The view that Jesus was a divine being who only appeared to be human, explicitly branded as a heresy by Ignatius (d. 107 CE), though it may have existed earlier. It derives from Hellenistic dualism: the idea that what is created is tainted, ‘fleshly’, and mortal, whereas the divine realm is good, spiritual, and immortal. So, the docetist argument ran, because Jesus the Saviour belongs to the divine realm, he cannot have been truly human.
Some scholars believe that there are indications of docetic thought within the gospel of John, especially in ch. 17. It is claimed that in the fourth gospel Jesus lacks the human characteristics of compassion and mercy; that he is never properly exposed to the sickness and sufferings of our world; and that he is so manifestly ‘always on the side of God’ that he has no solidarity with humanity.
Against this it is urged that the hallmark of Johannine Christology is John 1: 14, ‘the Word was made flesh’, and that the authenticity of Jesus' humanity is demonstrated in John's gospel by the references to Jesus' mother (2: 1–11) and brothers (7: 3–10); his weariness at the well in Samaria (4: 6); his thirst (4: 7); his grief (John 11: 33); his death. On this evidence it is held that the Christology of John is not docetic: Jesus shares his humanity with all other human persons.