Please consider the following:
The New Testament writers would not have known the concept of resurrection without the body. To be sure, there was the concept of the immaterial soul in Platonic philosophy, but the language of the New Testament is not Platonic in this respect. A superficial reading of the New Testament demonstrates this. The Gospels claim that the tomb was empty, which meant that Jesus' body was not there. Now this claim, in and of itself, does not demonstrate that Jesus rose physically, but it does show that resurrection meant to the Gospel writers and their hearers that something had indeed physically happened to Jesus' body. Years ago, the Jewish scholar, Geza Vermes stated that the evidence of the empty tomb of Jesus was incontrovertible. It is outside of the bounds of historical competence to imagine that the disciples knew Jesus was dead, but somehow started proclaiming his "resurrection" because his life and ministry changed their hearts. The Jewish leadership would have seen such a claim as no serious threat-- Christians running around Jerusalem proclaiming that a still dead Jesus had been spiritually raised within them.
By the way, those who proclaim belief in miracles, including the resurrection of corpses, as somehow out of date, are themselves not espousing new, enlightened ideas in their rejection of such things. Such disbelief has been around for centuries; and their divorce of body from spirit is more primitive and older than the claim of bodily resurrection. In some ways, modernism is not so modern after all. None of this, of course, means that we should take a pre-critical approach to the Gospels. Surely not! What it does mean, on our part is that we must have enough humility to be open to the fact that God may indeed work in ways that we can only describe as "miraculous." It is most strange to affirm that God can create life, but cannot nor will not bring life back from the dead.
Moreover, the Apostle Paul bears witness to the necessity of the bodily resurrection of Jesus, not only in 1 Corinthians, but also as he, prior to his conversion, persecuted the first Christians. Ellis Rivkin, another Jewish scholar, asked many years ago what would have set Paul (Saul) off against those early believers? He concludes that it had to be the claim of a bodily raised Jesus. As a Pharisee, Paul would have believed that only the righteous were raised. The claim of Jesus' resurrection meant, therefore, that this Jesus was indeed God's man and God's favor rested upon him. The implications for Paul (Saul) were clear. Once he became convinced of Jesus' resurrection, he had no option but to accept him as God's Anointed.
If indeed the first Christians had non-corporeal visions of Jesus, they would not have used the language of resurrection. In Jewish literature we read of such visions. The Jews had language to describe such visions; it was not the language of resurrection.
I could go on and on, but just one last point: It somewhat mystifies me that more than few individuals whose theology and ethics are centrally concerned with matters of social justice--caring for the poor in this world, and being good stewards of the environment in this world, et al.-- reject the necessity of a bodily raised Jesus. (I am also somewhat mystified that some of those more evangelical insist on a bodily raised Jesus, but who interpret salvation almost exclusively as individual and other-worldly spiritual, making a bodily raised Jesus functionally irrelevant in this world.) The bodily resurrection of Jesus is God's affirmation that this world matters, that God intends to save this world and so it is critically important to seek justice in this life, to feed the poor in this life, and to care for the God's world in this life. An early christological argument for the full humanity of Jesus was "that which he has not become he has not saved." In like fashion, that which Jesus has not overcome he has not defeated. If Jesus' body remained dead, death is still in control and stalks us with no hope for victory. If Jesus' resurrection is simply a metaphor for his spirit rising to be with God, then salvation is nothing more than pie-in-the-sky in the sweet by-and-by. Such faith becomes other-worldly, divorced from the real problems of human existence that God desires to eliminate. When faith is divorced from history, it is divorced from the reality of this world; and when it is divorced from the reality of this world, all that matters is going to heaven when we die. We do not need to be concerned that the poor are fed; after all they will die soon enough and go to be with God. Those who care so much about justice in this world need to embrace the bodily raised Jesus; it is the most powerful affirmation that the work of God in this world matters.
In conclusion, allow me to quote Tom Wright:
Jesus' resurrection is the beginning of God's new project, not to snatch people away from earth to heaven, but to colonize earth with the life of heaven. That, after all, is what the Lord's Prayer is about.
When Paul wrote his great resurrection chapter, 1 Corinthians 15, he didn't end by saying, "So let's celebrate the great future life that awaits us." He ended by saying, "So get on with your work, because you know that in the Lord it won't go to waste." When the final resurrection occurs, as the centrepiece of God's new creation, we will discover that everything done in the present world in the power of Jesus' own resurrection will be celebrated and included, appropriately transformed.We sing during the Easter season, "You ask me how I know he lives? He lives within my heart." Well, that is nice, but it is not good enough. The Jesus who "lives" within my heart is not sufficient to renew all of creation-- more is necessary.
A reductionist faith that minimizes Jesus' resurrection to metaphors and mythologized language cannot meet the challenges of a world in desperate need of resurrection.
The tomb is empty. He is risen indeed!