character, while the several holy objects are non-theurgic. And not only do ordinary things and occurrences bring with them the experience of God. Everything that happens to a man evokes that experience, evil as well as good, for a Berakah is said also at evil tidings. Hence, although the experience of God is like none other, the occasions for experiencing Him, for having a consciousness of Him, are manifold, even if we consider only those that call for Berakot.[30]
Whereas Jewish philosophers often debate whether God is immanent or transcendent, and whether people have free will or their lives are determined, Halakha is a system through which any Jew acts to bring God into the world.

Ethical monotheism is central in all sacred or normative texts of Judaism. However, monotheism has not always been followed in practice. The Jewish Bible (Tanakh) records and repeatedly condemns the widespread worship of other gods in ancient Israel.[31] In the Greco-Roman era, many different interpretations of monotheism existed in Judaism, including the interpretations that gave rise to Christianity.[32]

Moreover, as a non-creedal religion, some have argued that Judaism does not require one to believe in God. For some, observance of Jewish law is more important than belief in God per se.[33] In modern times, some liberal Jewish movements do not accept the existence of a personified deity active in history.[34]

Core tenets

Scholars throughout Jewish history have proposed numerous formulations of Judaism's core tenets, all of which have met with criticism.[35] The most popular formulation is Maimonides' thirteen principles of faith, developed in the 12th century. According to Maimonides, any Jew who rejects even one of these principles would be considered an apostate and a heretic.[36][37] Jewish scholars have held points of view diverging in various ways from Maimonides' principles.[38][39]
In Maimonides' time, his list of tenets was criticized by Hasdai Crescas and Joseph Albo. Albo and the Raavad argued that Maimonides' principles contained too many items that, while true, were not fundamentals of the faith.

Along these lines, the ancient historian Josephus emphasized practices and observances rather than religious beliefs, associating apostasy with a failure to observe Jewish law and maintaining that the requirements for conversion to Judaism included circumcision and adherence to traditional customs. Maimonides' principles were largely ignored over the next few centuries.[40] Later, two poetic restatements of these principles ("Ani Ma'amin" and "Yigdal") became integrated into many Jewish liturgies,[41][citation needed] leading to their eventual near-universal acceptance.[42][43]

In modern times, Judaism lacks a centralized authority that would dictate an exact religious dogma.[13][44] Because of this, many different variations on the basic beliefs are considered within the scope of Judaism.[38] Even so, all Jewish religious movements are, to a greater or lesser extent, based on the principles of the Hebrew Bible and various commentaries such as the Talmud and Midrash. Judaism also universally recognizes the Biblical Covenant between God and the Patriarch Abraham as well as the additional aspects of the Covenant revealed to Moses, who is considered Judaism's greatest prophet.[38][45][46][47][48] In the Mishnah, a core text of Rabbinic Judaism, acceptance of the Divine origins of this covenant is considered an essential aspect of Judaism and those who reject the Covenant forfeit their share in the World to Come.[49]

Jewish religious texts

The following is a basic, structured list of the central works of Jewish practice and thought.

Jewish legal literature

The basis of Jewish law and tradition (halakha) is the Torah (also known as the Pentateuch or the Five Books of Moses). According to rabbinic tradition there are 613 commandments in the Torah. Some of these laws are directed only to men or to women, some only to the ancient priestly groups, the Kohanim and Leviyim (members of the tribe of Levi), some only to farmers within the Land of Israel. Many laws were only applicable when the Temple in Jerusalem existed, and fewer than 300 of these commandments are still applicable today.[citation needed]
While there have been Jewish groups whose beliefs were claimed to be based on the written text of the Torah alone (e.g., the Sadducees, and the Karaites), most Jews believed in what they call the oral law. These oral traditions were transmitted by the Pharisee sect of ancient Judaism, and were later recorded in written form and expanded upon by the rabbis.

Rabbinic Judaism (which derives from the Pharisees) has always held that the books of the Torah (called the written law) have always been transmitted in parallel with an oral tradition. To justify this viewpoint, Jews point to the text of the Torah, where many words are left undefined, and many procedures mentioned without explanation or instructions; this, they argue, means that the reader is assumed to be familiar with the details from other, i.e., oral, sources. This parallel set of material was originally transmitted orally, and came to be known as "the oral law".

By the time of Rabbi Judah haNasi (200 CE), after the destruction of Jerusalem, much of this material was edited together into the Mishnah. Over the next four centuries this law underwent discussion and debate in both of the world's major Jewish communities (in Israel and Babylonia), and the commentaries on the Mishnah from each of these communities eventually came to be edited together into compilations known as the two Talmuds. These have been expounded by commentaries of various Torah scholars during the ages.

Halakha, the rabbinic Jewish way of life, then, is based on a combined reading of the Torah, and the oral tradition - the Mishnah, the halakhic Midrash, the Talmud and its commentaries. The Halakha has developed slowly, through a precedent-based system. The literature of questions to rabbis, and their considered answers, is referred to as responsa (in Hebrew, Sheelot U-Teshuvot.) Over time, as practices develop, codes of Jewish law are written that are based on the responsa; the most important code, the Shulchan Aruch, largely determines Orthodox religious practice today.

Jewish philosophy

Jewish philosophy refers to the conjunction between serious study of philosophy and Jewish theology. Major Jewish philosophers include Solomon ibn Gabirol, Saadia Gaon, Judah Halevi, Maimonides, and Gersonides. Major changes occurred in response to the Enlightenment (late 18th to early 19th century) leading to the post-Enlightenment Jewish philosophers. Modern Jewish philosophy consists of both Orthodox and non-Orthodox oriented philosophy. Notable among Orthodox Jewish philosophers are Eliyahu Eliezer Dessler, Joseph B. Soloveitchik, and Yitzchok Hutner. Well-known non-Orthodox Jewish philosophers include Martin Buber, Franz Rosenzweig, Mordecai Kaplan, Abraham Joshua Heschel, Will Herberg, and Emmanuel Lévinas.

Related Topics

Rabbinic hermeneutics

13 Principles of Hermeneutics:
  1. A law that operates under certain conditions will surely be operative in other situations where the same conditions are present in a more acute form
  2. A law operating in one situation will also be operative in another situation, if the text characterizes both situations in identical terms.
  3. A law that clearly expresses the purpose it was meant to serve will also apply to other situations where the identical purpose may be served.
  4. When a general rule is followed by illustrative particulars, only those particulars are to be embraced by it.
  5. A law that begins with specifying particular cases, and then proceeds to an all-embracing generalization, is to be applied to particulars cases not specified but logically falling into the same generalization.
  6. A law that begins with a generalization as to its intended applications, then continues with the specification of particular cases, and then concludes with a restatement of the generalization, can be applied only to the particular cases specified.
  7. The rules about a generalization being followed or preceded by specifying particulars (rules 4 and 5) will not apply if it is apparent that the specification of the particular cases or the statement of the generalization is meant purely for achieving a greater clarity of language.
  8. A particular case already covered in a generalization that is nevertheless treated separately suggests that the same particularized treatment be applied to all other cases which are covered in that generalization.
  9. A penalty specified for a general category of wrong-doing is not to be automatically applied to a particular case that is withdrawn from the general rule to be specifically prohibited, but without any mention of the penalty.
  10. A general prohibition followed by a specified penalty may be followed by a particular case, normally included in the generalization, with a modification in penalty, either toward easing it or making it more severe.
  11. A case logically falling into a general law but treated separately remains outside the provisions of the general law except in those instances where it is specifically included in them.
  12. Obscurities in Biblical texts may be cleared up from the immediate context or from subsequently occurring passages
  13. Contradictions in Biblical passages may be removed through the mediation of other passages.
Orthodox and many other Jews do not believe that the revealed Torah consists solely of its written contents, but of its interpretations as well. The study of Torah (in its widest sense, to include both poetry, narrative, and law, and both the Hebrew Bible and the Talmud) is in Judaism itself a sacred act of central importance. For the sages of the Mishnah and Talmud, and for their successors today, the study of Torah was therefore not merely a means to learn the contents of God's revelation, but an end in itself. According to the Talmud,
These are the things for which a person enjoys the dividends in this world while the principal remains for the person to enjoy in the world to come; they are: honoring parents, loving deeds of kindness, and making peace between one person and another. But the study of the Torah is equal to them all. (Talmud Shabbat 127a).
In Judaism, "the study of Torah can be a means of experiencing God".[52] Reflecting on the contribution of the Amoraim and Tanaim to contemporary Judaism, Professor Jacob Neusner observed:
The rabbi's logical and rational inquiry is not mere logic-chopping. It is a most serious and substantive effort to locate in trivialities the fundamental principles of the revealed will of God to guide and sanctify the most specific and concrete actions in the workaday world .... Here is the mystery of Talmudic Judaism: the alien and remote conviction that the intellect is an instrument not of unbelief and desacralization but of sanctification."[53]
To study the Written Torah and the Oral Torah in light of each other is thus also to study how to study the word of God.

In the study of Torah, the sages formulated and followed various logical and hermeneutical principles. According to David Stern, all Rabbinic hermeneutics rest on two basic axioms:
first, the belief in the omnisignificance of Scripture, in the meaningfulness of its every word, letter, even (according to one famous report) scribal flourish; second, the claim of the essential unity of Scripture as the expression of the single divine will.[54]
These two principles make possible a great variety of interpretations. According to the Talmud,
A single verse has several meanings, but no two verses hold the same meaning. It was taught in the school of R. Ishmael: 'Behold, My word is like fire—declares the Lord—and like a hammer that shatters rock' (Jer 23:29). Just as this hammer produces many sparks (when it strikes the rock), so a single verse has several meanings." (Talmud Sanhedrin 34a).
Observant Jews thus view the Torah as dynamic, because it contains within it a host of interpretations[55]

According to Rabbinic tradition, all valid interpretations of the written Torah were revealed to Moses at Sinai in oral form, and handed down from teacher to pupil (The oral revelation is in effect coextensive with the Talmud itself). When different rabbis forwarded conflicting interpretations, they sometimes appealed to hermeneutic principles to legitimize their arguments; some rabbis claim that these principles were themselves revealed by God to Moses at Sinai.[56]

Thus, Hillel called attention to seven commonly used hermeneutical principles in the interpretation of laws (baraita at the beginning of Sifra); R. Ishmael, thirteen (baraita at the beginning of Sifra; this collection is largely an amplification of that of Hillel).[57] Eliezer b. Jose ha-Gelili listed 32, largely used for the exegesis of narrative elements of Torah. All the hermeneutic rules scattered through the Talmudim and Midrashim have been collected by Malbim in Ayyelet ha-Shachar, the introduction to his commentary on the Sifra. Nevertheless, R. Ishmael's 13 principles are perhaps the ones most widely known; they constitute an important, and one of Judaism's earliest, contributions to logic, hermeneutics, and jurisprudence.[58] Judah Hadassi incorporated Ishmael's principles into Karaite Judaism in the 12th century.[59] Today R. Ishmael's 13 principles are incorporated into the Jewish prayer book to be read by observant Jews on a daily basis.[60][61][62][63]

Jewish identity

Origin of the term "Judaism"

