Atheism is the rejection of an assertion that a deity exists. in : "The terms ATHEISM and AGNOSTICISM lend themselves to two different definitions. The first takes the privative a both before the Greek theos (divinity) and gnosis (to know) to mean that atheism is simply the absence of belief in the gods and agnosticism is simply lack of knowledge of some specified subject matter. The second definition takes atheism to mean the explicit denial of the existence of gods and agnosticism as the position of someone who, because the existence of gods is unknowable, suspends judgment regarding them ... The first is the more inclusive and recognizes only two alternatives: Either one believes in the gods or one does not. Consequently, there is no third alternative, as those who call themselves agnostics sometimes claim. Insofar as they lack belief, they are really atheists. Moreover, since the absence of belief is the cognitive position in which everyone is born, the burden of proof falls on those who advocate religious belief. The proponents of the second definition, by contrast, regard the first definition as too broad because it includes uninformed children along with aggressive and explicit atheists. Consequently, it is unlikely that the public will adopt it."Most dictionaries (see the OneLook query for "atheism" ) first list one of the more narrow definitions. – entry by Vergilius Ferm In its strictest definition, positive atheism is the position that there are absolutely no deities that exist, while negative atheism is the position that there are probably no deities that exist, but does not state that there are none.: "As commonly understood, atheism is the position that affirms the nonexistence of God. So an atheist is someone who disbelieves in God, whereas a theist is someone who believes in God. Another meaning of 'atheism' is simply nonbelief in the existence of God, rather than positive belief in the nonexistence of God. ... an atheist, in the broader sense of the term, is someone who disbelieves in every form of deity, not just the God of traditional Western theology." The English term 'atheist' was used at least as early as the sixteenth century and atheistic ideas and their influence have a longer history.

Philosophical atheist thought began to appear in Europe and Asia in the sixth or fifth century BCE. In ancient Greece, playwrights expressed doubt regarding the existence of gods and ancient India had an antireligious philosophical school, Charvaka. Materialistic philosophy was produced by the atomists Leucippus and Democritus in 5th century BCE, who explained the world in terms of the movements of atoms moving in infinite space.

The Enlightenment fueled skepticism and secularism against religion in Europe.

Etymology

In early ancient Greek, the adjective (, from the privative ἀ- + 'god') meant 'godless'. It was first used as a term of censure roughly meaning 'ungodly' or 'impious'. In the 5th century BCE, the word began to indicate more deliberate and active godlessness in the sense of "severing relations with the gods" or "denying the gods". The term () then came to be applied against those who impiously denied or disrespected the local gods, even if they believed in other gods. Modern translations of classical texts sometimes render as 'atheistic'. As an abstract noun, there was also (), 'atheism'. Cicero transliterated the Greek word into the Latin . The term found frequent use in the debate between early Christians and Hellenists, with each side attributing it, in the pejorative sense, to the other.

The term atheist (from the French ), in the sense of "one who ... denies the existence of God or gods", predates atheism in English, being first found as early as 1566, and again in 1571.Rendered as Atheistes: Translated from Latin. Atheist as a label of practical godlessness was used at least as early as 1577.

The term atheism was derived from the French , and appears in English about 1587.Rendered as Athisme: An earlier work, from about 1534, used the term atheonism.The Oxford English Dictionary also records an earlier, irregular formation, atheonism, dated from about 1534. The later and now obsolete words athean and atheal are dated to 1611 and 1612 respectively.

Related words emerged later: deist in 1621, theist in 1662, deism in 1675, and theism in 1678."Secondly, that nothing out of nothing, in the sense of the atheistic objectors, viz. that nothing, which once was not, could by any power whatsoever be brought into being, is absolutely false; and that, if it were true, it would make no more against theism than it does against atheism" Cudworth, Ralph. The true intellectual system of the universe. 1678. Chapter V Section II p. 73 Deism and theism changed meanings slightly around 1700 due to the influence of atheism; deism was originally used as a synonym for today's theism but came to denote a separate philosophical doctrine.

Atheism was first used to describe a self-avowed belief in late 18th-century Europe, specifically denoting disbelief in the monotheistic Abrahamic god. In the 20th century, globalization contributed to the expansion of the term to refer to disbelief in all deities, though it remains common in Western society to describe atheism as "disbelief in God".

Indian philosophy

In the East, a contemplative life not centered on the idea of deities began in the sixth century BCE with the rise of Jainism, Buddhism, and various sects of Hinduism in India, and of Taoism in China. These religions offered a philosophic and salvific path not involving deity worship. Deities are not seen as necessary to the salvific goal of the early Buddhist tradition, and that tradition reflects disbelief in a supreme god or a creator god(s). Some Buddhist philosophers assert that belief in an eternal creator god is a distraction from the central task of the religious life, and make arguments against it.

Within the astika ("orthodox") schools of Hindu philosophy, the Samkhya and the early Mimamsa school did not accept a creator-deity in their respective systems.

