And the fourth line of evidence is
the very low probability of surviving crucifixion. As noted earlier, crucifixion and the torture that many times preceded it was a very brutal process. In fact, only one account exists in antiquity of a person surviving crucifixion. Josephus reported seeing three of his friends crucified. He quickly pleaded with his friend the Roman commander Titus, who ordered that all three be removed immediately and provided the best medical care Rome had to offer. In spite of these actions, two of the three still died. Thus, even if Jesus had been removed from his cross prematurely and medically assisted, his chances of survival were quite bleak. In addition, no evidence exists that Jesus was removed while alive or that he was provided any medical care whatsoever, much less Rome’s best.
Licona summarizes the views of historians with quotes from across the ideological spectrum:
Given the strong evidence for Jesus’ crucifixion, without good evidence to the contrary the historian must conclude that the process killed him. This is the conclusion shared by virtually all scholars who have studied the subject. John McIntyre comments, ‘Even those scholars and critics who have been moved to depart from almost everything else within the historical content of Christ’s presence on earth have found it impossible to think away the factuality of the death of Christ.’ McIntyre is quite correct. Atheist Gerd Ludemann writes, ‘Jesus’ death as a consequence of crucifixion is indisputable.’ Crossan, who denies the authenticity of a large majority of the sayings and deeds attributed to Jesus in the canonical Gospels, comments that there is not the ‘slightest doubt about the fact of Jesus’ crucifixion under Pontius Pilate’ and, ‘That he was crucified is as sure as anything historical can ever be.’ For the Jewish scholar Geza Vermes, ‘The passion of Jesus is part of history.’ The rather skeptical scholar Paula Fredriksen writes, ‘The single most solid fact about Jesus’ life is his death: he was executed by the Roman prefect Pilate, on or around Passover, in the manner Rome reserved particularly for political insurrectionists, namely, crucifixion.’
Licona wraps up his analysis:
In summary, the historical evidence is very strong that Jesus died by crucifixion. The event is multiply attested by a number of ancient sources, some of which are non-Christian and thus not biased toward a Christian interpretation of events. They appear in multiple literary forms, being found in annals, historiography, biography, letters, and tradition in the form of creeds, oral formulas, and hymns. Some of the reports are very early and can reasonably be traced to the Jerusalem apostles. The Passion Narratives appear credible, since they fulfill the criterion of embarrassment and contain numerous plausible details. Finally, the probability of surviving crucifixion was very low.