My point is subtle. We definitely know when the ancient Egyptian civilisation existed, and that has been definitely dated by many coherent methods: carbon dating of artefacts at other sites, historical record, and archeological layers. The issue (which I am perfectly aware merely articulating makes me sound like a kook, but hear me out and know beforehand that I am very skeptical about the likelihood of what I am stating might actually be true) is that we have not got definitive links between the pyramids and the Ancient Egyptian civilisation as we construe it. In most ancient Egyptian texts the pyramids are referred to as being already ancient but claimed to be of their own origin, but in other civilisations (e.g., the ancient Chinese and their claim of the “Yellow Emperor” et al) we have found that civilisations’ own accounts about their origins and claims to being the artificers of grand monuments is not always reliable. What if the pyramids actually predated the ancient Egyptians by millennia, and the ancient Egyptians merely arose later around them, in the same area, and claimed them as their own? There is much pseudoscience in this regard, but certain highly controversial geological observations about the weathering of the Sphinx in particular are particularly telling (in my opinion): it would seem that the prevailing opinion of geologists is that the weathering exhibited on the body of the Sphinx is the product of tens of millennia of water erosion, which is at odds with archeologists’ prevailing opinion is that the erosion “must be” the result of mere millennia of sand erosion, because “we already know” that the Sphinx was built “by the Ancient Egyptians, mere thousands of years before C.E.”. The reasoning is inherently circular, and enrages me. I would very much like to have original artefacts demonstrably linked with the epoch of construction from inside the Pyramids definitely carbon-dated so that this circularity can be once and for all escaped-from. In the end, I fully expect that such independent verification would lead to confirmation that the Pyramids and the Sphinx do indeed date from the early period of the Old Kingdom... but proof would be delightful, and besides, we do other kinds of science (such as running the LHC) in hopes of seeing disagreement with prevailing theories... wouldn't it be amazingly exciting if it turned out that this were not the case? No extraterrestrials... just much deeper human history than we have hitherto fathomed.