The principal text of the Samkhya school, the Samkhya Karika, was written by Ishvara Krishna in the fourth century CE, by which time it was already a dominant Hindu school. The origins of the school are much older and are lost in legend. The school was both dualistic and atheistic. They believed in a dual existence of Prakriti ("nature") and Purusha ("consciousness") and had no place for an Ishvara ("God") in its system, arguing that the existence of Ishvara cannot be proved and hence cannot be admitted to exist. The school dominated Hindu philosophy in its day, but declined after the tenth century, although commentaries were still being written as late as the sixteenth century.

The foundational text for the Mimamsa school is the Purva Mimamsa Sutras of Jaimini (c. third to first century BCE). The school reached its height c. 700 CE, and for some time in the Early Middle Ages exerted near-dominant influence on learned Hindu thought. The Mimamsa school saw their primary enquiry was into the nature of dharma based on close interpretation of the Vedas. Its core tenets were ritualism (orthopraxy), antiasceticism and antimysticism. The early Mimamsakas believed in an adrishta ("unseen") that is the result of performing karmas ("works") and saw no need for an Ishvara ("God") in their system. Mimamsa persists in some subschools of Hinduism today.

Cārvāka The thoroughly materialistic and antireligious philosophical Cārvāka (also known as Lokayata) school that originated in India with the Bārhaspatya-sūtras (final centuries BCE) is probably the most explicitly atheist school of philosophy in the region, if not the world. These ancient schools of generic skepticism had started to develop far earlier than the Mauryan period. Already in the sixth century BCE Ajita Kesakambalin was quoted in Pali scriptures by the Buddhists with whom he was debating, teaching that "with the break-up of the body, the wise and the foolish alike are annihilated, destroyed. They do not exist after death."

Cārvākan philosophy is now known principally from its Astika and Buddhist opponents. The proper aim of a Cārvākan, according to these sources, was to live a prosperous, happy, productive life in this world. In the book More Studies on the Cārvāka/Lokāyata (Cambridge Scholars Publishing, 2020) Ramkrishna Bhattacharya argues that there have been many varieties of materialist thought in India; and that there is no foundation to the accusations of hedonism nor to the claim that these schools reject inference (anumāna) per se as a way of knowledge (pramāṇas).

The Tattvopaplavasimha of Jayarashi Bhatta (c. 8th century) is sometimes cited as a surviving Carvaka text, as Ethan Mills does in Three Pillars of Skepticism in Classical India: Nagarjuna, Jayarasi, and Sri Harsa (2018). It has been claimed that the school died out sometime around the fifteenth century.

In the oldest of the Upanishads, in chapter 2 of the Brhadāranyaka (ca. 700 BCE), the leading theorist Yājnavalkya states in a passage often referred to by the irreligious: "so I say, after death there is no awareness." In the main work by the "father of linguistics", Panini (ca. 4th c. BCE), the main (Kasika) commentary on his affix regarding nastika explains: "an atheist" is one "whose belief is that there is no Hereafter" (4.4.60). Cārvāka arguments are also present in the oldest Sanskrit epic, Ramayana (early parts from 3rd c. BCE), in which the hero Rama is lectured by the sage Javali – who states that the worship of gods is "laid down in the Shastras by clever people, just to rule over other people and make them submissive and disposed to charity."

The Veda philosopher Adi Shankara (ca 790–820), who consolidated the non-dualist Advaita Vedanta tradition, spends several pages trying to refute the non-religious schools, as he argues against "Unlearned people, and the Lokayatikas (…)"

According to the historian Dag Herbjørnsrud, the atheist Carvaka schools were present at the court of the Muslim-born Mughal ruler, Akbar (1542–1605), an inquiring skeptic who believed in "the pursuit of reason" over "reliance on tradition". When he invited philosophers and representatives of the different religions to his new "House of Worship" (Ibadat Khana) in Fatehpur Sikri, Carvakas were present as well. According to the chronicler Abul Fazl (1551–1602), those discussing religious and existential matters at Akbar's court included the atheists:

Herbjørnsrud argues that the Carvaka schools never disappeared in India, and that the atheist traditions of India influenced Europe from the late 16th century: "The Europeans were surprised by the openness and rational doubts of Akbar and the Indians. In Pierre De Jarric's Histoire (1610), based on the Jesuit reports, the Mughal emperor is actually compared to an atheist himself: “Thus we see in this Prince the common fault of the atheist, who refuses to make reason subservient to faith (…)”

Hannah Chapelle Wojciehowski concludes as follows concerning the Jesuit descriptions in her paper “East-West Swerves: Cārvāka Materialism and Akbar's Religious Debates at Fatehpur Sikri” (2015):

The Jesuit Roberto De Nobili wrote in 1613 that the “Logaidas” (Lokayatas) "hold the view that the elements themselves are god". Some decades later, Heinrich Roth, who studied Sanskrit in Agra ca. 1654–60, translated the Vedantasara by the influential Vedantic commentator Sadananda (14th), a text that depicts four different schools of the Carvaka philosophies. Wojciehowski notes: "Rather than proclaiming a Cārvāka renaissance in Akbar's court, it would be safer to suggest that the ancient school of materialism never really went away."

Buddhism