A mezuzah

The term Judaism derives from the Latin Iudaismus, derived from the Greek Ιουδαϊσμός Ioudaïsmos, and ultimately from the Hebrew יהודה, Yehudah, "Judah";[64][65] in Hebrew: יַהֲדוּת, Yahadut. It first appears as the Hellenistic Greek iudaismos in 2nd Maccabees in the 2nd century BCE. In the context of the age and period it held the meaning of seeking or forming part of a cultural entity, that of iudea, the Greek derivative of Persian Yehud, and can be compared with hellenismos, meaning acceptance of Hellenic cultural norms (the conflict between iudaismos and hellenismos lay behind the Maccabeean revolt and hence the invention of the term iudaismos).[66] The earliest instance of the term in English, used to mean "the profession or practice of the Jewish religion; the religious system or polity of the Jews", is Robert Fabyan's The newe cronycles of Englande and of Fraunce a 1513. As an English translation of the Latin, the first instance in English is a 1611 translation of the Apocrypha (Deuterocanon in Catholic and Orthodox Christianity), 2 Macc. ii. 21 "Those that behaved themselues manfully to their honour for Iudaisme."[67]

Distinction between Jews as a people and Judaism

According to Daniel Boyarin, the underlying distinction between religion and ethnicity is foreign to Judaism itself, and is one form of the dualism between spirit and flesh that has its origin in Platonic philosophy and that permeated Hellenistic Judaism.[68] Consequently, in his view, Judaism does not fit easily into conventional Western categories, such as religion, ethnicity, or culture. Boyarin suggests that this in part reflects the fact that much of Judaism's more than 3,000-year history predates the rise of Western culture and occurred outside the West (that is, Europe, particularly medieval and modern Europe). During this time, Jews have experienced slavery, anarchic and theocratic self-government, conquest, occupation, and exile; in the Diasporas, they have been in contact with and have been influenced by ancient Egyptian, Babylonian, Persian, and Hellenic cultures, as well as modern movements such as the Enlightenment (see Haskalah) and the rise of nationalism, which would bear fruit in the form of a Jewish state in the Levant. They also saw an elite convert to Judaism (the Khazars), only to disappear as the centers of power in the lands once occupied by that elite fell to the people of Rus and then the Mongols. Thus, Boyarin has argued that "Jewishness disrupts the very categories of identity, because it is not national, not genealogical, not religious, but all of these, in dialectical tension."[69]

In contrast to this point of view, practices such as Humanistic Judaism reject the religious aspects of Judaism, while retaining certain cultural traditions.

Who is a Jew?

According to traditional Jewish Law, a Jew is anyone born of a Jewish mother or converted to Judaism in accordance with Jewish Law. American Reform Judaism and British Liberal Judaism accept the child of one Jewish parent (father or mother) as Jewish if the parents raise the child with a Jewish identity. All mainstream forms of Judaism today are open to sincere converts, although conversion has traditionally been discouraged since the time of the Talmud. The conversion process is evaluated by an authority, and the convert is examined on his or her sincerity and knowledge.[70] Converts are given the name "ben Abraham" or "bat Abraham", (son or daughter of Abraham).
Traditional Judaism maintains that a Jew, whether by birth or conversion, is a Jew forever. Thus a Jew who claims to be an atheist or converts to another religion is still considered by traditional Judaism to be Jewish. According to some sources, the Reform movement has maintained that a Jew who has converted to another religion is no longer a Jew,[71][72] and the Israeli Government has also taken that stance after Supreme Court cases and statutes.[73] However, the Reform movement has indicated that this is not so cut and dry, and different situations call for consideration and differing actions. For example, Jews who have converted under duress may be permitted to return to Judaism "without any action on their part but their desire to rejoin the Jewish community" and "A proselyte who has become an apostate remains, nevertheless, a Jew". (p. 100-106).[74]

The question of what determines Jewish identity in the State of Israel was given new impetus when, in the 1950s, David Ben-Gurion requested opinions on mihu Yehudi ("who is a Jew") from Jewish religious authorities and intellectuals worldwide in order to settle citizenship questions. This is still not settled, and occasionally resurfaces in Israeli politics.

Jewish demographics

The total number of Jews worldwide is difficult to assess because the definition of "who is a Jew" is problematic; not all Jews identify themselves as Jewish, and some who identify as Jewish are not considered so by other Jews. According to the Jewish Year Book (1901), the global Jewish population in 1900 was around 11 million. The latest available data is from the World Jewish Population Survey of 2002 and the Jewish Year Calendar (2005). In 2002, according to the Jewish Population Survey, there were 13.3 million Jews around the world. The Jewish Year Calendar cites 14.6 million. Jewish population growth is currently near zero percent, with 0.3% growth from 2000 to 2001.

Jewish religious movements

Rabbinic Judaism

Rabbinic Judaism (or in some Christian traditions, Rabbinism) (Hebrew: "Yahadut Rabanit" - יהדות רבנית) has been the mainstream form of Judaism since the 6th century CE, after the codification of the Talmud. It is characterised by the belief that the Written Torah (Law) cannot be correctly interpreted without reference to the Oral Torah and by the voluminous literature specifying what behavior is sanctioned by the law (called halakha, "the way").

The Jewish Enlightenment of the late 18th century resulted in the division of Ashkenazi (Western) Jewry into religious movements or denominations, especially in North America and Anglophone countries. The main denominations today outside Israel (where the situation is rather different) are Orthodox, Conservative, and Reform.
  • Orthodox Judaism holds that both the Written and Oral Torah were divinely revealed to Moses, and that the laws within it are binding and unchanging. Orthodox Jews generally consider commentaries on the Shulchan Aruch (a condensed codification of halakha that largely favored Sephardic traditions) to be the definitive codification of Jewish law. Orthodoxy places a high importance on Maimonides' 13 principles as a definition of Jewish faith.
  • Conservative Judaism, known as Masorti outside the United States and Canada, is characterized by a commitment to traditional Jewish laws and customs, including observance of Shabbat and kashrut, a deliberately non-fundamentalist teaching of Jewish principles of faith, a positive attitude toward modern culture, and an acceptance of both traditional rabbinic and modern scholarship when considering Jewish religious texts. Conservative Judaism teaches that Jewish law is not static, but has always developed in response to changing conditions. It holds that the Torah is a divine document written by prophets inspired by God and reflecting his will, but rejects the Orthodox position that it was dictated by God to Moses.[75][76] Conservative Judaism holds that the Oral Law is divine and normative, but holds that both the Written and Oral Law may be interpreted by the rabbis to reflect modern sensibilities and suit modern conditions.
  • Reform Judaism, called Liberal or Progressive Judaism in many countries, defines Judaism as a religion rather than as a race or culture, rejects most of the ritual and ceremonial laws of the Torah while observing moral laws, and emphasizes the ethical call of the Prophets. Reform Judaism has developed an egalitarian prayer service in the vernacular (along with Hebrew in many cases) and emphasizes personal connection to Jewish tradition.
A Reform synagogue with mixed seating and equal participation of men and women
  • Reconstructionist Judaism, like Reform Judaism, does not hold that Jewish law, as such, requires observance, but unlike Reform, Reconstructionist thought emphasizes the role of the community in deciding what observances to follow.
  • Jewish Renewal is a recent North American movement which focuses on spirituality and social justice, but does not address issues of Jewish law. Men and women participate equally in prayer.
  • Humanistic Judaism is a small non-theistic movement centered in North America and Israel that emphasizes Jewish culture and history as the sources of Jewish identity.

Jewish movements in Israel

Most Jewish Israelis classify themselves as "secular" (hiloni), "traditional" (masorti), "religious" (dati) or Haredi. The term "secular" is more popular as a self-description among Israeli families of western (European) origin, whose Jewish identity may be a very powerful force in their lives, but who see it as largely independent of traditional religious belief and practice. This portion of the population largely ignores organized religious life, be it of the official Israeli rabbinate (Orthodox) or of the liberal movements common to diaspora Judaism (Reform, Conservative).
The term "traditional" (masorti) is most common as a self-description among Israeli families of "eastern" origin (i.e., the Middle East, Central Asia, and North Africa). This term, as commonly used, has nothing to do with the official Masorti (Conservative) movement. There is a great deal of ambiguity in the ways "secular" and "traditional" are used in Israel: they often overlap, and they cover an extremely wide range in terms of ideology and religious observance. The term "Orthodox" is not popular in Israeli discourse, although the percentage of Jews who come under that category is far greater than in the diaspora. What would be called "Orthodox" in the diaspora includes what is commonly called dati (religious) or haredi (ultra-Orthodox) in Israel. The former term includes what is called "Religious Zionism" or the "National Religious" community, as well as what has become known over the past decade or so as haredi-leumi (nationalist haredi), or "Hardal", which combines a largely haredi lifestyle with nationalist ideology. (Some people, in Yiddish, also refer to observant Orthodox Jews as frum, as opposed to frei (more liberal Jews)).

Haredi applies to a populace that can be roughly divided into three separate groups along both ethnic and ideological lines: (1) "Lithuanian" (non-hasidic) haredim of Ashkenazic origin; (2) Hasidic haredim of Ashkenazic origin; and (3) Sephardic haredim.

Alternative Judaism

Karaite Judaism defines itself as the remnants of the non-Rabbinic Jewish sects of the Second Temple period, such as the Sadducees. The Karaites ("Scripturalists") accept only the Hebrew Bible and what they view as the Peshat ("simple" meaning); they do not accept non-biblical writings as authoritative.
Some European Karaites do not see themselves as part of the Jewish community at all, although most do. The Samaritans, a very small community located entirely around Mount Gerizim in the Nablus/Shechem region of the West Bank and in Holon, near Tel Aviv in Israel, regard themselves as the descendants of the Israelites of the Iron Age kingdom of Israel. Their religious practices are those of Judaism, but they regard only the written Torah as authoritative scripture (with a special regard also for the Samaritan Book of Joshua).

Jewish observances

Jewish ethics

Jewish ethics may be guided by halakhic traditions, by other moral principles, or by central Jewish virtues. Jewish ethical practice is typically understood to be marked by values such as justice, truth, peace, loving-kindness (chesed), compassion, humility, and self-respect. Specific Jewish ethical practices include practices of charity (tzedakah) and refraining from negative speech (lashon hara). Proper ethical practices regarding sexuality and many other issues are subjects of dispute among Jews.

Prayers

A Yemenite Jew at morning prayers, wearing a kippah skullcap, prayer shawl and tefillin

Traditionally, Jews recite prayers three times daily, Shacharit, Mincha, and Ma'ariv with a fourth prayer, Mussaf added on Shabbat and holidays. At the heart of each service is the Amidah or Shemoneh Esrei. Another key prayer in many services is the declaration of faith, the Shema Yisrael (or Shema). The Shema is the recitation of a verse from the Torah (Deuteronomy 6:4): Shema Yisrael Adonai Eloheinu Adonai Echad—"Hear, O Israel! The Lord is our God! The Lord is One!"

Most of the prayers in a traditional Jewish service can be recited in solitary prayer, although communal prayer is preferred. Communal prayer requires a quorum of ten adult Jews, called a minyan. In nearly all Orthodox and a few Conservative circles, only male Jews are counted toward a minyan; most Conservative Jews and members of other Jewish denominations count female Jews as well.

In addition to prayer services, observant traditional Jews recite prayers and benedictions throughout the day when performing various acts. Prayers are recited upon waking up in the morning, before eating or drinking different foods, after eating a meal, and so on.

The approach to prayer varies among the Jewish denominations. Differences can include the texts of prayers, the frequency of prayer, the number of prayers recited at various religious events, the use of musical instruments and choral music, and whether prayers are recited in the traditional liturgical languages or the vernacular. In general, Orthodox and Conservative congregations adhere most closely to tradition, and Reform and Reconstructionist synagogues are more likely to incorporate translations and contemporary writings in their services. Also, in most Conservative synagogues, and all Reform and Reconstructionist congregations, women participate in prayer services on an equal basis with men, including roles traditionally filled only by men, such as reading from the Torah. In addition, many Reform temples use musical accompaniment such as organs and mixed choirs.

