"According to Joseph Campbell, there is not one scrap of evidence, outside of the Bible, to prove that the Jews were ever slaves in Egypt. Any thoughts here?"

Interesting, Kendall. It was on TV I admit, but I've seen Hebrew graffiti carved by slaves who were forced to work in opal mines by Eygptians. The city of Ramses they were supposed to have built in captivity has been found, made of mud brick as described. Slaves wearing what look like Hebrew garment have been found drawn on tomb walls. There's even some evidence for Joesph. How much to expect to be found about slaves 3,500 years after the fact?

GUEST, Joesphus's reference to Jesus is found in the earliest texts. It is clear that it was elaborated by a scribe in later years, but it was there. Joesphus even mentions John the Baptist and cites his treatment as the reason Herod came to a bad end. Here's the version with the additions in ALL CAPS. What you see between them is hardly that unsual for a devote Jew to have written, nor does the the amount of text seem unreasonable for what must have seemed like one more failed Messiah to Joesphus. On the other hand, if Christians had added the whole thing, it would have a completely different tone and, I assure you, have been much, much longer. Read St. Augustine's work. It's interminable.

"Now there was about this time Jesus, a wise man IF IT BE LAWFUL TO CALL HIM A MAN, for he was a doer of wonders, A TEACHER OF SUCH MEN AS RECEIVE THE TRUTH WITH PLEASURE. He drew many after him BOTH OF THE JEWS AND THE GENTILES. HE WAS THE CHRIST. When Pilate, at the suggestion of the principal men among us, had condemned him to the cross, those that loved him at the first did not forsake him, FOR HE APPEARED TO THEM ALIVE AGAIN THE THIRD DAY, AS THE DIVINE PROPHETS HAD FORETOLD THESE AND THEN THOUSAND OTHER WONDERFUL THINGS ABOUT HIM, and the tribe of Christians, so named from him, are not extinct at this day."
(Antiquities 18:63-64)