But Jesus has been dead for 2000 years. How can you verfie that?
You look at the historical data you have, and what you know about the ways people and communities operate.
There are some other references to Jesus elsewhere - and all serious historians agree he was a real person who was really crucified so we need only look at the historicity of the Resurrection. Most historians are also agreed that the tomb was empty on easter morning.
So you need to look closely at what the New Testament authors said the resurrection was and what the did about it, and then decide in what possible ways that data could have arrisen.
The resurrection is the central idea that the early christian communities built everything else on, and there is nothing like it in the surrounding paganism that held firmly to the idea that dead people stay dead. The Jewish communities had an idea of resurrection of the dead at the end of the age, but that was firmly something that could and would only happen at the end of the age to all God's people, not on one sunday morning to one person.
What should have happened when Jesus was crucified is that his followers gave up on him. Crucifixion is the ultimate proof that one is not the messiah - that's the whole point of crucifying people. His disciples would be left with two options, give up and go home quietly or transfer their understanding of who the messiah was to his brother James. Those are the two options that are played out in every other would be messiah when they are killed. And yet that's not what happened here.
Instead his early followers claimed that something they knew to be as impossible as you and I know it to be - happened, and they rebuilt their entire lives and philosophy from the ground up on the reality of that event. People don't do that in the space of 20 years unless (a) there is somewhere for those ideas to have come from (which there is not) or (b) they really did believe that they had seen his tomb empty and seen and touched his risen person and talked with him.
There are several other indicators that make no sense if they are making it up, eg:
- the prominent role of the women as first witnesses in a world where women are not valid witnesses
- the description of the risen Jesus - the only Old Testament text that says what people will look like when they are resurrected is in Daniel 12, when it says that they will shine like stars - if they were making it up they would surely include that description.
On the other hand, if you can find evidence that there was a body, or that they got their ideas from somewhere else, that would count against a resurrection. You cannot prove the Resurrection, but it is investigatable by the tools of history, in a way that the central claims of other faiths are not.