Religious clothing

A kippah (Hebrew: כִּפָּה, plural kippot; Yiddish: יאַרמלקע, yarmulke) is a slightly rounded brimless skullcap worn by many Jews while praying, eating, reciting blessings, or studying Jewish religious texts, and at all times by some Jewish men. In Orthodox communities, only men wear kippot; in non-Orthodox communities, some women also wear kippot. Kippot range in size from a small round beanie that covers only the back of the head, to a large, snug cap that covers the whole crown. Tzitzit (Hebrew: צִיציִת) (Ashkenazi pronunciation: tzitzis) are special knotted "fringes" or "tassels" found on the four corners of the tallit (Hebrew: טַלִּית) (Ashkenazi pronunciation: tallis), or prayer shawl. The tallit is worn by Jewish men and some Jewish women during the prayer service. Customs vary regarding when a Jew begins wearing a tallit. In the Sephardi community, boys wear a tallit from bar mitzvah age. In some Ashkenazi communities it is customary to wear one only after marriage. A tallit katan (small tallit) is a fringed garment worn under the clothing throughout the day. In some Orthodox circles, the fringes are allowed to hang freely outside the clothing.

Tefillin (Hebrew: תְפִלִּין), known in English as phylacteries (from the Greek word φυλακτήριον, meaning safeguard or amulet), are two square leather boxes containing biblical verses, attached to the forehead and wound around the left arm by leather straps. They are worn during weekday morning prayer by observant Jewish men and some Jewish women.[77]

A kittel (Yiddish: קיטל), a white knee-length overgarment, is worn by prayer leaders and some observant traditional Jews on the High Holidays. It is traditional for the head of the household to wear a kittel at the Passover seder in some communities, and some grooms wear one under the wedding canopy. Jewish males are buried in a tallit and sometimes also a kittel which are part of the tachrichim (burial garments).

Jewish holidays

Jewish holidays are special days in the Jewish calendar, which celebrate moments in Jewish history, as well as central themes in the relationship between God and the world, such as creation, revelation, and redemption.

Shabbat

Two braided Shabbat challahs placed under an embroidered challah cover at the start of the Shabbat meal

Shabbat, the weekly day of rest lasting from shortly before sundown on Friday night to nightfall Saturday night, commemorates God's day of rest after six days of creation.[78] It plays a pivotal role in Jewish practice and is governed by a large corpus of religious law. At sundown on Friday, the woman of the house welcomes the Shabbat by lighting two or more candles and reciting a blessing. The evening meal begins with the Kiddush, a blessing recited aloud over a cup of wine, and the Mohtzi, a blessing recited over the bread. It is customary to have challah, two braided loaves of bread, on the table. During Shabbat Jews are forbidden to engage in any activity that falls under 39 categories of melakhah, translated literally as "work". In fact the activities banned on the Sabbath are not "work" in the usual sense: They include such actions as lighting a fire, writing, using money and carrying in the public domain. The prohibition of lighting a fire has been extended in the modern era to driving a car, which involves burning fuel, and using electricity.

Three pilgrimage festivals

Some sukkot in Jerusalem

Jewish holy days (chaggim), celebrate landmark events in Jewish history, such as the Exodus from Egypt and the giving of the Torah, and sometimes mark the change of seasons and transitions in the agricultural cycle. The three major festivals, Sukkot, Passover and Shavuot, are called "regalim" (derived from the Hebrew word "regel", or foot). On the three regalim, it was customary for the
Israelites to make pilgrimages to Jerusalem to offer sacrifices in the Temple.
  • Passover (Pesach) is a week-long holiday beginning on the evening of the 14th day of Nisan (the first month in the Hebrew calendar), that commemorates the Exodus from Egypt. Outside Israel, Passover is celebrated for eight days. In ancient times, it coincided with the barley harvest. It is the only holiday that centers on home-service, the Seder. Leavened products (chametz) are removed from the house prior to the holiday, and are not consumed throughout the week. Homes are thoroughly cleaned to ensure no bread or bread by-products remain, and a symbolic burning of the last vestiges of chametz is conducted on the morning of the Seder. Matzo is eaten instead of bread.
  • Shavuot ("Pentecost" or "Feast of Weeks") celebrates the revelation of the Torah to the Israelites on Mount Sinai. Also known as the Festival of Bikurim, or first fruits, it coincided in biblical times with the wheat harvest. Shavuot customs include all-night study marathons known as Tikkun Leil Shavuot, eating dairy foods (cheesecake and blintzes are special favorites), reading the Book of Ruth, decorating homes and synagogues with greenery, and wearing white clothing, symbolizing purity.
  • Sukkot ("Tabernacles" or "The Festival of Booths") commemorates the Israelites' forty years of wandering through the desert on their way to the Promised Land. It is celebrated through the construction of temporary booths called sukkot (sing. sukkah) that represent the temporary shelters of the Israelites during their wandering. It coincides with the fruit harvest, and marks the end of the agricultural cycle. Jews around the world eat in sukkot for seven days and nights. Sukkot concludes with Shemini Atzeret, where Jews begin to pray for rain and Simchat Torah, "Rejoicing of the Torah", a holiday which marks reaching the end of the Torah reading cycle and beginning all over again. The occasion is celebrated with singing and dancing with the Torah scrolls. Shemini Atzeret and Simchat Torah are technically considered to be a separate holiday and not a part of Sukkot.

High Holy Days

Jews praying in a synagogue on Yom Kippur, from an 1878 painting by Maurycy Gottlieb

The High Holidays (Yamim Noraim or "Days of Awe") revolve around judgment and forgiveness.
  • Rosh Hashanah, (also Yom Ha-Zikkaron or "Day of Remembrance", and Yom Teruah, or "Day of the Sounding of the Shofar"). Rosh Hashanah is the Jewish New Year (literally, "head of the year"), although it falls on the first day of the seventh month of the Hebrew calendar, Tishri. Rosh Hashanah marks the beginning of the 10-day period of atonement leading up to Yom Kippur, during which Jews are commanded to search their souls and make amends for sins committed, intentionally or not, throughout the year. Holiday customs include blowing the shofar, or ram's horn, in the synagogue, eating apples and honey, and saying blessings over a variety of symbolic foods, such as pomegranates.
  • Yom Kippur, ("Day of Atonement") is the holiest day of the Jewish year. It is a day of communal fasting and praying for forgiveness for one's sins. Observant Jews spend the entire day in the synagogue, sometimes with a short break in the afternoon, reciting prayers from a special holiday prayerbook called a "Machzor". Many non-religious Jews make a point of attending synagogue services and fasting on Yom Kippur. On the eve of Yom Kippur, before candles are lit, a prefast meal, the "seuda mafseket", is eaten. Synagogue services on the eve of Yom Kippur begin with the Kol Nidre prayer. It is customary to wear white on Yom Kippur, especially for Kol Nidre, and leather shoes are not worn. The following day, prayers are held from morning to evening. The final prayer service, called "Ne'ilah", ends with a long blast of the shofar.

Purim

Purim street scene in Jerusalem

Purim (Hebrew: About this sound פורים (help·info) Pûrîm "lots") is a joyous Jewish holiday that commemorates the deliverance of the Persian Jews from the plot of the evil Haman, who sought to exterminate them, as recorded in the biblical Book of Esther. It is characterized by public recitation of the Book of Esther, mutual gifts of food and drink, charity to the poor, and a celebratory meal (Esther 9:22). Other customs include drinking wine, eating special pastries called hamantashen, dressing up in masks and costumes, and organizing carnivals and parties.

Purim is celebrated annually on the 14th of the Hebrew month of Adar, which occurs in February or March of the Gregorian calendar.

Hanukkah

Hanukkah (Hebrew: חֲנֻכָּה‎, "dedication") also known as the Festival of Lights, is an eight-day Jewish holiday that starts on the 25th day of Kislev (Hebrew calendar). The festival is observed in Jewish homes by the kindling of lights on each of the festival's eight nights, one on the first night, two on the second night and so on.
The holiday was called Hanukkah (meaning "dedication") because it marks the re-dedication of the Temple after its desecration by Antiochus IV Epiphanes. Spiritually, Hanukkah commemorates the "Miracle of the Oil". According to the Talmud, at the re-dedication of the Temple in Jerusalem following the victory of the Maccabees over the Seleucid Empire, there was only enough consecrated oil to fuel the eternal flame in the Temple for one day. Miraculously, the oil burned for eight days - which was the length of time it took to press, prepare and consecrate new oil.

Hanukkah is not mentioned in the Bible and was never considered a major holiday in Judaism, but it has become much more visible and widely celebrated in modern times, mainly because it falls around the same time as Christmas and has national Jewish overtones that have been emphasized since the establishment of the State of Israel.

Other days

Tisha B'Av (Hebrew: תשעה באב‎ or ט׳ באב, "the Ninth of Av") is a day of mourning and fasting commemorating the destruction of the First and Second Temples, and in later times, the expulsion of the Jews from Spain.
The modern holidays of Yom Ha-shoah (Holocaust Remembrance Day) and Yom Ha'atzmaut (Israeli Independence Day) commemorate the horrors of the Holocaust and the achievement of Israel independence, respectively.

Torah readings

The core of festival and Shabbat prayer services is the public reading of the Torah, along with connected readings from the other books of the Tanakh, called Haftarah. Over the course of a year, the whole Torah is read, with the cycle starting over in the autumn, on Simchat Torah.

Synagogues and religious buildings

Interior of the Esnoga synagogue in Amsterdam

Synagogues are Jewish houses of prayer and study. They usually contain separate rooms for prayer (the main sanctuary), smaller rooms for study, and often an area for community or educational use. There is no set blueprint for synagogues and the architectural shapes and interior designs of synagogues vary greatly. The Reform movement mostly refer to their synagogues as temples. Some traditional features of a synagogue are:
  • The ark (called aron ha-kodesh by Ashkenazim and hekhal by Sephardim) where the Torah scrolls are kept (the ark is often closed with an ornate curtain (parochet) outside or inside the ark doors);
  • The elevated reader's platform (called bimah by Ashkenazim and tebah by Sephardim), where the Torah is read (and services are conducted in Sephardi synagogues);
  • The eternal light (ner tamid), a continually lit lamp or lantern used as a reminder of the constantly lit menorah of the Temple in Jerusalem
  • The pulpit, or amud, a lectern facing the Ark where the hazzan or prayer leader stands while praying.
In addition to synagogues, other buildings of significance in Judaism include yeshivas, or institutions of Jewish learning, and mikvahs, which are ritual baths.

