The concept of "world religion" is historically based on a subjective perception of temporal or theological importance, usually from a Western, "Christian" (or at least "Abrahamic") perspective.citation needed
Early Christian scholars, the earliest known classifiers of major religions, recognized two "proper" religions, Christianity and Judaism, besides heretical deviations from Christianity, and idolatrous relapse or paganism. Islamic theology recognizes Christians and Jews as "People of the Book" rather than idolaters, however, Christians are criticized for believing in Christ as God incarnate, rather than considering Christ as one prophet and/or messenger along with others (especially Muhammad in particular). The Christian view long classified Islam's rejection of Christ's divinity as one heresy among others. The concept of the Trinity is often seen as a fundamental conflict between Islam and some interpretations of Christianity to this day.citation needed
Attempts to identify and classify additional religions expanded during the Enlightenment however, and by the 19th century Western scholars considered the five "world religions" to be Judaism, Christianity, Islam, Hinduism and Buddhism. These remain the classic "world religions."citation needed
Modern classifications
Modern classifications typically list major religious groups by number of adherents, not by historical or theological notability. Most dramatically, this affects Judaism, which holds the position of "world religion" as the foundational tradition of the "Abrahamic" group, but which in terms of adherents ranks below 0.25% of world population, behind Sikhism.citation needed
The remaining four classic world religions, Christianity, Islam, Hinduism and Buddhism, are the largest contemporary religions by far. They each have more than 300 million adherents, more than ten times the number of the next largest organized religion (Sikhism, ca. 19 million per the Christian Science Monitor source cited below).
A person is typically considered an adherent or follower of a particular religion if the person would self-identify the religion as the primary characterization of their religious perspective[1]. Similarly, a religion is typically considered to fall within a larger religious category (e.g., Protestantism falling within Christianity) if the followers of the religion self-identify that classification as appropriate.
An example of a modern listing of "world religions" is that of the Ontario Consultants on Religious Tolerance, listing twelve "long established, major world religions, each with over three million followers", alphabetically:
The Adherents.com list of "twelve classical world religions" is nearly identical, but replaces Vodou with Zoroastrianism.
The "World's Major Religions" list published in the New York Public Library Student's Desk Reference[2] omits Vodou and Zoroastrianism, as well as Jainism and Sikhism, but lists the Eastern Orthodox Church, Protestantism and Roman Catholicism as separate religions.
The Christian Science Monitor, in a 1998 article "Top 10 Organized Religions in the World," provides a listing of the largest "organized religions" [3]:
Abrahamic religions are by far the largest group, and these consist primarily of Christianity, Islam and Judaism (sometimes Bahá'í Faith is also included). They are named for their common patriarch Abraham, and are unified by their strict monotheism. Today, around 3.4 billion people are followers of Abrahamic religions and are spread widely around the world apart from the regions around southeast Asia and China.
Demographic distribution of the major super-groupings mentioned is shown in the table below (with number of followers estimates from Adherents.com for groups having such figures available there):
One way to define a major religion is by the number of current adherents. The population numbers by religion are computed by a combination of census reports and population surveys (in countries where religion data is not collected in census, for example USA or France), but results can vary widely depending on the way questions are phrased, the definitions of religion used and the bias of the agencies or organizations conducting the survey. Informal or unorganized religions are especially difficult to count.
There is no consensus among researchers as to the best methodology for determining the religiosity profile of the world's population. A number of fundamental aspects are unresolved:
Whether to count "historically predominant religious culture[s]"[5]
Whether to count only those who actively "practice" a particular religion[6]
Whether to count based on a concept of "adherence"[7]
Whether to count only those who expressly self-identify with a particular denomination[8]
Whether to count only adults, or to include children as well.
Whether to rely only on official government-provided statistics[9]
Whether to use multiple sources and ranges or single "best source(s)"
Largest religions or belief systems by number of adherents
This reliability is also not established. relies largely or entirely upon a single source.
Please help improve this article by introducing appropriate citations of additional sources. (November 2007)
This listing[a] includes both organized religions, which have unified belief codes and religious hierarchies, and informal religions, such as Chinese folk religions. For completeness, it also contains a category for the non-religious, although their views would not ordinarily be considered a religion.
Category includes a wide range of beliefs, without specifically adhering to a religion or sometimes specifically against dogmatic religions. The category includes humanism, deism, pantheism, rationalism, freethought, agnosticism and atheism. Broadly labeled humanism, this group of non religious people are third largest in the world. For more information, see the Adherents.com discussion of this category and the note below. [c]
Not a single organized religion, includes elements of Taoism, Confucianism, Buddhism and traditional nonscriptural religious observance (also called "Chinese traditional religion").[b]
Not a single organized religion, includes a wide range of traditional or tribal religions, including animism, shamanism and paganism. Since African traditional and diasporic religions are counted separately in this list, most of the people counted in this group are in Asia.
