Celsus (Greek: Κέλσος) was a 2nd century Greek philosopher and opponent of Christianity. He is known to us mainly through the reputation of his literary work, The True Word (Account, Doctrine or Discourse) (Λόγος 'AληΘής), almost entirely reproduced in excerpts by Origen in his counter-polemic Contra Celsum of 248, 70 or 80 years after Celsus wrote.
It is generally supposed that Celsus was a Greek or Roman. His professed acquaintance, however, with the Jewish religion and his knowledge, such as it was, of Egyptian ideas and customs incline some historians to think he belonged to the Eastern portion of the empire. Those who believe him to have been a Roman explain his knowledge of Jewish and Egyptian matters by assuming that he acquired that knowledge either by travelling, or by mingling with the foreign population of Rome.
Celsus wrote his work The True Word as a polemic against the Christians in approximately 178 CE., or generally between 170 and 180 CE. Celsus divided the work into two sections, the one in which objections are put in the mouth of a Jewish interlocutor and the other in which Celsus speaks as the pagan philosopher that he is. Celsus ridiculed Christians for what he perceived to be an advocacy of blind faith instead of reason. About 60 years after it was first published, the book written by Celsus inspired a massive refutation by Origen in Contra Celsum, which is our source of knowledge for Celsus, who was later condemned along with other critics such as Porphyry.
The idea of an incarnation of God is absurd; why should the human race think itself so superior to bees, ants and elephants as to be put in this unique relation to its maker? And why should God choose to come to men as a Jew? The Christian idea of a special providence is nonsense, an insult to the deity. Christians are like a council of frogs in a marsh or a synod of worms on a dunghill, croaking and squeaking, "For our sakes was the world created."
To Celsus, it was much more reasonable to believe that each part of the world has its own special deity; prophets and supernatural messengers had appeared in more places than one. Besides being bad philosophy based on fictitious history, Christianity is not respectable. Celsus does not indeed repeat the Thyestean charges so frequently brought against Christians, but he says the Christian teachers who are mainly weavers and cobblers have no power over men of education. The qualifications for conversion are ignorance and childish timidity.
"Like all quacks they gather a crowd of slaves, children, women and idlers. I speak bitterly about this", says Celsus, "because I feel bitterly. When we are invited to the Mysteries the masters use another tone. They say, Come to us you who are of clean hands and pure speech, you who are unstained by crime, who have a good conscience towards God, who have done justly and lived uprightly. The Christians say, Come to us you who are sinners, you who are fools or children, you who are miserable, and you shall enter into the kingdom of Heaven: the rogue, the thief, the burglar, the poisoner, the despoiler of temples and tombs, these are their proselytes.
"Jesus, they say, was sent to save sinners; was he not sent to help those who have kept themselves free from sin? They pretend that God will save the unjust man if he repents and humbles himself. The just man who has held steady from the cradle in the ways of virtue He will not look upon. He pours scorn upon the exorcists; who were clearly in league with the demons themselves – and upon the excesses of the itinerant and undisciplined prophets who roam through cities and camps and commit to everlasting fire cities and lands and their inhabitants.
"Above all Christians are disloyal, and every church is an illicit collegium, an insinuation deadly at any time, but especially so under Marcus Aurelius. Why cannot Christians attach themselves to the great philosophic and political authorities of the world? A properly understood worship of gods and demons is quite compatible with a purified monotheism, and they might as well give up the mad idea of winning the authorities over to their faith, or of hoping to attain anything like universal agreement on divine things."
An interesting feature of Celsus' writing is that he refers to Jesus' father by name as Panthera. It is taken by Celsus as given that Jesus was the illegitimate son of a roman soldier of this name. There exists the tomb of such a roman soldier who was in the area at this time in Bad Kreuznach in Germany, namely Tiberius Julius Abdes Pantera.
In his antipathy to Christianity, which appears to him barbaric and superstitious, he gives himself up to the scepticism and satire of a man of the world through which he comes in contact with Epicurean tendencies. He quotes approvingly from the Timaeus of Plato: It is a hard thing to find out the Maker and Father of this universe, and after having found him it is impossible to make him known to all. Philosophy can at best impart some notion of God which the soul must itself develop. The Christian on the contrary maintained that God is known to us as far as need be in Christ, and He is accessible to all. Another sharp antithesis was the problem of evil. Celsus saw evil as a constant of the material world. Hence his scorn of the doctrine of the resurrection of the body held then in a very crude form, and his ridicule of any attempt to raise the vulgar masses from their degradation. The real root of the difficulty to Platonist as to Gnostic was his sharp antithesis of form as good and matter as evil.
The date also is clearly defined. Besides the general indication that the Empire was passing through a military crisis, which points to the long struggle waged by Marcus Aurelius against the Marcomanni and other Germanic tribes, there is a reference (Contra Celsum, viii.69) to the rescript of that emperor impressing on governors and magistrates the duty of keeping a strict watch on extravagances in religion. This edict dates from 176‑177, and inaugurated the persecution which lasted from that time till the death of Marcus Aurelius in 180. During these years Commodus was associated in the imperium, and Celsus has a reference to this joint rule (viii.71).
The gnostic sects and their writings were well known to him (viii.15 and vi.25), and so was the work of Marcion. There are indications, too, of an acquaintance with Justin Martyr and the Sibylline literature (vii. 53, cp. v.61). He is perfectly aware of the internal differences among Christians, and he is familiar with the various stages of development in the history of their religion. These are cleverly employed in order to heighten the impression of its instability. He plays off the sects against the Catholic Church, the primitive age against the present, Christ against the apostles, the various revisions of the Bible against the trustworthiness of the text and so forth, though he admits that everything was not really so bad at first as it is at present.
Of more importance than these matters is the light which the book sheds on the strength of the Christian Church about the year 180. It is arguable that Celsus had insufficient apprehension of the spiritual inclinations that Christianity claimed to satisfy, and he underrated the significance of the Church, regarding it simply as one of a number of warring sects (mostly Gnostic), and so seeing only a mark of weakness. Yet there is all through an undercurrent which runs against his surface verdicts, and here and there comes to expression. He admits that Christianity has been stated reasonably; against the moral teaching of Jesus he only brings the charge of plagiarism; and with the Christian assertion that the Logos is the Son of God he completely accords.
Most suggestive, however, is his closing appeal to the Christians: "Come", he says, "don't hold aloof from the common regime. Take your place by the emperor's side. Don't claim for yourselves another empire, or any special position. It is an overture for peace. If all were to follow your example and abstain from politics, the affairs of the world would fall into the hands of wild and lawless barbarians (viii.68)."
Conceding that Christians are not without success in business (infructuosi in negotiis), he wants them to be good citizens, to retain their own belief but conform to the state religion. It is an earnest and striking appeal on behalf of the Empire, which was clearly in great danger, and it shows the terms offered to the Church, as well as the importance of the Church at the time. Numerically, Christians may have formed perhaps a tenth of the population, i.e. in Alexandria there would be 50,000-60,000, but their influence was greater than these numbers suggest.