Over all of Egyptian history. The time periods that specifically had slaves I would like to have pointed out, and then contrasted with the time periods that did not.
I would say that ancient Egypt had slaves throughout most of their history, from Pre-Dynastic times all the way up to the Ptolemies. Slavery was fairly endemic in that region at that time. You built up an army, you marched out, you conquered some poor, unsuspecting town, and you brought back slaves. And Egypt had one of the best armies around for quite a long time. So, it would be atypical if Egypt did
not have slaves.
What time periods did Egypt not have slaves? There aren't a lot of records from pre-Narmer days, so Egypt may not have had slaves at that time. The only other period I can think of would be the First Intermediate Period. Little is known about this time as well. But we have some writings from folks like Manetho which point to some fairly radical social upheavals. Plus, very little was accomplished during this time. So, there may have been few, if any, slaves during 1st Intermediate.
What I learned in my Humanities class was that most of those used in the working of the pyramids were in the middle class; skilled labor above slave labor. That Egypt had the highest amount of middle class labor out of all civilizations.
I'd say that's pretty accurate. Egypt did indeed have a huge middle class. The reason for this was bureaucracy. Egypt was nothing if not a highly bureaucratic state. They loved making up rules and recording things. Heck, they loved it so much that they had to have two capitals just to accomodate all the red tape. Memphis was the "state" capital while Thebes the "religious" capital, though the roles did overlap somewhat.
But, to get back on track, this massive bureaucracy had to be staffed. And that's where the middle class came in.
However, as far as I know, the Middle Class was not used to build the Pyramids either. The Pyramids were, I believe, built by skilled stonemasons supplemented by farmers during Inundation.
Slaves most certainly were not used to build the pyramids. There was just no way a Pharaoh would allow a filthy foreigner slave anywhere near his tomb.
Okay, but is there any actual evidence?
Of Egyptian slaves? Yes. That they supplemented the regular work force? Well, yes and no. As I said above, slaves did not work on the pyramids. So, there's no evidence there.
But, slaves did help build some things. Store Cities come to mind. These were cities built along the Mediterranean in the Suez region meant to supply the Egyptian military as they would march out to the Levant to fight whoever was the enemy du jour. Slaves were most definitely used to build these.
Slaves were also used to make bricks. Most ancient Egyptian buildings, including palaces, were made of mud and straw bricks. Needless to say, making bricks was a thankless, grueling task. A perfect activity for a slave. Plus, there was the added symbolism of the captured enemy helping to build the palace of his captor. The Egyptians would have enjoyed that.
A couple of other tasks that come to mind: quarrying granite and sex slaves. So, yes, slaves were around and they were put to good use.
Do most (credible) historians actually agree that it was most likely there were slaves used?
Again, not to build the pyramids, no. No credible Egyptologist believes this. But, I think most agree that slaves did have a role to play in Egyptian infrastructure.
Right, the whole enslaving the Israel people. Seems kinda odd that it would be mentioned if it didn't happen, as much as I criticize the Bible for not being an accurate historical document...
The Israelite issue is a completely different can of worms, which I will try not to get into. However, I will say that I do believe that an ethnic group that would someday become the Israelites did indeed live in Egypt for a time. I do not believe that they numbered in the hundreds of thousands, nor even the tens of thousands. I doubt that there was any sort of dramatic escape from the clutches of the Pharaoh. And I'm not so sure that they were ever slaves. But, I do believe the writer of Genesis did base some of his story on fact. That's the best I can commit to at this point, as I haven't researched the issue thoroughly.
