I have been an atheist for a long time, but was raised in a Jewish family and I generally find myself more attracted to Jewish philosophy than to that of other major religions. The one argument that I have often heard brought up for God's existence is based on the Jewish claim of a mass revelation at Sinai. The argument goes that a hoax on such a massive scale would be impossible to pull off; either people would question the lack of eyewitnesses if it was supposed to be a recent event, or people would question why such an extraordinary story was never passed down before if it is claimed to be something that happened in the distant past. Furthermore, if such a massive hoax was somehow pulled off, some other religion would be sure to copy it, especially since it would provide the most solid possible foundation for their beliefs.
There are examples of claims in other religions that have some similarities, but nothing that really seems quite equivalent. How do historians who do not hold the Bible as truth respond to this argument?
I don't work on Biblical history, but I do work on the development of myth. For a long time, historians thought that oral cultures had better memories than we do now with our text-based culture, but that kind of thinking has shifted (as the result of real study and observation of oral cultures). We now know that information basically has maybe only a generation or two of accuracy. Stories get inflated over time, gaps in understanding get filled in with magic and miracles and while the ancients might have had a more skeptical view of events in their own lifetime, when passing on the stories of their parents and grandparents, events were embellished.
Basically there is something like 500 years between the revelation on Mount Sinai and the writing it down, if you think that's a solid basis for historical credibility then you have to lend that same credence to the trials of Hercules and the Odyssey with it's witches and sea goddesses.