Symbols representing some world religions, from left to right:
row 1: Christianity, Judaism, Hinduism
row 2: Islam, Buddhism, Shinto
row 3: Sikhism, Bahá'í Faith, Jainism

Religion is a collection of cultural systems, belief systems, and worldviews that relate humanity to spirituality and, sometimes, to moral values.^[1] Many religions have narratives, symbols, traditions and sacred histories that are intended to give meaning to life or to explain the origin of life or the universe. They tend to derive morality, ethics, religious laws or a preferred lifestyle from their ideas about the cosmos and human nature.

The word religion is sometimes used interchangeably with faith or belief system, but religion differs from private belief in that it has a public aspect^{[citation needed]}. Many religions have organized behaviors, clergy, a definition of what constitutes adherence or membership, congregations of laity, regular meetings or services for the purposes of veneration of a deity or for prayer, holy places (either natural or architectural), and/or scriptures. The practice of a religion may also include sermons, commemoration of the activities of a god or gods, sacrifices, festivals, feasts, trance, initiations, funerary services, matrimonial services, meditation, music, art, dance, public service, or other aspects of human culture. However, there are examples of religions for which some or many of these aspects of structure, belief, or practices are absent.

The development of religion has taken different forms in different cultures. Some religions place an emphasis on belief, while others emphasize practice. Some religions focus on the subjective experience of the religious individual, while others consider the activities of the religious community to be most important. Some religions claim to be universal, believing their laws and cosmology to be binding for everyone, while others are intended to be practiced only by a closely defined or localized group. In many places religion has been associated with public institutions such as education, hospitals, the family, government, and political hierarchies. Anthropologists John Monoghan and Peter Just state that, "it seems apparent that one thing religion or belief helps us do is deal with problems of human life that are significant, persistent, and intolerable. One important way in which religious beliefs accomplish this is by providing a set of ideas about how and why the world is put together that allows people to accommodate anxieties and deal with misfortune."^[2]

Some academics studying the subject have divided religions into three broad categories: world religions, a term which refers to transcultural, international faiths; indigenous religions, which refers to smaller, culture-specific or nation-specific religious groups; and new religious movements, which refers to recently developed faiths.^[3] One modern academic theory of religion, social constructionism, says that religion is a modern concept that suggests all spiritual practice and worship follows a model similar to the Abrahamic religions as an orientation system that helps to interpret reality and define human beings,^[4] and thus religion, as a concept, has been applied inappropriately to non-Western cultures that are not based upon such systems, or in which these systems are a substantially simpler construct.

Etymology[link]

Religion (from O.Fr. religion "religious community," from L. religionem (nom. religio) "respect for what is sacred, reverence for the gods,"^[5] "obligation, the bond between man and the gods"^[6]) is derived from the Latin religiō, the ultimate origins of which are obscure. One possibility is derivation from a reduplicated *le-ligare, an interpretation traced to Cicero connecting lego "read", i.e. re (again) + lego in the sense of "choose", "go over again" or "consider carefully". Modern scholars such as Tom Harpur and Joseph Campbell favor the derivation from ligare "bind, connect", probably from a prefixed re-ligare, i.e. re (again) + ligare or "to reconnect," which was made prominent by St. Augustine, following the interpretation of Lactantius.^[7][8] The medieval usage alternates with order in designating bonded communities like those of monastic orders: "we hear of the 'religion' of the Golden Fleece, of a knight 'of the religion of Avys'".^[9]

According to the philologist Max Müller, the root of the English word "religion", the Latin religio, was originally used to mean only "reverence for God or the gods, careful pondering of divine things, piety" (which Cicero further derived to mean "diligence").^[10][11] Max Müller characterized many other cultures around the world, including Egypt, Persia, and India, as having a similar power structure at this point in history. What is called ancient religion today, they would have only called "law".^[12]

Many languages have words that can be translated as "religion", but they may use them in a very different way, and some have no word for religion at all. For example, the Sanskrit word dharma, sometimes translated as "religion", also means law. Throughout classical South Asia, the study of law consisted of concepts such as penance through piety and ceremonial as well as practical traditions. Medieval Japan at first had a similar union between "imperial law" and universal or "Buddha law", but these later became independent sources of power.^[13][14]

There is no precise equivalent of "religion" in Hebrew, and Judaism does not distinguish clearly between religious, national, racial, or ethnic identities.^[15] One of its central concepts is "halakha", sometimes translated as "law"", which guides religious practice and belief and many aspects of daily life.

