Heresies and Heretics

Below is a list of well-known heresies and heretics found within real life religions.

For fictional examples, go to The Heretic.

Christianity
"Incredulity is the neglect of revealed truth or the willful refusal to assent to it. Heresy is the obstinate post-baptismal denial of some truth which must be believed with divine and Catholic faith, or it is likewise an obstinate doubt concerning the same; apostasy is the total repudiation of the Christian faith; schism is the refusal of submission to the Roman Pontiff or of communion with the members of the Church subject to him" (CCC 2089)."
 * The Catechism of the Catholic Church has an official definition of heresy, which it juxtaposes against its definitions of incredulity, schism, and apostasy.


 * You may have noticed something important in that definition -- the heresy is only a heresy when it knowingly and willfully contradicts established Catholic teaching. The Catholic Church has a habit of not granting strict definitions to doctrine until it becomes a major issue, due to issues of opportunity and urgency -- the divinity of Christ, while held and intuited by a large portion of Christians to varying degrees, wasn't formally defined until after Constantine legalized Christianity in the early 4th century, for example.
 * NOTE: Since the following points illustrate the history of the Catholic Church's view of heresies, the point-of-view of the history and reasoning is Catholic. You have been warned.
 * An early, biblical example: "But some men came down from Judea and were teaching the brethren, ‘Unless you are circumcised according to the custom of Moses, you cannot be saved.’" -Acts 15:1
 * This counts as a heresy, in spite of its earliness, since it was previously established God's grace could be applied to all regardless of circumcision. "And the faithful of the circumcision, who came with Peter, were astonished, for that the grace of the Holy Ghost was poured out upon the Gentiles also." -Acts 10:45 (Acts 10 is good for general context). Paul also has to deal with the Circumcisers in his Letters to the Romans and the Galations.
 * Gnostic interpretation of Jesus' teachings were declared heretical (in fact, the very word "heresy" was popularized in the Christian world by Christian theologian Irenaeus and his anti-Gnostic tracts), and Gnosticism in general also counts for:
 * Its antipathy for the material universe, which contradicts God's satisfaction with his work as explicit in the first Creation story of Genesis.
 * Instead of human beings being ontologically good creatures in and of themselves, they are spiritual creatures trapped in material form by the Demiurge.
 * Said antipathy for matter likewise denies the Incarnation, which denies Jesus the status of being both True God and True Man.
 * We earlier mentioned the Demiurge trapping human beings in physical form (possibly with well-meaning but ill-fated help from his "mother", Sophia); the Demiurge is also claimed to be the true nature of the monotheistic deity worshiped by Jews, Christians, and Muslims, who falsely claims lordship over all existence and manipulates humanity into violence and misery for shits and giggles. And food.
 * Sabellianism was a 3rd century heresy that claimed God the Father, God the Son, and God the Holy Spirit were not distinct individuals who shared the same nature, but the same person doing different jobs.
 * A very famous example was given to the world in the teachings of Arius, who effectively used orthodox language to teach that Jesus was not divine, but a creature made by God. When Constantine legalized Christianity, one of the first things done by the leaders of the Church to define and formalize what the belief system of Christianity actually held -- Arius, who famously was supported by many bishops and excommunicated by others, gave an explanation of his beliefs to the Council of Nicaea in 325 and was solemnly condemned ; the Council of Nicaea formally proclaimed the divinity of Jesus Christ. Arianism was also an issue at the First Council of Constantinople in 381, where the divinity of the Holy Spirit was also declared.
 * Pelagianism was a 5th century heresy taught by, well, Pelagius, that declared humans morally neutral at birth, and a human's righteousness or sinfulness was the result of the goodness or badness of the people around them, though goodness was defined as imitating the example of Christ. Pelagius denied the doctrine of Original Sin, which, when coupled with Pelagian teaching that Man could reach God under his own power, denied any functional role to God's grace in human nature outside of making holiness easier.
 * Augustine later refuted Pelagianism, but attempts to reconcile these contradictions led to a belief called "Semi-Pelagianism"... which ultimately landed in the same boat as its predecessor, as it still held God's grace was not necessary for purposes of salvation (not to mention several other tenets), plus, while human effort alone could not merit the gift of God's grace, it could make some small claim on its receipt.
 * Nestorianism, the teachings of Nestorius (there are several of these that share their author's name), and another 5th century issue, to boot, holds that the Virgin Mary was not in fact, the Mother of God, and only bore Christ's human nature in her womb A lot of people quickly recognized that this left two Jesuses running around, one man-of-woman-born and one divine, connected via some sort of loosely-defined union. The Council of Ephesus in 431 declared that it was indeed legitimate to refer to Mary as Theotokos, not because she predated or generated God, but because she bore God incarnate.
 * There is some doubt as to whether or no Nestorius himself actually believed or understood the full ramifications of his statements; the Assyrian Church of the East, historically Nestorian, recently signed a joint document on Christology with the Catholic Church and now rejects Nestorianism.
 * Monophysitism was largely concurrent with Nestorianism, mainly because it was a a powerful reaction to and rejection of it. Horrified by the implications of two Christs running around, the monophysites basically leapfrogged themselves to the other end of the spectrum, claiming Jesus had only one nature, part divine and part human, something akin to a demigod. This was likewise rejected on the grounds that, if Jesus was not fully human, he could not fully participate in and thus represent humanity, and if he was not fully divine, he could not fully participate in and thus represent God; in short, since he was neither truly God or truly Man, he could not join the two, and thus he could not fix the problem of Original Sin (see above), and humanity was still basically screwed.
 * Iconoclasm ("icon smashing") first showed up in the 7th and 8th centuries claiming it was sinful to make pictures or statues of Christ and the saints, despite God commanding the creation of religious statues (Ex. 25:18–20; 1 Chr. 28:18–19), including symbolic representations of Christ (cf. Num. 21:8–9 w/ John 3:14). Showed up briefly in the initial stages of the Protestant Reformation, but largely disappeared over the years.
 * Catharism's vogue occurred in the 11th century; technically a mixture of non-Christian religions reworked with Christian terminology, there were a few joining principles that connected the various sects under the name: very similar to Gnosticism above, the Cathars held a fierce antipathy for the material universe, which they held was created by an evil deity (hence, matter is evil), but there exists a Good Deity who should be worshipped instead.
 * One of the largest Catharist sects was that of the Albigensians, who held the spirit was created by the good God, but imprisoned by the evil one in a physical body. Hence, the bearing of children -- the imprisoning of another human soul in a body -- was one of the greatest possible evils; logically, marriage was forbidden... not so logically, fornication was not. There were plenty of fasts that bordered on willful starvation and lots of severe mortification was practiced; leaders went about in voluntary poverty.
