How would the scientists know? Uh, because they tested the documented technologies of the time. Or was that a trick question?

You should look again. Building is based on physics (i.e. science). What loads will a particular material withstand? For example, concrete is VERY high in compressional strength, but comparitively weak in tensional/torsional strength. Scientists measured this. So rebar (steel rods/grids) were added to concrete slabs to add tensional strength.

Melting and flashpoints of materials are tested by scientists, and these results are used (for example) to decide on buidling codes. Skyscrapers must be built to withstand X degrees of heat for Y minutes, and/or have extra heat protection.

The people who sign off on the plans for buildings are civil engineers. The lowest degree is a Bachelor of Science. Then Master of Science, then Doctor of Science. So the folks riveting the beams may or may not be scientists, but the designers are.

Back to the pyramids. There is plenty of documentation that Egyptians used copper saws. Copper saws will not cut granite. They don't even do that well on limestone (the outside blocks). Although theoretically possible, it is highly unlikely that the Egyptians would leave a shitton of documentation and artifacts that they had copper saws, but nothing indicating they had higher technology.

There is also a time factor, i.e. how long to quarry, mine, cut, finish, move, and place. 2,300,000 million limestone blocks each weighing 2,5 metric tons. And that is just the outside. The inside is far more complex, both from materials and geometry (i.e. also science).

Oh, and the leveling accuracy for the pyramids is at a late 20th century level (pun intended).

There is a relatively new theory that maybe the outside blocks were poured, but I haven't had time to do more than cursory research.

I'm not so egotistical that my opinion is based solely on my personal imagination and experience. I was listing what is documented and researched.

Just as I'll take the time to look up the PBS proof video you mentioned, I'll leave you look up the information I've commented about.

Addressing your very first point, Keith could have gone into great detail not only about the pyramids themselves, but what he alluded to in his first paragraph, that there are great similarities between sites around the world, at a time when intercontinental travel and communication would take months in one direction.

Keith was being kind that we (modern man) think we know all the details of human history. There are dozens of carbon dated artifacts that bely the chononlogy in our history books.