The use of other terms, such as obedience to God or Islam are likewise grounded in particular histories and vocabularies.^[16]

Major denominations and religions of the world

Origins[link]

There are a number of theories regarding the origins of religion. Greg M. Epstein, a Humanist chaplain at Harvard University, states that "essentially all the world's major religions were founded on the principle that divine beings or forces can promise a level of justice in a supernatural realm that cannot be perceived in this natural one."^[17] According to anthropologists John Monaghan and Peter Just,

Many of the great world religions appear to have begun as revitalization movements of some sort, as the vision of a charismatic prophet fires the imaginations of people seeking a more comprehensive answer to their problems than they feel is provided by everyday beliefs. Charismatic individuals have emerged at many times and places in the world. It seems that the key to long-term success – and many movements come and go with little long-term effect – has relatively little to do with the prophets, who appear with surprising regularity, but more to do with the development of a group of supporters who are able to institutionalize the movement.^[18]

Religious movements[link]

In the 19th and 20th centuries, the academic practice of comparative religion divided religious belief into philosophically defined categories called "world religions." However, some recent scholarship has argued that not all types of religion are necessarily separated by mutually exclusive philosophies, and furthermore that the utility of ascribing a practice to a certain philosophy, or even calling a given practice religious, rather than cultural, political, or social in nature, is limited.^[19][20][21] The current state of psychological study about the nature of religiousness suggests that it is better to refer to religion as a largely invariant phenomenon that should be distinguished from cultural norms (i.e. "religions").^[22] The list of religious movements given here is therefore an attempt to summarize the most important regional and philosophical influences on local communities, but it is by no means a complete description of every religious community, nor does it explain the most important elements of individual religiousness.

The four largest religious groups by population, estimated to account for between 5 and 7 billion people, are Christianity, Islam, Buddhism, and Hinduism (with the relative numbers for Buddhism and Hinduism dependent on the extent of syncretism).

The patriarch Abraham (by József Molnár)

• Abrahamic religions are monotheistic religions which believe they descend from Abraham.

• Judaism is the oldest Abrahamic religion, originating in the people of ancient Israel and Judea. Judaism is based primarily on the Torah, a text which some Jews believe was handed down to the people of Israel through the prophet Moses. This along with the rest of the Hebrew Bible and the Talmud are the central texts of Judaism. The Jewish people were scattered after the destruction of the Temple in Jerusalem in 70 CE. Today there are about 13 million Jews, about 40 per cent living in Israel and 40 per cent in the United States.^[26]
• Christianity is based on the life and teachings of Jesus of Nazareth (1st century) as presented in the New Testament. The Christian faith is essentially faith in Jesus as the Christ, the Son of God, and as Savior and Lord. Almost all Christians believe in the Trinity, which teaches the unity of Father, Son (Jesus Christ), and Holy Spirit as three persons in one Godhead. Most Christians can describe their faith with the Nicene Creed. As the religion of Byzantine Empire in the first millennium and of Western Europe during the time of colonization, Christianity has been propagated throughout the world. The main divisions of Christianity are, according to the number of adherents:
  • Catholic Church, headed by the Pope in Rome, is a communion of the Western church and 22 Eastern Catholic churches.
  • Protestantism, separated from the Catholic Church in the 16th-century Reformation and split in many denominations,
  • Eastern Christianity which include Eastern Orthodoxy, Oriental Orthodoxy and the Church of the East.

There are other smaller groups, such as Jehovah's Witnesses and the Latter Day Saint movement, whose inclusion in Christianity is sometimes disputed.

Muslims praying around Kaaba, the most sacred site in Islam

• Islam refers to the religion taught by the Islamic prophet Muhammad, a major political and religious figure of the 7th century CE. Islam is the dominant religion of northern Africa, the Middle East, and South Asia. As with Christianity, there is no single orthodoxy in Islam but a multitude of traditions which are generally categorized as Sunni and Shia, although there are other minor groups as well. Wahhabi is the dominant Muslim schools of thought in the Kingdom of Saudi Arabia. There are also several Islamic republics, including Iran, which is run by a Shia Supreme Leader.
• The Bahá'í Faith was founded in the 19th century in Iran and since then has spread worldwide. It teaches unity of all religious philosophies and accepts all of the prophets of Judaism, Christianity, and Islam as well as additional prophets including its founder Bahá'u'lláh.
• Smaller regional Abrahamic groups, including Samaritanism (primarily in Israel and the West Bank), the Rastafari movement (primarily in Jamaica), and Druze (primarily in Syria and Lebanon).