 * Protestantism: You've probably heard something about a Reformation in the 16th century, in which thousands of Christians broke with the Catholic Church. Protestantism is not a specific doctrine or belief-set but rather an umbrella term for thousands of different theological divisions (which can generally be un-splintered into less than two dozen religious "traditions"), that share doctrines of Sola Scriptura (theology should be formed solely by consideration of scripture) and Sola Fide . The great diversity of Protestantism has two primary roots: a general distrust for authority and the "doctrine" of private judgment, the latter of which denies the Church its claim to the infallible right to interpret Scripture, and indeed pits the Church against Scripture.
 * An early force in the Protestant Reformation was Martin Luther, a monk who famously nailed his 95 Theses to the door of the Church for the attention of the Bishop. Unfortunately for historical purposes, this event is sometimes simplified to where Martin Luther is depicted as an ostentatious rebel for doing so; however, it was common practice to do so, as the local church was the one place people were going to go by default, so it served as a proto-bulletin. Martin Luther actually put them there in hopes of discussion and debate, but they were quickly copied and spread, leading to a controversy -- and bloodshed -- he hadn't intended to spread. It would be several years until he officially split off.
 * Jansenism -- 17th century. Jansenius, the bishop of Ypres, France, wrote a paper on Augustine that redefined the doctrine of grace. Among other things, the Jansenists taught the Christ died only for those who would ultimately be saved, and not for all men. This and other errors were condemned in 1653 by Pope Innocent X.
 * "Galileo was famously tried before a court for an issue regarding the veracity of heliocentrism" is about as neutral as the popcultural understanding of the actual sequence of events is likely to get; most people seem to think Galileo was declared a heretic. Let's start with the context:
 * In Galileo's day, heliocentrism was actually gaining considerable consideration when considering the motion of the stars from an earthly perspective. A Catholic monk named Nicolaus Copernicus (for whom is named "The Copernican Revolution") famously brought heliocentrism into vogue. He wrote a long text on the subject, On the Revolution of the Celestial Orbs, but put it into the care of a Protestant friend to be published after his death. (The book, which contains an excellent account of heliocentricity, was dedicated to Pope Paul III). The friend, a Lutheran clergyman named Andreas Osiander, anticipated the massive ramifications this theory had for Protestant scriptural interpretation (Martin Luther seemed to condemn the new theory ) and, the likelihood that it might be condemned; to counter this, Osiander prefaced the book with the claim that the descriptions within were theoretical only, and meant to account for the motion of the planets more simply than geocentric models... something Copernicus never intended.
 * Another proponent of heliocentrism was Johannes Kepler, a Protestant who expounded on Copernicus' work; Kepler, who did not couch his developments, faced opposition from fellow Protestants, but found a welcome reception from a number of Jesuits notable for scientific achievement.
 * It is commonly assumed that Galileo proved heliocentrism -- he didn't. Proponents of heliocentrism were unable to counter the strongest argument against it, which had been proposed by Aristotle himself -- if heliocentrism were true, there should be observable parallax shifts in the position of the stars as the earth moved. Now, there are observable parallax shifts, but the technology to demonstrate that hadn't been developed until after Galileo's death. Until that point, the evidence suggested that the stars' positions were fixed relative to the earth; and thus, only the sun, moon, and other planets were.
 * Galileo's attempts at proof relied on "sensible demonstrations" that he claimed were present in Copernicus' work; they weren't exactly forthcoming. Also, the great distance the Copernican theory required was not accepted by many critics, such as another famous astronomer named Tycho Brahe, who didn't fully adopt Copernicus. However, even so, Galileo could very well have continued to propose heliocentrism as a theory on scientific grounds... which he didn't.
 * Galileo not only refused to present his version of heliocentrism as theory, he insisted on taking his "factual" understanding of the universe onto theological grounds, and began insisting Scripture be reinterpreted to suit the theory he couldn't prove (if you haven't caught on, people are touchy about their religion; Galileo really wasn't helping himself); so a non-theologian was essentially going around telling theologians they must take Scripture in a certain sense. In 1616, he appeared before Pope Paul V; the pope, weary of controversy, turned things over to the Holy Office, which condemned the theory. Later, Galileo made a request of a friend - Cardinal Robert Bellarmine, a Jesuit; he was granted a certificate that allowed him not to hold or defend heliocentrism, but to conjecture it. Later, he met with another pope (and a personal friend), Urban VIII, in 1623; he was granted permission to write on the subject, but was cautioned not to advocate it, instead presenting the arguments for or against it. Not happening. What Galileo actually wrote (in the form of a dialogue) was clearly in favor of heliocentrism, and the arguments against it -- including the one offered by his friend the pope -- were placed in the mouth of the character named "Simplicio" (i.e. "Idiot"), who was a debater of obviously inferior intelligence and status than the one arguing heliocentricism.
 * Having publicly mocked his friend and necessary benefactor, alienating the Jesuits to boot with attacks on one of their astronomers, Galileo's actions resulted in the famous trial. While he eventually recanted his teachings, he was not tortured; he was actually merely placed under house arrest... and given a manservant. Indeed, The Directory For Inquisitors (1595) lays down regulations that prevented torture instruments from being used in the circumstances. Galileo was not explicitly declared a heretic, though he was found to be "vehemently suspect" of it; the testimony from his trial (Galileo was tried before an ordinary tribunal) was brought before a group of ten cardinals. Three of them refused to sign his verdict, but his works were eventually condemned.
 * To keep it short, the Church of Galileo’s day issued a non-infallible disciplinary ruling concerning a scientist who was advocating a new and still-unproved theory and demanding that the Church change its understanding of Scripture to fit his. However, it is perhaps just as well, considering both parties were partly right and partly wrong; accepting Galileo's theories would have the Church declaring the sun was the fixed center of the universe as Galileo had. However, the Catholic Church acknowledges its mistake, and has for some time. In 1741, Pope Benedict XIV granted an imprimatur to the first edition of the complete works of Galileo. In 1757, a new edition of the Index of Forbidden Books allowed works that supported the Copernican theory, as science had reached the point where the theory could be proven. Pope John Paul II famously apologized for the fiasco, but there was a second, less well-publicized apology issues about a century earlier; also, the Church has published two stamps in his honor.
 * Joan of Arc was also examined for any possible heretical beliefs. (She got burned on a technicality, dressing as a man.)
 * Origen, a Christian mystic, was accused of Heresy for believing in Universal Redemption.
 * Which is actually false. He is still regard a church father (though not a saint) in most of mainstream christainity. Universal Redemption was a widely accepted doctrine taught by many saints and church fathers at the time (including his teacher St. Clement of Alexandria). The real reason was that about 2 centuries later some of his ideas (deemed "too platonic" were condemned by the church for various reason, but universal redemption was not one of them.

