What constitutes a religion is subject to much dispute in the field of theology and among ordinary people. We might begin by defining religion as a system of beliefs based on humanity's attempt to explain the universe and natural phenomena[?], often involving one or more deities or other supernatural forces. Religious adherents tend to gather together to celebrate holy days, recite or chant scripture and to pray, but solitary practice like meditation is also usually just as important. Most religions also have a code of laws to be followed, like the Ten Commandments of Old Testament, and some have specific texts they hold as sacred, and totally different from other writings. Another definition of religion is that a religion's belief system is not an attempt to define such things, but rather a source from which definition flows. An analogy would be that of a pitcher of water - rather than seeing the pitcher as a way to explain the containment of existing water, it would be seen as the source of a supply of new water.
Two identifying features of all religions are that to some extent they all (a) require faith and (b) seek to organize and guide the thoughts and actions of their adherents. Because of this, some people contend that all religions are to some degree both unempirical (see empiricism) and dogmatic, and are therefore to be distrusted. As they see it, a system of thought that is purely rational would be a science rather than a religion, and a system that is not in the least dogmatic would be unable to guide its adherents in any way.
Many Western people nowadays prefer to use the term spirituality for their position. This may reflect a disillusionment with organised religion which unless it stays small scale, must grapple with worldly pressures of power and economics where ideals so often become corrupted. Some historically Christian Western countries, particularly in Europe, show declining recruitment for Priesthoods and monasteries, and studies in the UK show a fast-diminishing attendance at churches, synagogues etc (except among charismatics). However, similar studies of US Christianity show only minor fluctuations in attendance over several decades, and Christianity in Africa and Asia is experiencing explosive growth. Still, even in areas where religious institutions are struggling, studies that look further and examine people's beliefs and practices without defining religion strictly in terms of organisation membership, find that spiritual beliefs are flourishing, and often extend to cherished family and community customs. New variations of religions are being constantly generated, showing that the religious impulse is not dying, but taking new forms.
There are several scientific approaches to religion to answer questions such as why religious belief is ubiquitous in every society. In neurology, work by scientists such as Ramachandran and his colleagues from the University of California, San Diego  (http://serendip.brynmawr.edu/bb/neuro/neuro01/web2/Eguae) has found evidence of brain circuitry in the temporal lobe that gives rises to religious experiences. In sociology, Rodney Stark[?] has looked at the social forces that have caused religions to grow and the features of religions that have been most successful. In evolutionary psychology, scientists consider the survival advantages that religion might have had in the hunter-gatherer societies.
Religions are systems of belief which typically deal with
Although most cognitive psychologists agree that all religious ideas have the same origin, it is often useful to classify religions by their stucture or "concent." Following are several ways to classify religions:
Adherents of particular religions deal with the (more or less) divergent doctrines and practices espoused by other religions in several ways. Examples of all three exist within most major religious systems. People with exclusivist[?] beliefs typically explain other religions as either in error, or as corruptions or counterfeits of the true faith. People with inclusivist[?] beliefs recognize some truth in all faith systems, highlighting agreements and minimizing differences, but see their own faith as in some way ultimate. People with pluralist[?] beliefs make no distinction between faith systems, viewing each one as valid within a particular culture. Pluralists and inclusivists may borrow from more than one faith system for their own religious practice.
Many religions have been deeply influenced by charismatic leaders, such as Jesus Christ, Martin Luther, Billy Graham, Adi Sankara, Ramakrishna Paramahamsa[?], Swami Vivekanada[?], Sai Baba, Joseph Smith, Muhammad, Gautama Buddha, etc. These leaders may be the central teacher in the religion, like Muhammad, Jesus or Gautama. Or they might be reformers, like Martin Luther. Or they may be merely prominent persons like Billy Graham--who is an influential speaker but not the head of a large organization or movement.
The Founders of some of the major world religions include Abraham and Moses for Judaism, Zoroaster for Zoroastrianism, Gautama Buddha for Buddhism, Jesus Christ for Christianity, Muhammad for Islám, and Bahá'u'lláh for the Bahá'í Faith.
The origin of religion in general and for particular religions is usually controversial, since religions often claim to have been derived directly from information supplied by god(s) to chosen human messenger(s). Followers of the religion (by definition) accept the claims, either literally or in a metaphorical, or partial fashion. Although followers of a religion, although they may hold strong belief, may also be interested in looking at possible human origins for religious events, together with non-religious enquirers.
Religion was practiced long before the invention of writing, as paintings and pottery shows in images. Indeed, heavy deposits of pollen in Neanderthal graves suggest that even these early humans buried their dead along with flowers. Stories ("texts") passed orally between people and from one generation to the next. Religion may well have originated in stories created to account for the great questions of life, for comfort, to keep records of a people's history, and for entertainment. Stories in traditional societies unite adults and children in community, although it is possible that atheists (those who do not believe in any deities; strong atheists[?] believe no deities exist, while weak atheists[?] merely lack belief in deities) or agnostics (those who believe we cannot know if there are any deities) always existed as well. Evidence of very early human prehistory is scanty and it is best not to over interpret archaeological remains: for example it is generally thought that bones painted with red ochre (a red mud thay may link to blood colour to symbolize life) and buried with personal possessions, suggest a belief in the afterlife. It could also be because using the dead person's possessions was believed to be bad luck. For a more contemporary example, consider a future archaeologist digging the remains of a Star Wars fan's bedroom and the possible erroneous interpretations of such a find.
