Eschatology (from the Greek ἔσχατος, Eschatos meaning "last" + -logy) is a part of theology and philosophy concerned with the final events in the history of the world, or the ultimate destiny of humanity, commonly referred to as the end of the world. While in mysticism the phrase metaphorically refers to the end of ordinary reality and reunion with the Divine, in many traditional religions it is taught as an actual future event prophesied in sacred texts or folklore. More broadly, eschatology may encompass related concepts such as the Messiah or Messianic Age, the end time, and the end of days.
The Greek word αἰών (aeon), meaning "age", may be translated as "end of the age (or historical period)" instead of "end of the world". The time distinction also has theological significance; while the end of time in mystical traditions relates to escaping confinement in the "given" reality, some religions believe and fear it to be the literal destruction of the planet (or of all living things) - with the human race surviving in some new form, ending the current "age" of existence.
Most Western monotheistic religions have doctrines claiming that "chosen" or "worthy" members of the one true religion will be "spared" or "delivered" from the coming judgment and wrath of God. For Judaism, see Isaiah. For Christianity, see the Book of Revelation. They will be ushered into paradise either before, during, or afterwards depending upon the end-time scenario to which they hold.
Eschatology has also been a belief shared, sometimes theorized, by philosophers. Saint Augustine has been one of the most famous eschatological thinkers, followed by Hegel's philosophy of history, and, some have argued Marxists – as a secular religion. Theodicy has gathered together most Enlightenment thinkers, among whom are Kant and Rousseau.
More recently, many involved in futures studies and transhumanism note the accelerating rate of scientific progress and anticipate a technological singularity in the 21st century that would profoundly and unpredictably change the course of human history. Artist/futurist Michael E. Arth, for example, speculates about the emergence of a hive-like distributed being that would be self-conscious, integrated into a future version of the Internet, and also able to exhibit any individualized form, or speak any language. This collective intelligence, UNICE: Universal Network of Intelligent Conscious Entities, would connect everyone on the planet before it spreads outward into space.
For the eschatological beliefs of various religions, see: End Times.
Christian eschatology relies on the book of Revelation for its main source, though other parts of the Bible, such as the Olivet discourse in Matthew are also relevant, as well as the writings in the book of the prophet Daniel. Christians believe that Jesus will return to Earth at the end of the world to defeat Satan and establish his rule for all eternity.
There are however many different views regarding the exact order of the events. Much of the dispute concerns the interpretation of a passage in Revelation concerning the thousand-year (or millennial) rule of Christ on Earth. Some, called premillennials hold that Christ will return prior to the millennium to defeat Satan, and then establish a thousand-year rule on Earth whilst Satan is imprisoned. At the end of the thousand years, Satan will be released for a final battle, where he will once again be defeated, and this time condemned to hell for all eternity. After this the Final Judgment will occur, where each person will be consigned to either hell or heaven.
Premillennialism is the most literal interpretation of the passage concerned, but many prefer less literal interpretations, considering the primillennial interpretation unparsimonious. Postmillennials hold that the thousand-year rule will be a period in which Christianity comes to dominate the planet; only once the vast majority of the planet has been converted will Christ return, to defeat Satan and condemn him to hell. Postmillennials believe that the world will get progressively better (from a Christian perspective) prior to Christ's return, while premillennials envisage it falling into depravity. Postmillennialism was very common in the late 1800s and early 1900s, prior to World War I. As a movement it was related to the political justification for the existence of the Holy Roman Empire.
Amillennials hold that the millennium represents the period between Christ's death and resurection, and his Second Coming: that is, the age of the Church. This view is related to the understanding of a millennium as a short time period to God, with an inexact extent. (The word millennium is Latin, not Greek.)
Preterists believe that the passages in the Bible which are normally taken to refer to the end of the world, in fact refer to events in the first century A.D., such as the persecution of Christians by the Roman Emperor Nero.
Premillennials are also divided on the issue of the so-called rapture. Pretribulationists believe that Christ will return twice. At the beginning he will return to rescue those who are Christians at the time, and then disappear again. This will be followed by a seven-year period of suffering, in which the Antichrist will conquer the world and kill those who refuse to worship him. At the end of the seven years, Christ will return a second time to defeat the Antichrist, and rescue the Jews and those who have converted to Christianity during the tribulation. Posttribulationists hold that Christ will not return until the end of the tribulation, which Christians will suffer through along with everyone else.
The belief in a rapture implied by pretribulationism is often criticized, on the grounds that it results in Christ returning twice. Pretribulationists defend it on the basis of a passage in 2 Thessalonians.
Amillennialism is the belief of the Catholic church, and also of many Protestants. Premillennialism is popular among many conservative Protestants, such as Hal Lindsey. It has been popularised recently by the Left Behind series of novels and films. Postmillennialism is favoured by among Christian Reconstructionists such as Gary North and Gary Bauer.