Given the time gap between the events recorded in the gospels and the and the estimated time they were written, the fallibility of human memory, and the potential unreliability of eyewitness testimony, the Gospels are not historically reliable with regard to the resurrection of Jesus. The gospels were written decades after the events they describe. They are reliant on the memory of unknown persons, oral traditions, and possibly other written sources that are no longer available. What's wrong with memory? Human memory is fallible, particularly over long periods of time. It's feasible that the authors unintentionally introduced errors while describing the resurrection event. What's the problem with oral tradition? It was a means of transmitting information in societies that were largely illiterate. Unfortunately, as stories are passed down, the retelling of the story can include slightly different details due to memory distortion and reconstruction, and the differences can become amplified as the story is retold many times. We have watched this happen in a manner of minutes of a story being told. If you've ever heard of the telephone game this is a great example of this phenomenon happening. Perhaps the gospels were based on prior sources. If they are, we know nothing about these prior sources. We also have the problem of eye-witness testimony. We perceive events through the lens of our beliefs and biases. Confirmation bias can cause someone to remember details that they perceive as affirming their beliefs while disregarding information that contradict their beliefs. This can influence how we interpret and make sense of it when we're giving an account of it at a later time. This issue can be further compounded when witnesses to an event discuss what they saw. This can lead to a sense of conformity where people alter their memories of an event to align with what is widely agreed upon. Along with an absence of external corroboration that a resurrection occurred, I find the gospels to be unreliable with regard to the resurrection.