Jesus' resurrection and history

Last week I took part in a debate hosted by the Atheist, Agnostic and Student Society at Murdoch University. I argued that God exists and gave historical evidence for Jesus' resurrection as my first reason for this belief. I explained that what historians look for in assessing historical claims is whether we have multiple, contemporary, independent accounts. On these criteria we have better evidence for Jesus' resurrection than we have for Julius Caesar crossing the Rubicon or even for the life of Alexander the Great.

My opponents replied that lots of religions make similar cases for miraculous foundations (and obviously they can't all be right). The 3 examples they gave were Mormonism, Pythagoras and Apollonius of Tyana. They claimed that none of the 12 Mormon witnesses ever reversed their testimony to seeing Joseph Smith's 'Golden Plates' and that both Pythagoras' and Apollonius' contemporaries testified to their miraculous powers.

Having responded that record of Apollonius dates to the 3rd century (nearly 200 years after his life) I decided to take my own advice and look at the evidence for the other 2 claims. I soon discovered that witnesses to Smith's Golden Tablets later said they never saw them, and records of Pythagoras comes from 800 years after his death.

​This isn't the first time I've had this experience. A bit of research has shown other historical claims to the miraculous to be unfounded. Which leaves me asking, 'What grounds do we have to doubt Jesus' resurrection - an event with multiple, independent contemporary witnesses?'