Endo comes down on the side of the resurrection being real.
But he also records the idea of some people at the time that the "resurrection" was merely that John the Baptist had been reborn in Jesus. He also notes that the disciples themselves didn't think of a Messiah in terms of a resurrection. They thought of him as a leader who would reclaim Israel, restoring it to its former independence and glory. Jesus was a "glorious person," the one who was to "liberate the territory of Israel." (172) Then, when he died, the disciples remembered him most vividly as a "companion" and he became still so real to them that he remained "very close to them." This was "no act of abstract meditation; it was a non-metaphoric, tangible realization," Endo writes (174). This could be what was meant by resurrection.
On the other hand, Endo asks how this religious sect could have lasted without the reality of the resurrection. It had to have grown large from more than a desire for companionship. To Endo, the disciples were cowards who had betrayed Jesus. He believed they would not have been strong enough to continue to do anything more than admire Jesus as a great moral teacher if something supernatural hadn't occurred. They would not have grown into people who were unafraid of physical terror. What caused them to change was a transformative event of "electrifying intensity:" (177) the physical resurrection.