Dietary laws: kashrut

The Jewish dietary laws are known as kashrut. Food prepared in accordance with them is termed kosher, and food that is not kosher is also known as treifah or treif. People who observe these laws are colloquially said to be "keeping kosher".[79]
Many of the laws apply to animal-based foods. For example, in order to be considered kosher, mammals must have split hooves and chew their cud. The pig is arguably the most well-known example of a non-kosher animal.[80] Although it has split hooves, it does not chew its cud.[81] For seafood to be kosher, the animal must have fins and scales. Certain types of seafood, such as shellfish, crustaceans, and eels, are therefore considered non-kosher. Concerning birds, a list of non-kosher species is given in the Torah. The exact translations of many of the species have not survived, and some non-kosher birds' identities are no longer certain. However, traditions exist about the kashrut status of a few birds. For example, both chickens and turkeys are permitted in most communities. Other types of animals, such as amphibians, reptiles, and most insects, are prohibited altogether.[79]

In addition to the requirement that the species be considered kosher, meat and poultry (but not fish) must come from a healthy animal slaughtered in a process known as shechitah. Without the proper slaughtering practices even an otherwise kosher animal will be rendered treif. The slaughtering process is intended to be quick and relatively painless to the animal. Forbidden parts of animals include the blood, some fats, and the area in and around the sciatic nerve.[79]

Jewish law also forbids the consumption of meat and dairy products together. The waiting period between eating meat and eating dairy varies by the order in which they are consumed and by community, and can extend for up to six hours. Based on the Biblical injunction against cooking a kid in its mother's milk, this rule is mostly derived from the Oral Torah, the Talmud and Rabbinic law.[79] Chicken and other kosher birds are considered the same as meat under the laws of kashrut, but the prohibition is Rabbinic, not Biblical.[82]

The use of dishes, serving utensils, and ovens may make food treif that would otherwise be kosher. Utensils that have been used to prepare non-kosher food, or dishes that have held meat and are now used for dairy products, render the food treif under certain conditions.[79]

Furthermore, all Orthodox and some Conservative authorities forbid the consumption of processed grape products made by non-Jews, due to ancient pagan practices of using wine in rituals.[79] Some Conservative authorities permit wine and grape juice made without rabbinic supervision.[83]

The Torah does not give specific reasons for most of the laws of kashrut.[79] However, a number of explanations have been offered, including maintaining ritual purity, teaching impulse control, encouraging obedience to God, improving health, reducing cruelty to animals and preserving the distinctness of the Jewish community.[84] The various categories of dietary laws may have developed for different reasons, and some may exist for multiple reasons. For example, people are forbidden from consuming the blood of birds and mammals because, according to the Torah, this is where animal souls are contained.[85] In contrast, the Torah forbids Israelites from eating non-kosher species because "they are unclean".[86] The Kabbalah describes sparks of holiness that are released by the act of eating kosher foods, but are too tightly bound in non-kosher foods to be released by eating.[87]

Survival concerns supersede all the laws of kashrut, as they do for most halakhot.[88][89]

Laws of ritual purity

A silver matchbox holder for ritual use on Shabbat with inscription in Hebrew

The Tanakh describes circumstances in which a person who is tahor or ritually pure may become tamei or ritually impure. Some of these circumstances are contact with human corpses or graves, seminal flux, vaginal flux, menstruation, and contact with people who have become impure from any of these.[90][91] In Rabbinic Judaism, Kohanim, members of the hereditary caste that served as priests in the time of the Temple, are mostly restricted from entering grave sites and touching dead bodies.[92] During the Temple period, such priests (Kohanim) were required to eat their bread offering (Terumah) in a state of ritual purity, which laws eventually led to more rigid laws being enacted, such as hand-washing which became a requisite of all Jews before consuming ordinary bread.

Family purity

An important subcategory of the ritual purity laws relates to the segregation of menstruating women. These laws are also known as niddah, literally "separation", or family purity. Vital aspects of halakha for traditionally observant Jews, they are not usually followed by Jews in liberal denominations.[93] Especially in Orthodox Judaism, the Biblical laws are augmented by Rabbinical injunctions. For example, the Torah mandates that a woman in her normal menstrual period must abstain from sexual intercourse for seven days. A woman whose menstruation is prolonged must continue to abstain for seven more days after bleeding has stopped.[90] The Rabbis conflated ordinary niddah with this extended menstrual period, known in the Torah as zavah, and mandated that a woman may not have sexual intercourse with her husband from the time she begins her menstrual flow until seven days after it ends. In addition, Rabbinical law forbids the husband from touching or sharing a bed with his wife during this period. Afterwards, purification can occur in a ritual bath called a mikveh.[93]

Traditional Ethiopian Jews keep menstruating women in separate huts and, similar to Karaite practice, do not allow menstruating women into their temples because of a temple's special sanctity. Emigration to Israel and the influence of other Jewish denominations have led to Ethiopian Jews adopting more normative Jewish practices.[94][95]

Life-cycle events

Life-cycle events, or rites of passage, occur throughout a Jew's life that serve to strengthen Jewish identity and bind him/her to the entire community.
  • Brit milah – Welcoming male babies into the covenant through the rite of circumcision on their eighth day of life. The baby boy is also given his Hebrew name in the ceremony. A naming ceremony intended as a parallel ritual for girls, named zeved habat or brit bat, enjoys limited popularity.
  • Bar mitzvah and Bat mitzvah – This passage from childhood to adulthood takes place when a female Jew is twelve and a male Jew is thirteen years old among Orthodox and some Conservative congregations. In the Reform movement, both girls and boys have their bat/bar mitzvah at age thirteen. This is often commemorated by having the new adults, male only in the Orthodox tradition, lead the congregation in prayer and publicly read a "portion" of the Torah.
  • Marriage – Marriage is an extremely important lifecycle event. A wedding takes place under a chupah, or wedding canopy, which symbolizes a happy house. At the end of the ceremony, the groom breaks a glass with his foot, symbolizing the continuous mourning for the destruction of the Temple, and the scattering of the Jewish people.
  • Death and Mourning – Judaism has a multi-staged mourning practice. The first stage is called the shiva (literally "seven", observed for one week) during which it is traditional to sit at home and be comforted by friends and family, the second is the shloshim (observed for one month) and for those who have lost one of their parents, there is a third stage, avelut yud bet chodesh, which is observed for eleven months.

Community leadership

Classical priesthood

Jewish students with their teacher in Samarkand, Uzbekistan c. 1910.

The role of the priesthood in Judaism has significantly diminished since the destruction of the Second Temple in 70 CE, when priests attended to the Temple and sacrifices. The priesthood is an inherited position, and although priests no longer have any but ceremonial duties, they are still honored in many Jewish communities. Many Orthodox Jewish communities believe that they will be needed again for a future Third Temple and need to remain in readiness for future duty.
  • Kohen (priest) - patrilineal descendant of Aaron, brother of Moses. In the Temple, the kohanim were charged with performing the sacrifices. Today, a Kohen is the first one called up at the reading of the Torah, performs the Priestly Blessing, as well as complying with other unique laws and ceremonies, including the ceremony of redemption of the first-born.
  • Levi (Levite) - Patrilineal descendant of Levi the son of Jacob. In the Temple in Jerusalem, the levites sang Psalms, performed construction, maintenance, janitorial, and guard duties, assisted the priests, and sometimes interpreted the law and Temple ritual to the public. Today, a Levite is called up second to the reading of the Torah.

Prayer leaders

From the time of the Mishnah and Talmud to the present, Judaism has required specialists or authorities for the practice of very few rituals or ceremonies. A Jew can fulfill most requirements for prayer by himself. Some activities—reading the Torah and haftarah (a supplementary portion from the Prophets or Writings), the prayer for mourners, the blessings for bridegroom and bride, the complete grace after meals—require a minyan, the presence of ten Jews.

The most common professional clergy in a synagogue are:
  • Rabbi of a congregation - Jewish scholar who is charged with answering the legal questions of a congregation. This role requires ordination by the congregation's preferred authority (i.e. from a respected Orthodox rabbi or, if the congregation is Conservative or Reform, from academic seminaries). A congregation does not necessarily require a rabbi. Some congregations have a rabbi but also allow members of the congregation to act as shatz or baal kriyah (see below).
    • Hassidic Rebbe - rabbi who is the head of a Hasidic dynasty.
  • Hazzan (note: the "h" denotes voiceless pharyngeal fricative) (cantor) - a trained vocalist who acts as shatz. Chosen for a good voice, knowledge of traditional tunes, understanding of the meaning of the prayers and sincerity in reciting them. A congregation does not need to have a dedicated hazzan.
Jewish prayer services do involve two specified roles, which are sometimes, but not always, filled by a rabbi and/or hazzan in many congregations. In other congregations these roles are filled on an ad-hoc basis by members of the congregation who lead portions of services on a rotating basis:
  • Shaliach tzibur or Shatz (leader—literally "agent" or "representative"—of the congregation) leads those assembled in prayer, and sometimes prays on behalf of the community. When a shatz recites a prayer on behalf of the congregation, he is not acting as an intermediary but rather as a facilitator. The entire congregation participates in the recital of such prayers by saying amen at their conclusion; it is with this act that the shatz's prayer becomes the prayer of the congregation. Any adult capable of reciting the prayers clearly may act as shatz. In Orthodox congregations and some Conservative congregations, only men can be prayer leaders, but all Progressive communities now allow women to serve in this function.
  • The Baal kriyah or baal koreh (master of the reading) reads the weekly Torah portion. The requirements for being the baal kriyah are the same as those for the shatz. These roles are not mutually exclusive. The same person is often qualified to fill more than one role, and often does. Often there are several people capable of filling these roles and different services (or parts of services) will be led by each.
Many congregations, especially larger ones, also rely on a:
  • Gabbai (sexton) - Calls people up to the Torah, appoints the shatz for each prayer session if there is no standard shatz, and makes certain that the synagogue is kept clean and supplied.
The three preceding positions are usually voluntary and considered an honor. Since the Enlightenment large synagogues have often adopted the practice of hiring rabbis and hazzans to act as shatz and baal kriyah, and this is still typically the case in many Conservative and Reform congregations. However, in most Orthodox synagogues these positions are filled by laypeople on a rotating or ad-hoc basis. Although most congregations hire one or more Rabbis, the use of a professional hazzan is generally declining in American congregations, and the use of professionals for other offices is rarer still.

Specialized religious roles

  • Dayan (judge) - An ordained rabbi with special legal training who belongs to a beth din (rabbinical court). In Israel, religious courts handle marriage and divorce cases, conversion and financial disputes in the Jewish community.
  • Mohel (circumciser) - An expert in the laws of circumcision who has received training from a previously qualified mohel and performs the brit milah (circumcision).
  • Shochet (ritual slaughterer) - In order for meat to be kosher, it must be slaughtered by a shochet who is an expert in the laws of kashrut and has been trained by another shochet.
  • Sofer (scribe) - Torah scrolls, tefillin (phylacteries), mezuzot (scrolls put on doorposts), and gittin (bills of divorce) must be written by a sofer who is an expert in Hebrew calligraphy and has undergone rigorous training in the laws of writing sacred texts.
  • Rosh yeshiva - A Torah scholar who runs a yeshiva.
  • Mashgiach of a yeshiva - Depending on which yeshiva, might either be the person responsible for ensuring attendance and proper conduct, or even supervise the emotional and spiritual welfare of the students and give lectures on mussar (Jewish ethics).
  • Mashgiach - Supervises manufacturers of kosher food, importers, caterers and restaurants to ensure that the food is kosher. Must be an expert in the laws of kashrut and trained by a rabbi, if not a rabbi himself.