Hindu statue of Rama in Kalaram Temple (India)

• Indian religions are practiced or were founded in the Indian subcontinent.
  • Hinduism is a synecdoche describing the similar philosophies of Vaishnavism, Shaivism, and related groups practiced or founded in the Indian subcontinent. Concepts most of them share in common include karma, caste, reincarnation, mantras, yantras, and darśana.^[27] Hinduism is the most ancient of still-active religions,^[28][29] with origins perhaps as far back as prehistoric times.^[30] Hinduism is not a monolithic religion but a religious category containing dozens of separate philosophies amalgamated as Sanātana Dharma, which is the name with whom Hinduism has been known throughout history by its followers.
  • Jainism, taught primarily by Parsva (9th century BCE) and Mahavira (6th century BCE), is an ancient Indian religion that prescribes a path of non-violence for all forms of living beings in this world. Jains are found mostly in India.
  • Buddhism was founded by Siddhattha Gotama in the 6th century BCE. Buddhists generally agree that Gotama aimed to help sentient beings end their suffering (dukkha) by understanding the true nature of phenomena, thereby escaping the cycle of suffering and rebirth (saṃsāra), that is, achieving Nirvana.
    • Theravada Buddhism, which is practiced mainly in Sri Lanka and Southeast Asia alongside folk religion, shares some characteristics of Indian religions. It is based in a large collection of texts called the Pali Canon.
    • Under the heading of Mahayana (the "Great Vehicle") fall a multitude of doctrines which began their development in China and are still relevant in Vietnam, in Korea, in Japan, and to a lesser extent in Europe and the United States. Mahayana Buddhism includes such disparate teachings as Zen, Pure Land, and Soka Gakkai.
    • Vajrayana Buddhism, sometimes considered a form of Mahayana, was developed in Tibet and is still most prominent there and in surrounding regions.
    • Two notable new Buddhist sects are Hòa Hảo and the Dalit Buddhist movement, which were developed separately in the 20th century.
  • Sikhism is a monotheistic religion founded on the teachings of Guru Nanak and ten successive Sikh Gurus in 15th century Punjab. Sikhs are found mostly in India.
  • There are dozens of new religious movements within Indian religions and Hindu reform movements, such as Ayyavazhi, Swaminarayan Faith and Ananda Marga.

Zoroastrian Fire Temple

• Iranian religions are ancient religions whose roots predate the Islamization of Greater Iran. Nowadays these religions are practiced only by minorities.
  • Zoroastrianism is a religion and philosophy based on the teachings of prophet Zoroaster in the 6th century BC. The Zoroastrians worship the Creator Ahura Mazda. In Zoroastrianism good and evil have distinct sources, with evil trying to destroy the creation of Mazda, and good trying to sustain it.
  • Mandaeism is a monotheistic religion with a strongly dualistic worldview. Mandaeans are sometime labeled as the "Last Gnostics".
  • Kurdish religions include the traditional beliefs of the Yazidi, Alevi, and Ahl-e Haqq. Sometimes these are labeled Yazdânism.

Incense burner in China

• Folk religion is a term applied loosely and vaguely to less-organized local practices. It is also called paganism, shamanism, animism, ancestor worship, matriarchal religion, or totemism, although not all of these elements are necessarily present in local belief systems. The category of "folk religion" can generally include anything that is not part of an organization. Modern neopagan movement draws on folk religion for inspiration to varying degrees.
  • African traditional religion is a category including any type of religion practiced in Africa before the arrival of Islam and Christianity, such as Yoruba religion or San religion. There are many varieties of religions developed by Africans in the Americas derived from African beliefs, including Santería, Candomblé, Umbanda, Vodou, and Oyotunji.
  • Folk religions of the Americas include Aztec religion, Inca religion, Maya religion, and modern Catholic beliefs such as the Virgin of Guadalupe. Native American religion is practiced across the continent of North America.
  • Australian Aboriginal culture contains a mythology and sacred practices characteristic of folk religion.
  • Chinese folk religion, practiced by Chinese people around the world, is a primarily social practice including popular elements of Confucianism and Taoism, with some remnants of Mahayana Buddhism. Most Chinese do not identify as religious due to the strong Maoist influence on the country in recent history, but adherence to religious ceremonies remains common. New religious movements include Falun Gong and I-Kuan Tao.
  • Traditional Korean religion is a syncretic mixture of Mahayana Buddhism and Korean shamanism. Unlike Japanese Shinto, Korean shamanism was never codified and Buddhism was never made a social necessity. In some areas these traditions remain prevalent, but Korean-influenced Christianity is also influential in society and politics in South Korea.
  • Traditional Japanese religion is a mixture of Mahayana Buddhism and ancient indigenous practices which were codified as Shinto in the 19th century. Japanese people retain nominal attachment to both Buddhism and Shinto through social ceremonies, but irreligion is common.

