Celsus was a Neo-Platonist that lived in the time of the late second century. He wrote a book against Christianity called The True Word. Celsus’s work is only known through the Christian apologist Origen’s writings. Origen of Alexandria was a Christian theologian who cites much of Celsus’s work in his book Against Celsus. Porphyry was a philosopher born in the Roman near East and who wrote in the second half of the third century after the persecutions of Decian and Valerian. His book, Against the Christians, was responded to by various Christian apologists such as Eusibius, Methodius, Jerome and Augustine.

Celsus’s first criticism is to do with God’s descent amongst men. For Celsus, this is an impossibility because God, even by Christian belief, is immutable, unchanging and pure. For God to undergo such a transformation, he would have to go from a pure to a blemished state, from good to bad and Celsus states that this is wrong. Celsus asserts that if God wished to bring about the moral reformation of men he did not need to come down onto the earth because he is omnipotent. In other words God could have used his divine power to enact such a reformation. Cesus also questioned why God only decided to make this action in the generation of Jesus , stating that such an act shows that the Christian idea of God is arbitrary and capricious, which makes Christians a group of impious babblers.

Celsus’s second major criticism of Christianity was the belief in the resurrection of Jesus. As far as Celsus is concerned this is contrary to nature as it reverses the natural process of disintegration and disrupts the order if the world. He questions why God would wish to do such a thing because if God is reason, he obviously is not going to do anything contrary to reason. Therefore, if the Christian believes in a God who does things contrary to reason, they are worshipping a God that is unfit for devotion.

The third major criticism of Christianity for Celsus is the worship of Jesus as God. For Celsus, Jesus was not worthy of being venerated as divine as he was just a low-grade magician not a great hero such as Heracles or Orpheas. The practice of magic was a criminal offence in the Roman Empire and Celsus contends that the miracles of Jesus were simply magic tricks. The Gospels presented Jesus as a wonder worker and Celsus sees the prayers that the Christian’s used as incantations or spells. Celsus contends that by Jesus being conferred the status of God by the Christians that they were making him a rival to the one true God. In Celsus’s view, Jesus’s mortality must make him inferior to God and he asserts that the monotheism of Christians is undone by the adoration of him. As far as Celsus was concerned, Jesus was a lesser deity and excessive adoration robbed the one high God of his proper due.

Porphyry’s first point was that the Book of Daniel had been used by Christians to verify their belief that Jesus was the prophesied Messiah. Porphyry thought that the Old Testament Book of Daniel was a Maccabean pseudograph that had been written contemporarily in the time of Antioch in the second century BC as encouragement for Jewish resistance. The Christian use of the book as a prophecy of Christ’s birth and the destruction of Temple was invalid as far as Porphyry was concerned. He was able to do this through a detailed analysis of the Book of Daniel.

Porphyry’s second point against Christians was their account of the New Testament. He claimed that the disciples based their writings on hearsay because only Matthew and John were eyewitnesses whereas Luke and Mark based their writings on the testimony of the former. Porphyry’s main criticism is that the disciples made Jesus out to be more than he was actually, such things as Jesus being the Son of God, and that he was able to express the word of God through he and God were one was a suspension of belief .

Porphyry also brought to attention the inconsistencies in the writings, behaviour and character of the apostles. One of the main inconsistencies he points to is the conflict between Peter and Paul over circumcision. Porphyry thought that this made the apostles, upon whom the Christians based their belief, unreliable. He points to examples of where there was strife and division in the church from the beginning.

Porphyry’s final and main argument against the Christians was the teaching by the disciples of the worship of Jesus. Porphyry thinks that they are mistaken and that Jesus taught the worship of the one God whereas the disciples turned this into the worship of Jesus. Porphyry thought that the disciples advocated apostacy from their true religion, that of Judaism and questioned why they did not follow the teachings of Moses, or practice the religion inaugurated by Jesus.

The Christian apologist Origen answered these Celsus’s claims by attacking him for being extremely relativistic. Rather than appealing to a specific doctrine that others should follow, for Origen Celsus only appeals to traditon; that things should be done because they were done in the past, that people should obey laws because established social conventions ought to be maintained. Augustine, who wrote a criticism of Porphyry’s work called him the most learned of all, as Porphyry knew the Christian writings as well as any Christian teacher did. However, Augustine states that although the critics of Christianity believe that Jesus should be worshipped as a wise man, he cannot understand why they do not accept that he should be worshipped as God. Augustine states that even Porphyry had to admit from his own consultation with the oracles that Jesus should be praised. Other Christian apologists say they at a loss to understand why such pagans are hostile to the Christians when they both believe in the one true God.

Celsus’s three most important criticisms of Christianity were to do with the Christian beliefs that God came to live amongst men, the belief on the resurrection of Jesus and the worship of Jesus as God. Porphyry’s rested on four core points being the Christian belief in the prophecies of Daniel, the exaggerated fabrication of the life of Jesus, the inconsistencies in Christian writings and the apostacism of Christianity from its foundation belief of Judaism. The Christians apologists responded with incredulity as to why these philosophers were so dependent upon reason and tradition in their arguments against Christianity.