History

Origins

Scenes from the Book of Esther decorate the Dura-Europos synagogue dating from 244 CE

At its core, the Tanakh is an account of the Israelites' relationship with God from their earliest history until the building of the Second Temple (c. 535 BCE). Abraham is hailed as the first Hebrew and the father of the Jewish people. As a reward for his act of faith in one God, he was promised that Isaac, his second son, would inherit the Land of Israel (then called Canaan). Later, the descendants of Isaac's son Jacob were enslaved in Egypt, and God commanded Moses to lead the Exodus from Egypt. At Mount Sinai they received the Torah - the five books of Moses. These books, together with Nevi'im and Ketuvim are known as Torah Shebikhtav as opposed to the Oral Torah, which refers to the Mishna and the Talmud. Eventually, God led them to the land of Israel where the tabernacle was planted in the city of Shiloh for over 300 years to rally the nation against attacking enemies. As time went on, the spiritual level of the nation declined to the point that God allowed the Philistines to capture the tabernacle. The people of Israel then told Samuel the prophet that they needed to be governed by a permanent king, and Samuel appointed Saul to be their King. When the people pressured Saul into going against a command conveyed to him by Samuel, God told Samuel to appoint David in his stead.
The Western Wall in Jerusalem is a remnant of the wall encircling the Second Temple. The Temple Mount is the holiest site in Judaism.

Once King David was established, he told the prophet Nathan that he would like to build a permanent temple, and as a reward for his actions, God promised David that he would allow his son, Solomon, to build the first permanent temple and the throne would never depart from his children.

Rabbinic tradition holds that the details and interpretation of the law, which are called the Oral Torah or oral law, were originally an unwritten tradition based upon what God told Moses on Mount Sinai. However, as the persecutions of the Jews increased and the details were in danger of being forgotten, these oral laws were recorded by Rabbi Judah haNasi (Judah the Prince) in the Mishnah, redacted circa 200 CE. The Talmud was a compilation of both the Mishnah and the Gemara, rabbinic commentaries redacted over the next three centuries. The Gemara originated in two major centers of Jewish scholarship, Palestine and Babylonia. Correspondingly, two bodies of analysis developed, and two works of Talmud were created. The older compilation is called the Jerusalem Talmud. It was compiled sometime during the 4th century in Israel. The Babylonian Talmud was compiled from discussions in the houses of study by the scholars Ravina I, Ravina II, and Rav Ashi by 500 CE, although it continued to be edited later.

Some critical scholars oppose the view that the sacred texts, including the Hebrew Bible, were divinely inspired. Many of these scholars accept the general principles of the documentary hypothesis and suggest that the Torah consists of inconsistent texts edited together in a way that calls attention to divergent accounts.[96][97][98] Many suggest that during the First Temple period, the people of Israel believed that each nation had its own god, but that their god was superior to other gods.[99][100] Some suggest that strict monotheism developed during the Babylonian Exile, perhaps in reaction to Zoroastrian dualism.[101] In this view, it was only by the Hellenic period that most Jews came to believe that their god was the only god, and that the notion of a clearly bounded Jewish nation identical with the Jewish religion formed.[102]

John Day argues that the origins of biblical Yahweh, El, Asherah, and Ba'al, may be rooted in earlier Canaanite religion, which was centered on a pantheon of gods much like the Greek Pantheon.[103]

Antiquity

The United Monarchy was established under Saul and continued under King David and Solomon with its capital in Jerusalem. After Solomon's reign the nation split into two kingdoms, the Kingdom of Israel (in the north) and the Kingdom of Judah (in the south). The Kingdom of Israel was conquered by the Assyrian ruler Sargon II in the late 8th century BCE with many people from the capital Samaria being taken captive to Media and the Khabur River valley. The Kingdom of Judah continued as an independent state until it was conquered by a Babylonian army in the early 6th century BCE, destroying the First Temple that was at the center of ancient Jewish worship. The Judean elite were exiled to Babylonia and this is regarded as the first Jewish Diaspora. Later many of them returned to their homeland after the subsequent conquest of Babylonia by the Persians seventy years later, a period known as the Babylonian Captivity. A new Second Temple was constructed, and old religious practices were resumed.
During the early years of the Second Temple, the highest religious authority was a council known as the Great Assembly, led by Ezra of the Book of Ezra. Among other accomplishments of the Great Assembly, the last books of the Bible were written at this time and the canon sealed.

Hellenistic Judaism spread to Ptolemaic Egypt from the 3rd century BCE. After the Great Revolt (66–73 CE), the Romans destroyed the Temple. Hadrian built a pagan idol on the Temple grounds and prohibited circumcision; these acts of ethnocide provoked the Bar Kokhba revolt 132–136 CE after which the Romans banned the study of the Torah and the celebration of Jewish holidays, and forcibly removed virtually all Jews from Judea. In 200 CE, however, Jews were granted Roman citizenship and Judaism was recognized as a religio licita ("legitimate religion"), until the rise of Gnosticism and Early Christianity in the fourth century.

Following the destruction of Jerusalem and the expulsion of the Jews, Jewish worship stopped being centrally organized around the Temple, prayer took the place of sacrifice, and worship was rebuilt around the community (represented by a minimum of ten adult men) and the establishment of the authority of rabbis who acted as teachers and leaders of individual communities (see Jewish diaspora).

Historical Jewish groupings (to 1700)

The Torah Ark of the Beth Jakov synagogue in Macedonia

Around the 1st century CE there were several small Jewish sects: the Pharisees, Sadducees, Zealots, Essenes, and Christians. After the destruction of the Second Temple in 70 CE, these sects vanished. Christianity survived, but by breaking with Judaism and becoming a separate religion; the Pharisees survived but in the form of Rabbinic Judaism (today, known simply as "Judaism"). The Sadducees rejected the divine inspiration of the Prophets and the Writings, relying only on the Torah as divinely inspired. Consequently, a number of other core tenets of the Pharisees' belief system (which became the basis for modern Judaism), were also dismissed by the Sadducees. (The Samaritans practiced a similar religion, which is traditionally considered separate from Judaism.)

Like the Sadducees who relied only on the Torah, some Jews in the 8th and 9th centuries rejected the authority and divine inspiration of the oral law as recorded in the Mishnah (and developed by later rabbis in the two Talmuds), relying instead only upon the Tanakh. These included the Isunians, the Yudganites, the Malikites, and others. They soon developed oral traditions of their own, which differed from the rabbinic traditions, and eventually formed the Karaite sect. Karaites exist in small numbers today, mostly living in Israel. Rabbinical and Karaite Jews each hold that the others are Jews, but that the other faith is erroneous.

Over a long time, Jews formed distinct ethnic groups in several different geographic areas — amongst others, the Ashkenazi Jews (of central and Eastern Europe), the Sephardi Jews (of Spain, Portugal, and North Africa), the Beta Israel of Ethiopia, and the Yemenite Jews from the southern tip of the Arabian Peninsula. Many of these groups have developed differences in their prayers, traditions and accepted canons; however these distinctions are mainly the result of their being formed at some cultural distance from normative (rabbinic) Judaism, rather than based on any doctrinal dispute.

Persecutions

Antisemitism arose during the Middle Ages, in the form of persecutions, pogroms, forced conversion, expulsions, social restrictions and ghettoization.
This was different in quality to any repressions of Jews in ancient times. Ancient repression was politically motivated and Jews were treated the same way as any other ethnic group would have been. With the rise of the Churches, attacks on Jews became motivated instead by theological considerations specifically deriving from Christian views about Jews and Judaism.[104]

Hasidism

Hasidic Judaism was founded by Yisroel ben Eliezer (1700–1760), also known as the Ba'al Shem Tov (or Besht). It originated in a time of persecution of the Jewish people, when European Jews had turned inward to Talmud study; many felt that most expressions of Jewish life had become too "academic", and that they no longer had any emphasis on spirituality or joy. His disciples attracted many followers; they themselves established numerous Hasidic sects across Europe. Hasidic Judaism eventually became the way of life for many Jews in Europe. Waves of Jewish immigration in the 1880s carried it to the United States. The movement itself claims to be nothing new, but a refreshment of original Judaism. Or as some have put it: "they merely re-emphasized that which the generations had lost".[105] Nevertheless, early on there was a serious schism between Hasidic and non-Hasidic Jews. European Jews who rejected the Hasidic movement were dubbed by the Hasidim as Misnagdim, (lit. "opponents"). Some of the reasons for the rejection of Hasidic Judaism were the overwhelming exuberance of Hasidic worship, its untraditional ascriptions of infallibility and alleged miracle-working to their leaders, and the concern that it might become a messianic sect. Since then differences between the Hasidim and their opponents have slowly diminished and both groups are now considered part of Haredi Judaism.

The Enlightenment and new religious movements

In the late 18th century CE, Europe was swept by a group of intellectual, social and political movements known as the Enlightenment. The Enlightenment led to reductions in the European laws that prohibited Jews to interact with the wider secular world, thus allowing Jews access to secular education and experience. A parallel Jewish movement, Haskalah or the "Jewish Enlightenment", began, especially in Central Europe and Western Europe, in response to both the Enlightenment and these new freedoms. It placed an emphasis on integration with secular society and a pursuit of non-religious knowledge through reason. With the promise of political emancipation many Jews saw no reason to continue to observe Jewish law and increasing numbers of Jews assimilated into Christian Europe. Modern religious movements of Judaism all formed in reaction to this trend.
In Central Europe, followed by Great Britain and the United States, Reform Judaism and Liberal Judaism developed, relaxing legal obligations (especially those that limited Jewish relations with non-Jews), emulating Protestant decorum in prayer, and emphasizing the ethical values of Judaism's Prophetic tradition. Modern Orthodox Judaism developed in reaction to Reform Judaism, by leaders who argued that Jews could participate in public life as citizens equal to Christians, while maintaining the observance of Jewish law. Meanwhile, in the United States, wealthy Reform Jews helped European scholars, who were Orthodox in practice but critical (and skeptical) in their study of the Bible and Talmud, to establish a seminary to train rabbis for immigrants from Eastern Europe. These left-wing Orthodox rabbis were joined by right-wing Reform rabbis who felt that Jewish law should not be entirely abandoned, to form the Conservative movement. Orthodox Jews who opposed the Haskalah formed Haredi Orthodox Judaism. After massive movements of Jews following The Holocaust and the creation of the state of Israel, these movements have competed for followers from among traditional Jews in or from other countries.

Spectrum of observance

Judaism is practised in all parts of the world, for example in a synagogue in downtown Mumbai.

Countries such as the United States, Israel, Canada, United Kingdom, Argentina and South Africa contain large Jewish populations. Jewish religious practice varies widely through all levels of observance. According to the 2001 edition of the National Jewish Population Survey, in the United States' Jewish community—the world's second largest—4.3 million Jews out of 5.1 million had some sort of connection to the religion. Of that population of connected Jews, 80% participated in some sort of Jewish religious observance, but only 48% belonged to a synagogue, and fewer than 16% attend regularly.[106]

Birth rates for American Jews have dropped from 2.0 to 1.7.[107] (Replacement rate is 2.1.) Intermarriage rates range from 40-50% in the US, and only about a third of children of intermarried couples are raised as Jews. Due to intermarriage and low birth rates, the Jewish population in the US shrank from 5.5 million in 1990 to 5.1 million in 2001. This is indicative of the general population trends among the Jewish community in the Diaspora, but a focus on total population obscures growth trends in some denominations and communities, such as Haredi Judaism. The Baal teshuva movement is a movement of Jews who have "returned" to religion or become more observant.

Judaism and other religions

Christianity and Judaism

The most profound difference between traditional Jewish belief and that of Christianity is in its belief in the expected Messiah. Traditional Jewish belief holds that the Messiah of Israel is yet to come, while Christians view the Messiah in the personage of Jesus. The disparity between these two views has often given rise to tension and, occasionally, has spilled over into violence.