A Modern-style Unitarian Universalist sanctuary

• A variety of new religious movements still practiced today have been founded in many other countries besides Japan and the United States, including:
  • Shinshūkyō is a general category for a wide variety of religious movements founded in Japan since the 19th century. These movements share almost nothing in common except the place of their founding. The largest religious movements centered in Japan include Soka Gakkai, Tenrikyo, and Seicho-No-Ie among hundreds of smaller groups.
  • Cao Đài is a syncretistic, monotheistic religion, established in Vietnam in 1926.
  • Unitarian Universalism is a religion characterized by support for a "free and responsible search for truth and meaning," and has no accepted creed or theology.
  • Scientology teaches that people are immortal beings who have forgotten their true nature. Its method of spiritual rehabilitation is a type of counseling known as auditing, in which practitioners aim to consciously re-experience painful or traumatic events in their past in order to free themselves of their limiting effects.
  • Eckankar is a religion with the purpose of making God an everyday reality in one's life.

Sociological classifications of religious movements suggest that within any given religious group, a community can resemble various types of structures, including "churches", "denominations", "sects", "cults", and "institutions".

The Hindu population of South Asia comprises about 2,000 castes.^[31] According to some Hindu literature, there are 330 million (including local and regional) Hindu deities.^[32]

Types of religion[link]

Some scholars classify religions as either universal religions that seek worldwide acceptance and actively look for new converts, or ethnic religions that are identified with a particular ethnic group and do not seek converts.^[33] Others reject the distinction, pointing out that all religious practices, whatever their philosophical origin, are ethnic because they come from a particular culture.^[34][35][36]

Issues in religion[link]

Interfaith cooperation[link]

Because religion continues to be recognized in Western thought as a universal impulse, many religious practitioners have aimed to band together in interfaith dialogue, cooperation, and religious peacebuilding. The first major dialogue was the Parliament of the World's Religions at the 1893 Chicago World's Fair, which remains notable even today both in affirming "universal values" and recognition of the diversity of practices among different cultures. The 20th century has been especially fruitful in use of interfaith dialogue as a means of solving ethnic, political, or even religious conflict, with Christian-Jewish reconciliation representing a complete reverse in the attitudes of many Christian communities towards Jews.

Recent interfaith initiatives include "A Common Word", launched in 2007 and focused on bringing Muslim and Christian leaders together,^[37] the "C1 World Dialogue",^[38] the "Common Ground" initiative between Islam and Buddhism,^[39] and a United Nations sponsored "World Interfaith Harmony Week".^[40][41]

Secularism and irreligion[link]

The terms "atheist" (lack of belief in any gods) and "agnostic" (belief in the unknowability of the existence of gods), though specifically contrary to theistic (e.g. Christian, Jewish, and Muslim) religious teachings, do not by definition mean the opposite of "religious". There are religions (including Buddhism and Taoism), in fact, that classify some of their followers as agnostic, atheistic, or nontheistic. The true opposite of "religious" is the word "irreligious". Irreligion describes an absence of any religion; antireligion describes an active opposition or aversion toward religions in general.

Critics of religion consider it to be to be outdated, harmful to the individual (e.g. brainwashing of children, faith healing, circumcision), harmful to society (e.g. holy wars, terrorism, wasteful distribution of resources), to impede the progress of science, and to encourage immoral acts (e.g. blood sacrifice, discrimination against homosexuals and women). A major criticism of many religions is that they require beliefs that are irrational, unscientific, or unreasonable, because religious beliefs and traditions lack scientific or rational foundations.

