In order to understand Jesus, a lot of historical background knowledge is required in order to know what’s expected or normal for the time. Any theory about who Jesus was must account for all the background information.
Terms like messiah, crucifixion, and resurrection were used very broadly in antiquity. Modern definitions are more specific, but we mustn’t mistake our definitions for theirs. Also note that ancients believed air extended all the way to the moon with ether beyond that.
Carrier presents 48 elements in this chapter and the next which must be accounted for whether you believe Jesus existed or not. Some of these elements agree with mainstream biblical scholarship, some are only supported by a few scholars. As I’m just giving a summary, I won’t list the extensive scholarly references that Carrier gives in support of each element.
Element 1: Christianity arose in Syria-Palestine in the early first century.
Element 2: Judaism was incredibly diverse at the time with at least ten competing sects.
Element 3: Jews expected a messiah, but there was much diversity concerning what they expected the messiah to do (e.g., defeat demons vs. defeat the Romans).
Element 4: There were many messiahs at the time. For support of this element, see Book of the Parables of Enoch (written before 70 CE), the Dead Sea Scrolls, and Philo’s book On Rewards and Punishments. The Gospels also mention people expecting Elijah or John the Baptist to rise from the dead. Josephus mentions several. Acts mentions Simon Magus. Whether these messiahs were real or fictional, many Jews believed they were real.
Element 5: Jews expected one of their messiahs to be killed, thus signaling that the end is near. According to the Talmud, the suffering servant of Isaiah 53 is a messiah who dies. There is also a Christ son of Joseph who is pierced to death and rises again. The Talmud dates to the fourth through sixth century, but contains ideas that go back earlier than that. See also Daniel, The Wisdom of Solomon, and the Melchizedek Scroll from the Dead Sea Scrolls.
Element 6: There are logical connections between this messiah and a figure named Jesus Rising (Zechariah 3 and 6). This probably refers to Jesus ben Jehozadak, the first high priest of the second temple whose name literally means Jesus son of Jehovah the Righteous (i.e., Jesus son of God).
Element 7: By some calculations, Daniel predicted the messiah would come in the early first century, even 30 AD. Early Christians considered Daniel to be scripture. This belief may have been a cause of the Jewish War per Josephus and other historians.
Element 8: Jews (including the sect that would become Christianity) searched the scriptures for hidden messages about the messiah.
Element 9: In the early first century, Jews considered other texts to be authoritative in addition to the current Old Testament. Apocryphal and now lost texts were also used. They also used variants of Old Testament texts such as the Septuagint.
Element 10: The death of Jesus was considered an atonement sacrifice by the earliest Christians. Paul’s letters indicate an early high Christology (emphasizes Christ’s divinity rather than his humanity). The earliest Christians believed the end of the world was imminent and only later came to believe in a metaphorical end of the world. Jesus was believed to be a preexisting being, but not identical to god.
Element 11: The earliest known form of Christianity was a Judeo-Hellenistic mystery religion. In other words, it taught eternal salvation for the individual, procured by initiation rituals, involving induction into a set of mysteries. Paul’s epistles are filled with the language of mystery religions. These involved a savior figure who was a son or daughter of god who suffered and gained salvation for members. All these cults involved an initiation ritual symbolically reenacting what the god went through and a ritual meal consisting of wine, bread, or fish. Many involved baptism before Christianity did and tended towards syncretism, monotheism, individualism, and egalitarianism. They were immensely popular centuries before Christianity. Members used fictive kin language like brother, sister, father, and mother.
Element 12: Christians believed they became brothers of the Lord through baptism.
Element 13: Christianity had secret doctrines and different ranks of membership with more advanced members learning more secrets (milk before meat) like other mystery cults.
Element 14: Mystery cults, including Christianity, spoke of their secrets as myths and allegory in public. Some early Christians like Paul believed the Old Testament was allegorical and contained hidden messages, and also wrote allegorically themselves. Just like many pagans read Homer allegorically and Jews like Philo read their scripture allegorically. Christians like Origen and Eusebius insisted the Gospels were meant to be allegorical.
Element 15: Early Christian leaders and members regularly hallucinated, believed their dreams were revelations, practiced glossolalia, etc. Hallucinations can be triggered by ingesting substances, sleep deprivation, fasting, or trance-like states induced by chanting, singing, praying, dancing, etc. Schizotypal people (people who are prone to hallucinations but not in a disabling way like schizophrenics) were revered in the ancient world by religious sects. Hallucinations are referred to as revelations throughout scripture.
Element 16: Christians believed that facts about Jesus obtained through revelation and scriptures were more reliable than facts obtained through word of mouth. Paul insists this in Galatians 1:11 and other places.
Element 17: The main features of the Gospel story can be found in Jewish scripture, especially Isaiah 52-53, The Wisdom of Solomon, Psalms 22-24, Daniel 9 and 12, and Zechariah 3 and 6.
Element 18: Jesus was believed to have done away with the need for Passover and Yom Kippur (and therefor the need for the Temple) by his death. The Eucharist replaced Passover.
Element 19: Paul was the earliest Christian writer we know of, but he only knew of Jesus through revelation.
Element 20: Paul is the first known Christian to dispense with the requirement for Christians to keep Jewish law, although many Christians continued to require obedience to the Jewish law. If Jesus existed, he would have required Torah observance.
Element 21: There were many rival Christian sects, but only a few survived. The winners decided which texts to preserve, so there’s a lot we don’t know about the first Christians.
Element 22: We have no explicit record of the Christian movement between 64 to 95 AD and the leadership of the Christian movement was decimated at the beginning of that period. Acts ends in 64 AD, but isn’t very credible. 1 Clement is dated to 95 AD, but that date isn’t certain. So there’s a lot we don’t know.