Evidence for early civilisations' religious ideas can be found similarly in elaborate burial practices in which valuable objects were left with the deceased, intended for use in an afterlife or to appease the gods. This custom has clearer motives as it is usually accompanied by tomb paintings showing a belief of afterlife. It reached a spectacular form with the creation of the pyramids of Giza and the other great tombs of ancient Egypt; the Sumerian royal burials, and other prehistoric (pre-written records) monument builders.
Religions created in modern times are often reasonably well documented (for example, Scientology.) Minor religions have been called cults and still are, while many scholars use the term New Religious Movement (NRM). Reasons for the creation of religions are many, including a range from idealism to a desire to obtain wealth and power over others; the two may combine in interesting ways. It's easy to speculate that similar forces were at work in the creation of earlier religions. Once a religious community increases in size and gains widespread recognition, it has to negotiate with the governing social group, the State. At this point material or political ambitions are more likely to be dominant.
Hostility to religion can have various reasons. Karl Marx famously defined religion as a social opiate, and from outside it certainly appears to operate as such, but wholesale condemnation overlooks the great numbers and scale of visionary inspirations that religions provide for compassion, practical charity and moral restraint.
When wars are aggravated or caused by religious issues they tend to be worse in their atrocities. Yet Abram Maslow's[?] research after World War II showed that Holocaust survivors tended to be those who held strong religious beliefs (not necessarily temple attendance etc). Humanistic Psychology went on to investigate how religious or spiritual identity links with longer lifespan and better health. Humans may particularly need religious ideas because they serve various emotional needs such as the need to feel loved, the need to belong to homogenous groups, the need for understandable explanations or the need for justice.
Recent advances in cognitive psychology and neuropsychology[?] suggest that religion might have its origins in the workings of the brain itself. Pascal Boyer[?]'s book, Religion Explained[?], attemtps to explain religion through cognitive psychology.
Ancient polytheistic religions, such as those of ancient Greece, ancient Rome, the Vikings, etc., are often studied under the heading of mythology. Religions of pre-industrial peoples, or cultures in development to industrial conditions, are similarly observed by the anthropology of religion. Mythology can be a term used pejoratively by religious and non-religious people both (the religious person will in this case define another religion's stories as mythology). Here myths are treated as fantasies, or "mere" stories. But the study of religions, and the investigation of myths by psychology, not to mention how some myths turn out to have historical verification, has brought about a mixed, almost contradictory use of the term: some NRMs (New Religious Movements) such as Neopaganism actively research and use myths from older religions, both those that still exist and those that have disappeared.
The dominance of monotheism among influential Western scholars of religion, and theologians, proposed a division into monotheistic and polytheistic faiths. The classification fails with a religion that places minute emphasis on gods but more importance on mankind's growing ability to understand the ineffable (like Theravada Buddhism). Christianity claims to be monotheistic, although some writers find this idea problematic since Christian doctrine has developed a notion of God as one essence in three persons (Father, Son and Holy Spirit), explained in the doctrine of the Trinity. The monotheism of Islam and Judaism is much more clear cut, although very early sources for both Allah and Yahweh show signs of polytheistic origins or forerunners, which does not at all deny or contradict their sole Deity status once the religion became established. Neopaganism (including Wicca and Asatru), a group of religions generally considered to be polytheistic, is also difficult to classify neatly. While adherents worship a diverse pantheon of gods and goddesses, a great many of them believe those personalities to be facets of a single Divine entity. The Japanese national religion, Shinto, is often said to be polytheistic.
Some religions have secondary deities, which is straightforward in Hinduism, but less so for those Christians who venerate Mary as Theotokos (Mother of God). Mary has often attracted such a massive devotion by the faithful that the Church has been careful to clearly define her status: Christians in the Catholic and Orthodox traditions are instructed that she is to be venerated but not worshipped, and that Jesus Christ is eternally begotten of the Father, and the Creator of his strictly human mother. (see also: Third Ecumenical Council, Seventh Ecumenical Council.) Many mystics have asserted the female aspect of Deity but apart from Hinduism this has not been regarded as mainstream by major world religions for several centuries. Goddess is routinely recognised in Hindu Mahadevi, Mahayana Buddhism, Western Paganism and Goddess Spirituality.
Christianity, Mahayana Buddhism, and most Hinduisms also recognize the existence of lesser spiritual beings: angels and demons. These may play a more or less elaborate role, but they are not worshipped as gods. In Christian Catholicism and Eastern Orthodoxy, Mary and the saints have especially important roles as intercessors and personal guardians. They are venerated and asked for prayers because their exemplary lives suggest that they are in the presence of God in Heaven. Mahayana Buddhism's lesser deities embody psychological forces, whether as guides, examples or antagonists with whom to learn power and skill. The division between Deity, deity, minor deity, angel, demon, nature spirit, ancestor or hero, is not clear cut, but developed pragmatically.
Deities both great and lesser are part of practices like transcendental psychology (which looks at the psychology of the spiritual) and therapies like Jungianism. Jung found an underworld of mythological drama in the backstage areas of the mind: in particular, he proposed that our ideas and feelings are shaped by spiritual archetypes, recurring models such as God, the Old Man, or the Mother which have become a part of our collective unconscious through ages of evolution. The New Age Movement, a late 20th century culture of eclectic beliefs in millennial change, healing traditions, alternative realities, also draws on these mythological images.
But it is important to distinguish a spiritual psychology that explores a map of the self, which goes so deep and far that it recognises divine shapes, from a religion or spirituality that explores a relationship between human self and an Other, the divine. The distinction asks whether there is dialogue between two or more with genuine voice and influence coming from the other (Martin Buber[?]'s I and Thou), or whether there is a journey in which the self encounters profound symbolic experiences. As the opening definition tells us, religion is about linking.
See also this listing of various religions: religions of the world