As religion became a more personal matter in Western culture, discussions of society found a new focus on political and scientific meaning, and religious attitudes (dominantly Christian) were increasingly seen as irrelevant for the needs of the European world. On the political side, Ludwig Feuerbach recast Christian beliefs in light of humanism, paving the way for Karl Marx's famous characterization of religion as "the opium of the people". Meanwhile, in the scientific community, T.H. Huxley in 1869 coined the term "agnostic," a term—subsequently adopted by such figures as Robert Ingersoll—that, while directly conflicting with and novel to Christian tradition, is accepted and even embraced in some other religions. Later, Bertrand Russell told the world Why I Am Not a Christian, which influenced several later authors to discuss their breakaway from their own religious uprbringings from Islam to Hinduism.

Some modern-day critics, such as Bryan Caplan, hold that religion lacks utility in human society; they may regard religion as irrational.^[42] Nobel Peace Laureate Shirin Ebadi has spoken out against undemocratic Islamic countries justifying "oppressive acts" in the name of Islam.^[43]

Related forms of thought[link]

Religion and superstition[link]

Superstition has been described as "the incorrect establishment of cause and effect" or a false conception of causation.^[44] Religion is more complex and includes social institutions and morality. But religions may include superstitions or make use of magical thinking. Adherents of one religion sometimes think of other religions as superstition.^[45][46] Some atheists, deists, and skeptics regard religious belief as superstition.

Greek and Roman pagans, who saw their relations with the gods in political and social terms, scorned the man who constantly trembled with fear at the thought of the gods (deisidaimonia), as a slave might fear a cruel and capricious master. The Romans called such fear of the gods superstitio.^[47] Early Christianity was outlawed as a superstitio Iudaica, a "Jewish superstition", by Domitian in the 80s AD. In AD 425, when Rome had become Christian, Theodosius II outlawed pagan traditions as superstitious.

The Roman Catholic Church considers superstition to be sinful in the sense that it denotes a lack of trust in the divine providence of God and, as such, is a violation of the first of the Ten Commandments. The Catechism of the Catholic Church states that superstition "in some sense represents a perverse excess of religion" (para. #2110). "Superstition," it says, "is a deviation of religious feeling and of the practices this feeling imposes. It can even affect the worship we offer the true God, e.g., when one attributes an importance in some way magical to certain practices otherwise lawful or necessary. To attribute the efficacy of prayers or of sacramental signs to their mere external performance, apart from the interior dispositions that they demand is to fall into superstition. Cf. Matthew 23:16-22" (para. #2111)

Myth[link]

The word myth has several meanings.

1. A traditional story of ostensibly historical events that serves to unfold part of the world view of a people or explain a practice, belief, or natural phenomenon;
2. A person or thing having only an imaginary or unverifiable existence; or
3. A metaphor for the spiritual potentiality in the human being.^[48]

Urarina shaman, 1988

Ancient polytheistic religions, such as those of Greece, Rome, and Scandinavia, are usually categorized under the heading of mythology. Religions of pre-industrial peoples, or cultures in development, are similarly called "myths" in the anthropology of religion. The term "myth" can be used pejoratively by both religious and non-religious people. By defining another person's religious stories and beliefs as mythology, one implies that they are less real or true than one's own religious stories and beliefs. Joseph Campbell remarked, "Mythology is often thought of as other people's religions, and religion can be defined as mis-interpreted mythology."^[49]

In sociology, however, the term myth has a non-pejorative meaning. There, myth is defined as a story that is important for the group whether or not it is objectively or provably true. Examples include the death and resurrection of Jesus, which, to Christians, explains the means by which they are freed from sin and is also ostensibly a historical event. But from a mythological outlook, whether or not the event actually occurred is unimportant. Instead, the symbolism of the death of an old "life" and the start of a new "life" is what is most significant. Religious believers may or may not accept such symbolic interpretations.

Religion and health[link]

Mayo Clinic researchers examined the association between religious involvement and spirituality, and physical health, mental health, health-related quality of life, and other health outcomes. The authors reported that: "Most studies have shown that religious involvement and spirituality are associated with better health outcomes, including greater longevity, coping skills, and health-related quality of life (even during terminal illness) and less anxiety, depression, and suicide."^[50]

Religion and violence[link]

The Crusades were a series of a military campaigns fought mainly between Christian Europe and Muslims. Shown here is a battle scene from the First Crusade. They were inspired at the jihad of the Islam civilization.