Islam

 * Islam has very strict definition of what its followers should and shouldn't do, and practices that can't be traced into the Prophet himself are regarded as heretical, such practices are known as bid'ah.
 * Ahmadiyyah. Its followers believe that the aforementioned Ahmad is also a Prophet, which goes against the role of Muhammad as the final prophet bringing final scripture. Numerous conflicts, some of which violent, have happened between Ahmadiyyah and the more mainstream Muslims. It doesn't help that it originated during British Colonial era and the early followers had ties with the Colonial authority -- the present headquarter of Ahmadiyyah is in the UK.
 * Sufism. A rather loose term for sects than puts more emphasis in the spiritual experience and, usually, less strict with religious laws. It might have been influenced by Hindu mysticism, and Sufi imams have considerably greater influence on their followers than the mainstream imams. Reactions from mainstream Muslims varies between "let those eccentrics be" to "those are pseudo-Islam, exterminate them."
 * Sunni and Shi'a Muslims regard each other as heretics. Comparison can be drawn between Catholicism and the Eastern Orthodox Church, who has been in mutual excommunications since, like, forever. Let's leave it at that.
 * And finally, other Abrahamic religions are regarded as heresy in Islam because supposedly, God designates Islam as the only religion in the world, rendering the other Abrahamic religions obsolete with the coming of Qur'an. Let's leave it at that.

Judaism
Section not finished yet.

Other religions

 * Pre-Christian example: the 18th-dynasty pharaoh Akhenaten radically and single-handedly overhauled the Egyptian religion from polytheism into sort of a proto-monotheism. He got away with it at the time because, well, he was the king, but the religion reverted immediately after he died and Akhenaten got the Unperson treatment from his successors.