One of the basic positions held by Orthodox Jews regarding the Messiah is that he will come from King David’s lineage and he will bring peace into the world.[108]

Historians and theologians regularly review the changing relationship between some Christian groups and the Jewish people; the article on Christian–Jewish reconciliation studies one recent issue.

Islam and Judaism

The relationship between Islam and Judaism is special and close. Both religions claim to arise from the patriarch Abraham, and are therefore considered Abrahamic religions. As fellow monotheists, Muslims view Jews as "people of the book", a term that Jews have subsequently adopted as a way of describing their own connection to the Torah and other holy texts.[109] In turn, many Jews maintain that Muslims adhere to the Seven Laws of Noah. Thus, Judaism views Muslims as righteous people of God.[110] Jews have interacted with Muslims since the 7th century, when Islam originated and spread in the Arabian peninsula, and many aspects of Islam's core values, structure, jurisprudence and practice are based on Judaism.[111][112] Muslim culture and philosophy have heavily influenced practitioners of Judaism in the Islamic world.[113]
In premodern Muslim countries, Jews rarely faced martyrdom, exile or forcible conversion, and were mostly free in their choice of residence and profession.[114] Indeed, the years 712 to 1066 CE under the Ummayad and the Abbasid rulers have been called the Golden age of Jewish culture in Spain. Non-Muslim monotheists living in these countries, including Jews, were known as dhimmis. Dhimmis were allowed to practice their religion and to administer their internal affairs, but they were subject to certain restrictions that were not imposed on Muslims.[115] For example, they had to pay the jizya, a per capita tax imposed on free adult non-Muslim males,[115] and they were also forbidden to bear arms or testify in court cases involving Muslims.[116] Many of the laws regarding dhimmis were highly symbolic. For example, dhimmis in some countries were required to wear distinctive clothing, a practice not found in either the Qur'an or hadiths but invented in early medieval Baghdad and inconsistently enforced.[117] Jews in Muslim countries were not entirely free from persecution—for example, many were killed, exiled or forcibly converted in the 12th century, in Persia and by the rulers of the Almohad dynasty in North Africa and Al-Andalus.[118] At times, Jews were also restricted in their choice of residence—in Morocco, Jews were confined to walled quarters (mellahs) beginning in the 15th century and increasingly since the early 19th century.[119]

In the late 20th century, Jews were expelled from nearly all the Arab countries.[120][121][122] Most have chosen to live in Israel. Today, antisemitic themes have become commonplace in the propaganda of Arab Islamic movements such as Hizbullah and Hamas, in the pronouncements of various agencies of the Islamic Republic of Iran, and even in the newspapers and other publications of Refah Partisi.[123]

Syncretic movements incorporating Judaism

There are some movements that combine elements of Judaism with those of other religions. The most well-known of these is Messianic Judaism, which arose in the 1960s.[124][125][126][127] It blends evangelical Christian theology with elements of Jewish terminology and ritual.[127][128][129][130][131]
The movement states that Jesus is the Jewish Messiah, and generally that he is part of the Trinity,[132][133] and salvation is only achieved through acceptance of Jesus as one's savior.[134] Some members of the movement are ethnically Jewish, and some of them argue that Messianic Judaism is a sect of Judaism.[135] Jewish organizations and religious movements reject this, stating that Messianic Judaism is a Christian sect.[136]

Other examples of syncretism include Semitic neopaganism, a loosely organized set of Jews who incorporate pagan or Wiccan beliefs with some Jewish religious practices; Jewish Buddhists, another loosely organized group that incorporates elements of Asian spirituality in their faith; and some Renewal Jews who borrow freely and openly from Buddhism, Sufism, Native American religion, and other faiths.

The Kabbalah Centre, which employs teachers from multiple religions, is a New Age movement that claims to popularize the kabbalah, part of the Jewish esoteric tradition.
at

Moore's law

Moore's law

From Wikipedia, the free encyclopedia

Plot of CPU transistor counts against dates of introduction. Note the logarithmic vertical scale; the line corresponds to exponential growth with transistor count doubling every two years.
An Osborne Executive portable computer, from 1982 with a Zilog Z80 4MHz CPU, and a 2007 Apple iPhone with a 412MHz ARM11 CPU. The Executive weighs 100 times as much, has nearly 500 times as much volume, cost approximately 10 times as much (adjusted for inflation), and has about 1/100th the clock frequency of the smartphone.

Moore's law is the observation that, over the history of computing hardware, the number of transistors in a dense integrated circuit doubles approximately every two years. The law is named after Gordon E. Moore, co-founder of Intel Corporation, who described the trend in his 1965 paper.[1][2][3] His prediction has proven to be accurate, in part because the law is now used in the semiconductor industry to guide long-term planning and to set targets for research and development.[4] The capabilities of many digital electronic devices are strongly linked to Moore's law: quality-adjusted microprocessor prices,[5] memory capacity, sensors and even the number and size of pixels in digital cameras.[6] All of these are improving at roughly exponential rates as well. This exponential improvement has dramatically enhanced the impact of digital electronics in nearly every segment of the world economy.[7] Moore's law describes a driving force of technological and social change, productivity and economic growth in the late 20th and early 21st centuries.[8][9][10][11]

The period is often quoted as 18 months because of Intel executive David House, who predicted that chip performance would double every 18 months (being a combination of the effect of more transistors and their being faster).[12]

Although this trend has continued for more than half a century, Moore's law should be considered an observation or conjecture and not a physical or natural law. Sources in 2005 expected it to continue until at least 2015 or 2020.[note 1][14] However, the 2010 update to the International Technology Roadmap for Semiconductors predicted that growth will slow at the end of 2013,[15] when transistor counts and densities are to double only every three years.

History

Gordon Moore in 2004

The term "Moore's law" was coined around 1970 by the Caltech professor, VLSI pioneer, and entrepreneur Carver Mead in reference to a statement by Gordon E. Moore.[2][16] Predictions of similar increases in computer power had existed years prior. Moore may have heard Douglas Engelbart, a co-inventor of today's mechanical computer mouse, discuss the projected downscaling of integrated circuit size in a 1960 lecture.[17] A New York Times article published August 31, 2009, credits Engelbart as having made the prediction in 1959.[18]

Moore's original statement that transistor counts had doubled every year can be found in his publication "Cramming more components onto integrated circuits", Electronics Magazine 19 April 1965. The paper noted that the number of components in integrated circuits had doubled every year from the invention of the integrated circuit in 1958 until 1965[19] and then concluded:
The complexity for minimum component costs has increased at a rate of roughly a factor of two per year. Certainly over the short term this rate can be expected to continue, if not to increase. Over the longer term, the rate of increase is a bit more uncertain, although there is no reason to believe it will not remain nearly constant for at least 10 years. That means by 1975, the number of components per integrated circuit for minimum cost will be 65,000. I believe that such a large circuit can be built on a single wafer.[1]
Moore slightly altered the formulation of the law over time, in retrospect bolstering the perceived accuracy of his law.[20] Most notably, in 1975, Moore altered his projection to a doubling every two years.[21][22] Despite popular misconception, he is adamant that he did not predict a doubling "every 18 months." However, David House, an Intel colleague, had factored in the increasing performance of transistors to conclude that integrated circuits would double in performance every 18 months.[note 2]

In April 2005, Intel offered US$10,000 to purchase a copy of the original Electronics Magazine issue in which Moore's article appeared.[24] An engineer living in the United Kingdom was the first to find a copy and offer it to Intel.[25]

Other formulations and similar laws

Several measures of digital technology are improving at exponential rates related to Moore's law, including the size, cost, density and speed of components. Moore himself wrote only about the density of components, "a component being a transistor, resistor, diode or capacitor,"[26] at minimum cost.

Transistors per integrated circuit. The most popular formulation is of the doubling of the number of transistors on integrated circuits every two years. At the end of the 1970s, Moore's law became known as the limit for the number of transistors on the most complex chips. The graph at the top shows this trend holds true today.

Density at minimum cost per transistor. This is the formulation given in Moore's 1965 paper.[1] It is not just about the density of transistors that can be achieved, but about the density of transistors at which the cost per transistor is the lowest.[27] As more transistors are put on a chip, the cost to make each transistor decreases, but the chance that the chip will not work due to a defect increases. In 1965, Moore examined the density of transistors at which cost is minimized, and observed that, as transistors were made smaller through advances in photolithography, this number would increase at "a rate of roughly a factor of two per year".[1]

Dennard scaling. This suggests that power requirements are proportional to area (both voltage and current being proportional to length) for transistors. Combined with Moore's law, performance per watt would grow at roughly the same rate as transistor density, doubling every 1–2 years. According to Dennard scaling transistor dimensions are scaled by 30% (0.7x) every technology generation, thus reducing their area by 50%. This reduces the delay by 30% (0.7x) and therefore increases operating frequency by about 40% (1.4x). Finally, to keep electric field constant, voltage is reduced by 30%, reducing energy by 65% and power (at 1.4x frequency) by 50%.[note 3] Therefore, in every technology generation transistor density doubles, circuit becomes 40% faster, while power consumption (with twice the number of transistors) stays the same.[28]

The exponential processor transistor growth predicted by Moore does not always translate into exponentially greater practical CPU performance. Since around 2005–2007, Dennard scaling appears to have broken down, so even though Moore's law continued for several years after that, it has not yielded dividends in improved performance.[29][30][31] The primary reason cited for the breakdown is that at small sizes, current leakage poses greater challenges, and also causes the chip to heat up, which creates a threat of thermal runaway and therefore further increases energy costs.[29][30][31] The breakdown of Dennard scaling prompted a switch among some chip manufacturers to a greater focus on multicore processors, but the gains offered by switching to more cores are lower than the gains that would be achieved had Dennard scaling continued.[32][33] In another departure from Dennard scaling, Intel microprocessors adopted a non-planar tri-gate FinFET at 22 nm in 2012 which is faster and consumes less power than a conventional planar transistor.[34]

Quality adjusted price of IT equipment. The price of Information Technology (IT), computers and peripheral equipment, adjusted for quality and inflation, declined 16% per year on average over the five decades from 1959 to 2009.[35] However, the pace accelerated to 23% per year in 1995-1999 triggered by[11] faster IT innovation, and later slowed to 2% per year in 2010-2013.[35][36] The rate of quality-adjusted microprocessor price improvement likewise varies, and is not linear on a log scale. Microprocessor price improvement accelerated during the late 1990s, reaching 60% per year (halving every nine months) versus the typical 30% improvement rate (halving every two years) during the years earlier and later.[37][38]

The number of transistors per chip cannot explain quality-adjusted microprocessor prices fully.[37][39][40] Moore's 1995 paper does not limit Moore's law to strict linearity or to transistor count, “The definition of 'Moore's Law' has come to refer to almost anything related to the semiconductor industry that when plotted on semi-log paper approximates a straight line. I hesitate to review its origins and by doing so restrict its definition.”[26]

Moore (2003) credits chemical mechanical planarization (chip smoothing) with increasing the connectivity of microprocessors from two or three metal layers in the early 1990s to seven in 2003.[41] This has leveled off at 9-11 layers since 2007.[42][43] Connectivity improves performance, and relieves network congestion. Just as additional floors may not enlarge a building's footprint, nor is connectivity tallied in transistor count. Microprocessors rely more on communications (interconnect) than do DRAM chips, which have three or four metal layers.[44][45][46] Microprocessor prices in the late 1990s improved faster than DRAM prices.[37]