Charles Selengut characterizes the phrase "religion and violence" as "jarring", asserting that "religion is thought to be opposed to violence and a force for peace and reconciliation. He acknowledges, however, that "the history and scriptures of the world's religions tell stories of violence and war as they speak of peace and love."^[51]

Hector Avalos argues that, because religions claim divine favor for themselves, over and against other groups, this sense of righteousness leads to violence because conflicting claims to superiority, based on unverifiable appeals to God, cannot be adjudicated objectively.^[52]

Critics of religion Christopher Hitchens and Richard Dawkins go further and argue that religions do tremendous harm to society by using violence to promote their goals, in ways that are endorsed and exploited by their leaders.^{[53][page needed][54][page needed]}

Regina Schwartz argues that all monotheistic religions are inherently violent because of an exclusivism that inevitably fosters violence against those that are considered outsiders.^[55] Lawrence Wechsler asserts that Schwartz isn't just arguing that Abrahamic religions have a violent legacy, but that the legacy is actually genocidal in nature.^[56]

Byron Bland asserts that one of the most prominent reasons for the "rise of the secular in Western thought" was the reaction against the religious violence of the 16th and 17th centuries. He asserts that "(t)he secular was a way of living with the religious differences that had produced so much horror. Under secularity, political entities have a warrant to make decisions independent from the need to enforce particular versions of religious orthodoxy. Indeed, they may run counter to certain strongly held beliefs if made in the interest of common welfare. Thus, one of the important goals of the secular is to limit violence."^[57]

Nonetheless, believers have used similar arguments when responding to atheists in these discussions, pointing to the widespread imprisonment and mass murder of individuals under atheist states in the twentieth century:^[58][59][60]

In response to such a line of argument, however, author Sam Harris writes:

"The problem with fascism and communism, however, is not that they are too critical of religion; the problem is that they are too much like religions. Such regimes are dogmatic to the core and generally give rise to personality cults that are indistinguishable from cults of religious hero worship. Auschwitz, the gulag and the killing fields were not examples of what happens when human beings reject religious dogma; they are examples of political, racial and nationalistic dogma run amok. There is no society in human history that ever suffered because its people became too reasonable."^[61]

Richard Dawkins has stated that Stalin's atrocities were influenced not by atheism but by dogmatic Marxism,^[62] and concludes that while Stalin and Mao happened to be atheists, they did not do their deeds in the name of atheism.^[63] On other occasions, Dawkins has replied to the argument that Adolf Hitler and Josef Stalin were antireligious with the response that Hitler and Stalin also grew moustaches, in an effort to show the argument as fallacious.^[64] Instead, Dawkins argues in The God Delusion that "What matters is not whether Hitler and Stalin were atheists, but whether atheism systematically influences people to do bad things. There is not the smallest evidence that it does."^[65] D'Souza responds that an individual need not explicitly invoke atheism in committing atrocities if it is already implied in his worldview, as is the case in Marxism.^[66]

Religion and the law[link]

This section requires expansion.

There are laws and statutes that make reference to religion.^[67] This has led scholar Winnifred Sullivan to claims that religious freedom is impossible.^[68] Others argue that the Western legal principle of separation of church and state tends to engender a new, more inclusive civil religion.^[69]

Religion and science[link]

Religious knowledge, according to religious practitioners, may be gained from religious leaders, sacred texts, scriptures, or personal revelation. Some religions view such knowledge as unlimited in scope and suitable to answer any question; others see religious knowledge as playing a more restricted role, often as a complement to knowledge gained through physical observation. Adherents to various religious faiths often maintain that religious knowledge obtained via sacred texts or revelation is absolute and infallible and thereby creates an accompanying religious cosmology, although the proof for such is often tautological and generally limited to the religious texts and revelations that form the foundation of their belief.

In contrast, the scientific method gains knowledge by testing hypotheses to develop theories through elucidation of facts or evaluation by experiments and thus only answers cosmological questions about the universe that can be observed and measured. It develops theories of the world which best fit physically observed evidence. All scientific knowledge is subject to later refinement, or even outright rejection, in the face of additional evidence. Scientific theories that have an overwhelming preponderance of favorable evidence are often treated as de facto verities in general parlance, such as the theories of general relativity and natural selection to explain respectively the mechanisms of gravity and evolution.