Not a single organized religion, this includes several traditional African beliefs and philosophies such as those of the Yoruba, Ewe (Vodou) and the Bakongo. These three religious traditions (especially that of the Yoruba) have been very influential to the diasporic beliefs of the Americas such as Condomble, Santeria and voodoo. The religious capital of the Yoruba religion is at Ile Ife.
This number states the number of actual self-identifying practising primary followers of Shinto. If everyone were included who is considered Shinto by some people due to ethnic or historical categorizations, the number would be considerably higher — as high as 100 million (according to the adherents.com source used for the statistics in this section).
Zoroastrianism: 150,000-250,000,[10][11][12][13] as substantiated by the detailed discussion sections at adherents.com[14][15], although in its top-level overview list the same source provides a substantially different estimate.[e] The breakdown by major communities is as follows:
In India (the Parsis): est. 65,000 (2001 India Census: 69,601); Estimate of Zoroastrians of Indian origin: 100,000-110,000.
a)^ The source for most of these statistics is Adherents.com, updated 2008. These statistics are reportedly based on analysis of a range of sources on religious populations, for more on the methodology, please see Adherents.com's explanation.
b)^ The Adherents.com source includes Falun Gong as part of Chinese religion. The New York Times reported in 1999 that Falun Gong itself claimed "more than 100 million followers" and reported a Chinese government estimate of 70 million for the group.
c)^ Unlike the source site adherents.com, this list classifies Juche under the secular/non-religious category, since it does not fit most definitions of religion and is considered secular by its followers.
d)^Ahmadiyya consider themselves Muslim, but they are not considered Muslim by the mainstream. Adherents.com includes Druze as Muslim, but they are often considered by other sources to be a distinct religious community that is an offshoot of Islam.
e)^ The main list at adherents.com estimates 2.6 million Zoroastrianism, but its detailed section refers to "less than 200,000."
f)^ As noted at Adherents.com, Spiritism is often considered to fall within the Christianity category. This is the approach taken in the list above, which differs from the categorization used in the main list at Adherents.com.
This material is neither peer-reviewed nor otherwise accompanied by a description of methodology or an assertion of adherence to scientific methods. It relies largely or entirely upon a single source.
Please help improve this article by introducing appropriate citations of additional sources. (November 2007)
World map based on the results of a 2002 Pew Research Center study on the percentage of people who regard religion as "important"
World map showing the percentages of people who regard religion as "non-important"
Since the late 19th century the demographics of religion have changed a great deal. Some countries with a historically large Christian population have experienced a significant decline in the numbers of professed active Christians. Symptoms of the decline in active participation in Christian religious life include declining recruitment for the priesthood and monastic life, as well as diminishing attendance at church. At the same time, there has been an increase in the number of people who identify themselves as secular humanists. In many countries, such as the People's Republic of China, communist governments have discouraged religion, making it difficult to count the actual number of believers. However, after the collapse of communism in numerous countries of Eastern Europe and the former Soviet Union, religious life has been experiencing resurgence there, particularly in the forms of Neopaganism and Far Eastern religions.
Within the world's four largest religions, Christianity currently has the greatest growth by numbers and Islam has the fastest growth by percentage.[16] Following is some available data based on the work of World Christian Database and its predecessor, the World Christian Encyclopedia:
The annual growth in the world population over the same period is 1.41%.
While controversial in some respects, the results have been studied and found "highly correlated with other sources of data" but "consistently gave a higher estimate for percent Christian in comparison to other cross-national data sets" according to one study.[20]
A 2002 Pew Research Center study found that, generally, poorer nations had a larger proportion of citizens who found religion to be very important than richer nations, with the exception of the United States.[21]
References
^Remarks on the concepts of adherence and self-identification method of religious classification at Adherents.com
^Christian Science Monitor, 1998, as reported at Adherents.com site.
^ adherents.com separate "African Traditional & African Diasporic Religions" from "Primal-Indigenous", admitting large overlap. Only very rough estimates for the size of these groups are possible in any case.
^Pippa Norris, Ronald Inglehart, Sacred and Secular, Religion and Politics Worldwide, Cambridge University Press, 2007-01-06.
^ Melton, J. Gordon & Baumann, Martin, eds. (2002), Religions of the World: A Comprehensive Encyclopedia of Beliefs and Practices, Oxford: ABC-CLIO, ISBN 1-57607-223-1, p. 634
^ Hopfe, Lews M. & Woodward, Mark R, eds. (2003), Religions of the World, New York: Prentice Hall, ISBN 0-13-183007-4, p. 313
^ Eliade, Mircea & Couliano, Ioan P., eds. (1991), The Eliade Guide to World Religions, San Francisco: Harper Collins, ISBN 0-06-062145-1, p. 254
^ Palsetia, Jesse S. (2001) The Parsis of India, Leiden: Brill, ISBN 90-04-12114-5, p. 1 n. 1.
Animated history of World Religions - from the "Religion & Ethics" part of the BBC website, interactive animated view of the spread of world religions (requires Flash plug-in).