Hard disk drive areal density. A similar law (sometimes called Kryder's law) has held for hard disk drive areal density.[47] The rate of progress in disk storage over the past decades has sped up more than once, corresponding to the utilization of error correcting codes, the magnetoresistive effect and the giant magnetoresistive effect. The outlook for the rate of progress slowed in recent years, because of noise related to smaller grain size of the disk media, thermal stability and writability using available magnetic fields.[48]

Network capacity. According to Gerry/Gerald Butters,[49][50] the former head of Lucent's Optical Networking Group at Bell Labs, there is another version, called Butters' Law of Photonics,[51] a formulation which deliberately parallels Moore's law. Butter's law[52] says that the amount of data coming out of an optical fiber is doubling every nine months. Thus, the cost of transmitting a bit over an optical network decreases by half every nine months. The availability of wavelength-division multiplexing (sometimes called WDM) increased the capacity that could be placed on a single fiber by as much as a factor of 100. Optical networking and dense wavelength-division multiplexing (DWDM) is rapidly bringing down the cost of networking, and further progress seems assured. As a result, the wholesale price of data traffic collapsed in the dot-com bubble. Nielsen's Law says that the bandwidth available to users increases by 50% annually.[53]

Pixels per dollar. Similarly, Barry Hendy of Kodak Australia has plotted pixels per dollar as a basic measure of value for a digital camera, demonstrating the historical linearity (on a log scale) of this market and the opportunity to predict the future trend of digital camera price, LCD and LED screens and resolution.[54][55][56]

The great Moore's law compensator (TGMLC), generally referred to as bloat, and also known as Wirth's law, is the principle that successive generations of computer software acquire enough bloat to offset the performance gains predicted by Moore's law. In a 2008 article in InfoWorld, Randall C. Kennedy,[57] formerly of Intel, introduces this term using successive versions of Microsoft Office between the year 2000 and 2007 as his premise. Despite the gains in computational performance during this time period according to Moore's law, Office 2007 performed the same task at half the speed on a prototypical year 2007 computer as compared to Office 2000 on a year 2000 computer.

Library expansion was calculated in 1945 by Fremont Rider to double in capacity every 16 years, if sufficient space were made available.[58] He advocated replacing bulky, decaying printed works with miniaturized microform analog photographs, which could be duplicated on-demand for library patrons or other institutions. He did not foresee the digital technology that would follow decades later to replace analog microform with digital imaging, storage, and transmission mediums. Automated, potentially lossless digital technologies allowed vast increases in the rapidity of information growth in an era that is now sometimes called an Information Age.

The Carlson Curve is a term coined by The Economist [59] to describe the biotechnological equivalent of Moore's law, and is named after author Rob Carlson.[60] Carlson accurately predicted that the doubling time of DNA sequencing technologies (measured by cost and performance) would be at least as fast as Moore's law.[61] Carlson Curves illustrate the rapid (in some cases hyperexponential) decreases in cost, and increases in performance, of a variety of technologies, including DNA sequencing, DNA synthesis and a range of physical and computational tools used in protein expression and in determining protein structures.

As a target for industry and a self-fulfilling prophecy

Although Moore's law was initially made in the form of an observation and forecast, the more widely it became accepted, the more it served as a goal for an entire industry. This drove both marketing and engineering departments of semiconductor manufacturers to focus enormous energy aiming for the specified increase in processing power that it was presumed one or more of their competitors would soon actually attain. In this regard, it can be viewed as a self-fulfilling prophecy.[4][62]

Moore's second law

As the cost of computer power to the consumer falls, the cost for producers to fulfill Moore's law follows an opposite trend: R&D, manufacturing, and test costs have increased steadily with each new generation of chips. Rising manufacturing costs are an important consideration for the sustaining of Moore's law.[63] This had led to the formulation of Moore's second law, also called Rock's law, which is that the capital cost of a semiconductor fab also increases exponentially over time.[64][65]

Major enabling factors and future trends

Numerous innovations by a large number of scientists and engineers have helped significantly to sustain Moore's law since the beginning of the integrated circuit (IC) era. Whereas assembling a detailed list of such significant contributions would be as desirable as it would be difficult, below just a few innovations are listed as examples of breakthroughs that have played a critical role in the advancement of integrated circuit technology by more than seven orders of magnitude in less than five decades:
  • The foremost contribution, which is the raison d’etre for Moore's law, is the invention of the integrated circuit itself, credited contemporaneously to Jack Kilby at Texas Instruments[66] and Robert Noyce at Fairchild Semiconductor.[67]
  • The invention of the complementary metal–oxide–semiconductor (CMOS) process by Frank Wanlass in 1963.[68] A number of advances in CMOS technology by many workers in the semiconductor field since the work of Wanlass have enabled the extremely dense and high-performance ICs that the industry makes today.
  • The invention of the dynamic random access memory (DRAM) technology by Robert Dennard at I.B.M. in 1967.[69] that made it possible to fabricate single-transistor memory cells, and the invention of flash memory by Fujio Masuoka at Toshiba in the 1980s,[70][71][72] leading to low-cost, high-capacity memory in diverse electronic products.
  • The invention of chemically amplified photoresist by C. Grant Willson, Hiroshi Ito and J.M.J. Fréchet at IBM c.1980,[73][74][75] that was 10-100 times more sensitive to ultraviolet light.[76] IBM introduced chemically amplified photoresist for DRAM production in the mid-1980s.[77][78]
  • The invention of deep UV excimer laser photolithography by Kanti Jain[79] at IBM c.1980,[80][81][82] that has enabled the smallest features in ICs to shrink from 800 nanometers in 1990 to as low as 22 nanometers in 2012.[83] This built on the invention of the excimer laser in 1970[84] by Nikolai Basov, V. A. Danilychev and Yu. M. Popov, at the Lebedev Physical Institute. From a broader scientific perspective, the invention of excimer laser lithography has been highlighted as one of the major milestones in the 50-year history of the laser.[85][86]
  • The interconnect innovations of the late 1990s. IBM developed CMP or chemical mechanical planarization c.1980, based on the centuries-old polishing process for making telescope lenses.[87] CMP smooths the chip surface. Intel used chemical-mechanical polishing to enable additional layers of metal wires in 1990; higher transistor density (tighter spacing) via trench isolation, local polysilicon (wires connecting nearby transistors) and improved wafer yield (all in 1995).[88][41] Higher yield, the fraction of working chips on a wafer, reduces manufacturing cost. IBM with assistance from Motorola used CMP for lower electrical resistance copper interconnect instead of aluminum in 1997.[89]
Computer industry technology roadmaps predict (as of 2001) that Moore's law will continue for several generations of semiconductor chips. Depending on the doubling time used in the calculations, this could mean up to a hundredfold increase in transistor count per chip within a decade. The semiconductor industry technology roadmap uses a three-year doubling time for microprocessors, leading to a tenfold increase in the next decade.[90] Intel was reported in 2005 as stating that the downsizing of silicon chips with good economics can continue during the next decade,[note 1] and in 2008 as predicting the trend through 2029.[91]

Some of the new directions in research that may allow Moore's law to continue are:
  • In April 2008, researchers at HP Labs announced the creation of a working memristor, a fourth basic passive circuit element whose existence had previously only been theorized. The memristor's unique properties permit the creation of smaller and better-performing electronic devices.[94]
  • In February 2010, Researchers at the Tyndall National Institute in Cork, Ireland announced a breakthrough in transistors with the design and fabrication of the world's first junctionless transistor. The research led by Professor Jean-Pierre Colinge was published in Nature Nanotechnology and describes a control gate around a silicon nanowire that can tighten around the wire to the point of closing down the passage of electrons without the use of junctions or doping. The researchers claim that the new junctionless transistors can be produced at 10-nanometer scale using existing fabrication techniques.[95]
  • In April 2011, a research team at the University of Pittsburgh announced the development of a single-electron transistor 1.5 nanometers in diameter made out of oxide based materials. According to the researchers, three "wires" converge on a central "island" which can house one or two electrons. Electrons tunnel from one wire to another through the island. Conditions on the third wire result in distinct conductive properties including the ability of the transistor to act as a solid state memory.[96]
  • In February 2012, a research team at the University of New South Wales announced the development of the first working transistor consisting of a single atom placed precisely in a silicon crystal (not just picked from a large sample of random transistors).[97] Moore's law predicted this milestone to be reached in the lab by 2020.
  • In April 2014, bioengineers at Stanford University developed a new circuit board modeled on the human brain. 16 custom designed "Neurocore" chips simulate 1 million neurons and billions of synaptic connections. This Neurogrid is claimed to be 9,000 times faster and more energy efficient than a typical PC. The cost of the prototype was $40,000; however with current technology a similar Neurogrid could be made for $400.[98]
  • The advancement of nanotechnology could spur the creation of microscopic computers and restore Moore's Law to its original rate of growth.[99][100][101]

The trend of scaling for NAND flash memory allows doubling of components manufactured in the same wafer area in less than 18 months.

Ultimate limits of the law

Atomistic simulation result for formation of inversion channel (electron density) and attainment of threshold voltage (IV) in a nanowire MOSFET. Note that the threshold voltage for this device lies around 0.45 V. Nanowire MOSFETs lie towards the end of the ITRS roadmap for scaling devices below 10 nm gate lengths.[90]

On 13 April 2005, Gordon Moore stated in an interview that the law cannot be sustained indefinitely: "It can't continue forever. The nature of exponentials is that you push them out and eventually disaster happens". He also noted that transistors would eventually reach the limits of miniaturization at atomic levels:
In terms of size [of transistors] you can see that we're approaching the size of atoms which is a fundamental barrier, but it'll be two or three generations before we get that far—but that's as far out as we've ever been able to see. We have another 10 to 20 years before we reach a fundamental limit. By then they'll be able to make bigger chips and have transistor budgets in the billions.[102]
In January 1995, the Digital Alpha 21164 microprocessor had 9.3 million transistors. This 64-bit processor was a technological spearhead at the time, even if the circuit's market share remained average. Six years later, a state of the art microprocessor contained more than 40 million transistors. It is theorised that with further miniaturisation, by 2015 these processors should contain more than 15 billion transistors, and by 2020 will be in molecular scale production, where each molecule can be individually positioned.[103]

In 2003, Intel predicted the end would come between 2013 and 2018 with 16 nanometer manufacturing processes and 5 nanometer gates, due to quantum tunnelling, although others suggested chips could just get bigger, or become layered.[104] In 2008 it was noted that for the last 30 years it has been predicted that Moore's law would last at least another decade.[91]

Some see the limits of the law as being in the distant future. Lawrence Krauss and Glenn D. Starkman announced an ultimate limit of around 600 years in their paper,[105] based on rigorous estimation of total information-processing capacity of any system in the Universe, which is limited by the Bekenstein bound. On the other hand, based on first principles, there are predictions that Moore's law will collapse in the next few decades [20–40 years]".[106][107]

One could also limit the theoretical performance of a rather practical "ultimate laptop" with a mass of one kilogram and a volume of one litre. This is done by considering the speed of light, the quantum scale, the gravitational constant and the Boltzmann constant, giving a performance of 5.4258 ⋅ 1050 logical operations per second on approximately 1031 bits.[108]

Then again, the law has often met obstacles that first appeared insurmountable but were indeed surmounted before long. In that sense, Moore says he now sees his law as more beautiful than he had realized: "Moore's law is a violation of Murphy's law. Everything gets better and better."[109]

