The essence of any religion lies solely in the answer to the question: why do I exist, and what is my relationship to the infinite universe that surrounds me? .. It is impossible for there to be a person with no religion (i.e. without any kind of relationship to the world) as it is for there to be a person without a heart. He may not know that he has a religion, just as a person may not know that he has a heart, but it is no more possible for a person to exist without a religion than without a heart. (Leo Tolstoy, 1879)
The principles are very simple, comprehensible and uncomplicated. They are as follows:
that there is a God who is the origin of everything;
that there is an element of this divine origin in every person, which he can diminish or increase through his way of living;
that in order for someone to increase this source he must suppress his passions and increase the love within himself;
that the practical means of achieving this consist in doing to others as you would wish to do to you.
All these principles are common to Brahmanism, Hebraism, Confucianism, Taoism, Buddhism, Christianity and Mohammedanism. (If Buddhism does not provide a definition of God, it nevertheless recognises that with which man unites and merges as he reaches Nirvana. And that something is the same origin which the other religions recognise as God.)
Religion is the definition of man’s relationship to the origin of everything, and of the purpose acquired as a result of this relationship, and of the rules of conduct that follow from this purpose. And the religion common to all, the basic principles of which are alike in all practices, fully satisfies these demands. It defines man’s relationship to God as of a part to a whole. From this relationship follows man’s purpose, which lies in increasing his spiritual qualities, and man’s purpose leads to the practical rules of the law: do to others as you would have them do unto you. (Leo Tolstoy, 1879)
Theology is the study of God. It can be understood as a rational inquiry into questions of religion.
One way to define a major world religion is by the current number of current adherents. Population numbers by religion are computed by 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.
This listing does not draw distinctions between organized world religions, which has a single belief code and religious hierarchies, and informal world religions, such as Chinese traditional religions, which are a mix of different informal religious ideas.
Christianity 2 billion
Roman Catholicism: 1.1 billion
Protestantism: 360 million
Eastern Orthodoxy: 220 million
Anglican: 84 million
Other Christians: 280 million
Islam 1.3 billion
Sunnism: 940 million
Shiism 120 million
Hinduism 900 million
Secular / Nonreligious / Agnostic / Atheist 850 million
Buddhism 360 million
Chinese traditional religion 225 million
Not a single organized religion, includes elements of Taoism, Confucianism, and traditional nonscriptural religious observance.
Primal indigenous 150 million
Not a single organized religion, includes a wide range of primarily Asian traditional or tribal religions, including Shamanism and Paganism.
African Traditional and Diasporic 95 million
Not a single organized religion, this includes traditional African beliefs such as Yoruba as well as Diasporic beliefs such as Santeria and Vodoun.
Sikhism 23 million
Juche 19 million
Not considered a religion by adherents. Juche is the political ideology taught by North Korean communists; some have argued it constitutes a religion.
Spiritism 14 million
Not a single organized religion, includes a variety of beliefs including some forms of Umbanda.
Judaism 14 million
Bahá'í Faith 6 million
Jainism 5 million
Shinto 4 million
Cao Dai 3 million
Tenrikyo 2.4 million
Neopaganism 1 million
Unitarian Universalism 800,000
Rastafarianism 700,000
Not an organized religion
Scientology 600,000
Zoroastrianism 150,000
Source of statistics: adherents.com (http://www.adherents.com/Religions_By_Adherents.html), updated 2002
Major religions have also been identified based on their importance, whether theological or temporal. The earliest Christian scholars, the first to define major religions, recognized only three religions: Christianity, Judaism, and Paganism (which they considered to encompass every other religion). Views evolved during the enlightenment, however, and, by the 19th century, Western scholars considered the five major religions to be Judaism, Christianity, Islam, Hinduism, and Buddhism. As the exposure of Westerners to other religions increased, five other religions were added to the original five: Confucianism, Taoism, Jainism, Shinto and Zoroastrianism. Later, the Bahá'í Faith was added to this list, resulting in eleven classic religions:
Bahá'í Faith
Buddhism
Christianity
Confucianism
Hinduism
Islam
Jainism
Judaism
Shinto
Taoism
Zoroastrianism
The standard modern definition of major religion comes from the classical definition, often expanding on "Christianity," and omitting Jainism and Zoroastrianism, like this list found in the New York Public Library Student Reference:
Bahá'í Faith
Buddhism
Confucianism
Hinduism
Islam
Judaism
Orthodox Eastern Church
Protestantism
Catholicism
Shinto
Taoism
http://en.wikipedia.org/wiki/Major_world_religions