Futurists and Moore's law

Kurzweil's extension of Moore's law from integrated circuits to earlier transistors, vacuum tubes, relays and electromechanical computers.
If the current trend continues to 2020, the number of transistors would reach 32 billion.[clarification needed]

Futurists such as Ray Kurzweil, Bruce Sterling, and Vernor Vinge believe that the exponential improvement described by Moore's law will ultimately lead to a technological singularity: a period where progress in technology occurs almost instantly.[110]

Although Kurzweil agrees that by 2019 the current strategy of ever-finer photolithography will have run its course, he speculates that this does not mean the end of Moore's law:
Moore's law of Integrated Circuits was not the first, but the fifth paradigm to forecast accelerating price-performance ratios. Computing devices have been consistently multiplying in power (per unit of time) from the mechanical calculating devices used in the 1890 U.S. Census, to [Newman] relay-based "[Heath] Robinson" machine that cracked the Lorenz cipher, to the CBS vacuum tube computer that predicted the election of Eisenhower, to the transistor-based machines used in the first space launches, to the integrated-circuit-based personal computer.[111]
Kurzweil speculates that it is likely that some new type of technology (e.g. optical, quantum computers, DNA computing) will replace current integrated-circuit technology, and that Moore's Law will hold true long after 2020.[111]
Seth Lloyd shows how the potential computing capacity of a kilogram of matter equals pi times energy divided by Planck's constant. Since the energy is such a large number and Planck's constant is so small, this equation generates an extremely large number: about 5.0 * 1050 operations per second.[110]
He believes that the exponential growth of Moore's law will continue beyond the use of integrated circuits into technologies that will lead to the technological singularity. The Law of Accelerating Returns described by Ray Kurzweil has in many ways altered the public's perception of Moore's law. It is a common (but mistaken) belief that Moore's law makes predictions regarding all forms of technology, when it was originally intended to apply only to semiconductor circuits. Many futurists still use the term Moore's law in this broader sense to describe ideas like those put forth by Kurzweil. Kurzweil has hypothesised that Moore's law will apply – at least by inference – to any problem that can be attacked by digital computers as is in its essence also a digital problem. Therefore, because of the digital coding of DNA, progress in genetics may also advance at a Moore's law rate. Moore himself, who never intended his law to be interpreted so broadly, has quipped:
Moore's law has been the name given to everything that changes exponentially. I say, if Gore invented the Internet, I invented the exponential.[112][note 4]

Consequences and limitations

Technological change is a combination of more and of better technology. A 2011 study in the journal Science showed that the peak of the rate of change of the world's capacity to compute information was in the year 1998, when the world's technological capacity to compute information on general-purpose computers grew at 88% per year.[114] Since then, technological change has clearly slowed. In recent times, every new year allowed mankind to carry out roughly 60% of the computations that could have possibly been executed by all existing general-purpose computers before that year.[114] This is still exponential, but shows the varying nature of technological change.[115]

The primary driving force of economic growth is the growth of productivity,[116] and Moore's law factors into productivity. Moore (1995) expected that “the rate of technological progress is going to be controlled from financial realities.”[26] However, the reverse could and did occur around the late-1990s, with economists reporting that "Productivity growth is the key economic indicator of innovation."[11] An acceleration in the rate of semiconductor progress contributed to a surge in US productivity growth[117][118][119] which reached 3.4% per year in 1997-2004, outpacing the 1.6% per year during both 1972-1996 and 2005-2013.[120] As economist Richard G. Anderson notes, “Numerous studies have traced the cause of the productivity acceleration to technological innovations in the production of semiconductors that sharply reduced the prices of such components and of the products that contain them (as well as expanding the capabilities of such products).”[121]
Intel transistor gate length trend. Transistor scaling has slowed down significantly at advanced (smaller) nodes.

While physical limits to transistor scaling such as source-to-drain leakage, limited gate metals, and limited options for channel material have been reached, new avenues for continued scaling are open. The most promising of these approaches rely on using the spin state of electron spintronics, tunnel junctions, and advanced confinement of channel materials via nano-wire geometry. A comprehensive list of available device choices shows[122] that a wide range of device options is open for continuing Moore's law into the next few decades. Spin-based logic and memory options are actively being developed in industrial labs[123] as well as academic labs.[124]

Another source of improved performance is in microarchitecture techniques exploiting the growth of available transistor count. Out-of-order execution and on-chip caching and prefetching reduce the memory latency bottleneck at the expense of using more transistors and increasing the processor complexity. These increases are empirically described by Pollack's Rule which states that performance increases due to microarchitecture techniques are square root of the number of transistors or the area of a processor.

For years, processor makers delivered increases in clock rates and instruction-level parallelism, so that single-threaded code executed faster on newer processors with no modification.[125] Now, to manage CPU power dissipation, processor makers favor multi-core chip designs, and software has to be written in a multi-threaded manner to take full advantage of the hardware. Many multi-threaded development paradigms introduce overhead, and will not see a linear increase in speed vs number of processors. This is particularly true while accessing shared or dependent resources, due to lock contention. This effect becomes more noticeable as the number of processors increases. There are cases where a roughly 45% increase in processor transistors have translated to roughly 10–20% increase in processing power.[126]

On the other hand, processor manufactures are taking advantage of the 'extra space' that the transistor shrinkage provides to add specialized processing units to deal with features such as graphics, video and cryptography. For one example, Intel's Parallel JavaScript extension not only adds support for multiple cores, but also for the other non-general processing features of their chips, as part of the migration in client side scripting towards HTML5.[127]

A negative implication of Moore's law is obsolescence, that is, as technologies continue to rapidly "improve", these improvements can be significant enough to rapidly render predecessor technologies obsolete. In situations in which security and survivability of hardware or data are paramount, or in which resources are limited, rapid obsolescence can pose obstacles to smooth or continued operations.[128] Because of the toxic materials used in the production of modern computers, obsolescence if not properly managed can lead to harmful environmental impacts.[129]

Moore's law has significantly impacted the performance of other technologies: Michael S. Malone wrote of a Moore's War following the apparent success of shock and awe in the early days of the Iraq War. Progress in the development of guided weapons depends on electronic technology.[130] Improvements in circuit density and low-power operation associated with Moore's law have also contributed to the development of Star Trek-like technologies including mobile phones[131] and replicator-like 3D printing.[132]
at

Alternate mechanism of species formation picks up support, thanks to a South American ant

Alternate mechanism of species formation picks up support, thanks to a South American ant

Date:
August 21, 2014
Source:
University of Rochester, link http://www.sciencedaily.com/releases/2014/08/140821124835.htm
Summary:
A newly discovered species of ant supports a controversial theory of species formation. The ant, only found in a single patch of eucalyptus trees on the São Paulo State University campus in Brazil, branched off from its original species while living in the same colony, something thought rare in current models of evolutionary development.

A queen ant of the parasitic species Mycocepurus castrator (left) and a queen ant of the host species Mycocepurus goeldii queen (right).
 Credit: Christian Rabeling/University of Rochester



A newly-discovered species of ant supports a controversial theory of species formation. The ant, only found in a single patch of eucalyptus trees on the São Paulo State University campus in Brazil, branched off from its original species while living in the same colony, something thought rare in current models of evolutionary development.

"Most new species come about in geographic isolation," said Christian Rabeling, assistant professor of biology at the University of Rochester. "We now have evidence that speciation can take place within a single colony."

The findings by Rabeling and the research team were published today in the journal Current Biology.

In discovering the parasitic Mycocepurus castrator, Rabeling and his colleagues uncovered an example of a still-controversial theory known as sympatric speciation, which occurs when a new species develops while sharing the same geographic area with its parent species, yet reproducing on its own."While sympatric speciation is more difficult to prove," said Rabeling, "we believe we are in the process of actually documenting a particular kind of evolution-in-progress."

New species are formed when its members are no longer able to reproduce with members of the parent species. The commonly-accepted mechanism is called allopatric speciation, in which geographic barriers -- such as mountains -- separate members of a group, causing them to evolve independently.

"Since Darwin's Origin of Species, evolutionary biologists have long debated whether two species can evolve from a common ancestor without being geographically isolated from each other," said Ted Schultz, curator of ants at the Smithsonian's National Museum of Natural History and co-author of the study. "With this study, we offer a compelling case for sympatric evolution that will open new conversations in the debate about speciation in these ants, social insects and evolutionary biology more generally."

M. castrator is not simply another ant in the colony; it's a parasite that lives with -- and off of -- its host, Mycocepurus goeldii. The host is a fungus-growing ant that cultivates fungus for its nutritional value, both for itself and, indirectly, for its parasite, which does not participate in the work of growing the fungus garden. That led the researchers to study the genetic relationships of all fungus-growing ants in South America, including all five known and six newly discovered species of the genus Mycocepurus, to determine whether the parasite did evolve from its presumed host. They found that the parasitic ants were, indeed, genetically very close to M. goeldii, but not to the other ant species.

They also determined that the parasitic ants were no longer reproductively compatible with the host ants -- making them a unique species -- and had stopped reproducing with their host a mere 37,000 years ago -- a very short period on the evolutionary scale.

A big clue for the research team was found by comparing the ants' genes, both in the cell's nucleus as well as in the mitochondria -- the energy-producing structures in the cells. Genes are made of units called nucleotides, and Rabeling found that the sequencing of those nucleotides in the mitochondria is beginning to look different from what is found in the host ants, but that the genes in the nucleus still have traces of the relationship between host and parasite, leading him to conclude that M. castrator has begun to evolve away from its host.

Rabeling explained that just comparing some nuclear and mitochondrial genes may not be enough to demonstrate that the parasitic ants are a completely new species. "We are now sequencing the entire mitochondrial and nuclear genomes of these parasitic ants and their host in an effort to confirm speciation and the underlying genetic mechanism."

The parasitic ants need to exercise discretion because taking advantage of the host species is considered taboo in ant society. Offending ants have been known to be killed by worker mobs. As a result, the parasitic queen of the new species has evolved into a smaller size, making them difficult to distinguish from a host worker.

Host queens and males reproduce in an aerial ceremony, in the wet tropics only during a particular season when it begins to rain. Rabeling found that the parasitic queens and males, needing to be more discreet about their reproductive activities, diverge from the host's mating pattern. By needing to hide their parasitic identity, M. castrator males and females lost their special adaptations that allowed them to reproduce in flight, and mate inside the host nest, making it impossible for them to sexually interact with their host species.

The research team included Ted Schultz of the Smithsonian Institution's National Museum of Natural History, Naomi Pierce of Harvard University, and Maurício Bacci, Jr of the Center for the Study of Social Insects (São State University, Rio Claro, Brazil).
Story Source:

The above story is based on materials provided by University of Rochester. Note: Materials may be edited for content and length.
Journal Reference:
  1. Christian Rabeling, Ted R. Schultz, Naomi E. Pierce, Maurício Bacci. A Social Parasite Evolved Reproductive Isolation from Its Fungus-Growing Ant Host in Sympatry. Current Biology, 2014; DOI: 10.1016/j.cub.2014.07.048
at
Subscribe to: Posts (Atom)

Lie group

From Wikipedia, the free encyclopedia https://en.wikipedia.org/wiki/Lie_group In mathematics , a Lie gro...

  • Islamic State and the Levant
    From Wikipedia, the free encyclopedia Islamic State of Iraq and the Levant الدولة الإسلامية في العراق والشام   ( ...
  • Heart Sutra
    From Wikipedia, the free encyclopedia A reproduction of the palm -leaf manuscript in Siddham script ...
  • Slum
    From Wikipedia, the free encyclopedia ...